Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/fork.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
9 | * 'fork.c' contains the help-routines for the 'fork' system call | |
10 | * (see also entry.S and others). | |
11 | * Fork is rather simple, once you get the hang of it, but the memory | |
12 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
13 | */ | |
14 | ||
b3e58382 | 15 | #include <linux/anon_inodes.h> |
1da177e4 | 16 | #include <linux/slab.h> |
4eb5aaa3 | 17 | #include <linux/sched/autogroup.h> |
6e84f315 | 18 | #include <linux/sched/mm.h> |
f7ccbae4 | 19 | #include <linux/sched/coredump.h> |
8703e8a4 | 20 | #include <linux/sched/user.h> |
6a3827d7 | 21 | #include <linux/sched/numa_balancing.h> |
03441a34 | 22 | #include <linux/sched/stat.h> |
29930025 | 23 | #include <linux/sched/task.h> |
68db0cf1 | 24 | #include <linux/sched/task_stack.h> |
32ef5517 | 25 | #include <linux/sched/cputime.h> |
b3e58382 | 26 | #include <linux/seq_file.h> |
037741a6 | 27 | #include <linux/rtmutex.h> |
1da177e4 LT |
28 | #include <linux/init.h> |
29 | #include <linux/unistd.h> | |
1da177e4 LT |
30 | #include <linux/module.h> |
31 | #include <linux/vmalloc.h> | |
32 | #include <linux/completion.h> | |
1da177e4 LT |
33 | #include <linux/personality.h> |
34 | #include <linux/mempolicy.h> | |
35 | #include <linux/sem.h> | |
36 | #include <linux/file.h> | |
9f3acc31 | 37 | #include <linux/fdtable.h> |
da9cbc87 | 38 | #include <linux/iocontext.h> |
1da177e4 | 39 | #include <linux/key.h> |
50b5e49c | 40 | #include <linux/kmsan.h> |
1da177e4 LT |
41 | #include <linux/binfmts.h> |
42 | #include <linux/mman.h> | |
cddb8a5c | 43 | #include <linux/mmu_notifier.h> |
1da177e4 | 44 | #include <linux/fs.h> |
615d6e87 | 45 | #include <linux/mm.h> |
17fca131 | 46 | #include <linux/mm_inline.h> |
ab516013 | 47 | #include <linux/nsproxy.h> |
c59ede7b | 48 | #include <linux/capability.h> |
1da177e4 | 49 | #include <linux/cpu.h> |
b4f48b63 | 50 | #include <linux/cgroup.h> |
1da177e4 | 51 | #include <linux/security.h> |
a1e78772 | 52 | #include <linux/hugetlb.h> |
e2cfabdf | 53 | #include <linux/seccomp.h> |
1da177e4 LT |
54 | #include <linux/swap.h> |
55 | #include <linux/syscalls.h> | |
56 | #include <linux/jiffies.h> | |
57 | #include <linux/futex.h> | |
8141c7f3 | 58 | #include <linux/compat.h> |
207205a2 | 59 | #include <linux/kthread.h> |
7c3ab738 | 60 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 61 | #include <linux/rcupdate.h> |
1da177e4 LT |
62 | #include <linux/ptrace.h> |
63 | #include <linux/mount.h> | |
64 | #include <linux/audit.h> | |
78fb7466 | 65 | #include <linux/memcontrol.h> |
f201ae23 | 66 | #include <linux/ftrace.h> |
5e2bf014 | 67 | #include <linux/proc_fs.h> |
1da177e4 LT |
68 | #include <linux/profile.h> |
69 | #include <linux/rmap.h> | |
f8af4da3 | 70 | #include <linux/ksm.h> |
1da177e4 | 71 | #include <linux/acct.h> |
893e26e6 | 72 | #include <linux/userfaultfd_k.h> |
8f0ab514 | 73 | #include <linux/tsacct_kern.h> |
9f46080c | 74 | #include <linux/cn_proc.h> |
ba96a0c8 | 75 | #include <linux/freezer.h> |
ca74e92b | 76 | #include <linux/delayacct.h> |
ad4ecbcb | 77 | #include <linux/taskstats_kern.h> |
522ed776 | 78 | #include <linux/tty.h> |
5ad4e53b | 79 | #include <linux/fs_struct.h> |
7c9f8861 | 80 | #include <linux/magic.h> |
cdd6c482 | 81 | #include <linux/perf_event.h> |
42c4ab41 | 82 | #include <linux/posix-timers.h> |
8e7cac79 | 83 | #include <linux/user-return-notifier.h> |
3d5992d2 | 84 | #include <linux/oom.h> |
ba76149f | 85 | #include <linux/khugepaged.h> |
d80e731e | 86 | #include <linux/signalfd.h> |
0326f5a9 | 87 | #include <linux/uprobes.h> |
a27bb332 | 88 | #include <linux/aio.h> |
52f5684c | 89 | #include <linux/compiler.h> |
16db3d3f | 90 | #include <linux/sysctl.h> |
5c9a8750 | 91 | #include <linux/kcov.h> |
d83a7cb3 | 92 | #include <linux/livepatch.h> |
48ac3c18 | 93 | #include <linux/thread_info.h> |
afaef01c | 94 | #include <linux/stackleak.h> |
eafb149e | 95 | #include <linux/kasan.h> |
d08b9f0c | 96 | #include <linux/scs.h> |
0f212204 | 97 | #include <linux/io_uring.h> |
a10787e6 | 98 | #include <linux/bpf.h> |
b3883a9a | 99 | #include <linux/stackprotector.h> |
fd593511 | 100 | #include <linux/user_events.h> |
cd389115 | 101 | #include <linux/iommu.h> |
1da177e4 | 102 | |
1da177e4 | 103 | #include <asm/pgalloc.h> |
7c0f6ba6 | 104 | #include <linux/uaccess.h> |
1da177e4 LT |
105 | #include <asm/mmu_context.h> |
106 | #include <asm/cacheflush.h> | |
107 | #include <asm/tlbflush.h> | |
108 | ||
ad8d75ff SR |
109 | #include <trace/events/sched.h> |
110 | ||
43d2b113 KH |
111 | #define CREATE_TRACE_POINTS |
112 | #include <trace/events/task.h> | |
113 | ||
ac1b398d HS |
114 | /* |
115 | * Minimum number of threads to boot the kernel | |
116 | */ | |
117 | #define MIN_THREADS 20 | |
118 | ||
119 | /* | |
120 | * Maximum number of threads | |
121 | */ | |
122 | #define MAX_THREADS FUTEX_TID_MASK | |
123 | ||
1da177e4 LT |
124 | /* |
125 | * Protected counters by write_lock_irq(&tasklist_lock) | |
126 | */ | |
127 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 128 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 | 129 | |
8856ae4d | 130 | static int max_threads; /* tunable limit on nr_threads */ |
1da177e4 | 131 | |
8495f7e6 SPP |
132 | #define NAMED_ARRAY_INDEX(x) [x] = __stringify(x) |
133 | ||
134 | static const char * const resident_page_types[] = { | |
135 | NAMED_ARRAY_INDEX(MM_FILEPAGES), | |
136 | NAMED_ARRAY_INDEX(MM_ANONPAGES), | |
137 | NAMED_ARRAY_INDEX(MM_SWAPENTS), | |
138 | NAMED_ARRAY_INDEX(MM_SHMEMPAGES), | |
139 | }; | |
140 | ||
1da177e4 LT |
141 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; |
142 | ||
c59923a1 | 143 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
144 | |
145 | #ifdef CONFIG_PROVE_RCU | |
146 | int lockdep_tasklist_lock_is_held(void) | |
147 | { | |
148 | return lockdep_is_held(&tasklist_lock); | |
149 | } | |
150 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
151 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
152 | |
153 | int nr_processes(void) | |
154 | { | |
155 | int cpu; | |
156 | int total = 0; | |
157 | ||
1d510750 | 158 | for_each_possible_cpu(cpu) |
1da177e4 LT |
159 | total += per_cpu(process_counts, cpu); |
160 | ||
161 | return total; | |
162 | } | |
163 | ||
f19b9f74 AM |
164 | void __weak arch_release_task_struct(struct task_struct *tsk) |
165 | { | |
166 | } | |
167 | ||
f5e10287 | 168 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 169 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
170 | |
171 | static inline struct task_struct *alloc_task_struct_node(int node) | |
172 | { | |
173 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
174 | } | |
175 | ||
41101809 TG |
176 | static inline void free_task_struct(struct task_struct *tsk) |
177 | { | |
41101809 TG |
178 | kmem_cache_free(task_struct_cachep, tsk); |
179 | } | |
1da177e4 LT |
180 | #endif |
181 | ||
b235beea | 182 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 183 | |
0d15d74a TG |
184 | /* |
185 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
186 | * kmemcache based allocator. | |
187 | */ | |
ba14a194 | 188 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) |
ac496bf4 | 189 | |
be9a2277 | 190 | # ifdef CONFIG_VMAP_STACK |
ac496bf4 AL |
191 | /* |
192 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB | |
193 | * flush. Try to minimize the number of calls by caching stacks. | |
194 | */ | |
195 | #define NR_CACHED_STACKS 2 | |
196 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); | |
19659c59 | 197 | |
e540bf31 SAS |
198 | struct vm_stack { |
199 | struct rcu_head rcu; | |
200 | struct vm_struct *stack_vm_area; | |
201 | }; | |
202 | ||
203 | static bool try_release_thread_stack_to_cache(struct vm_struct *vm) | |
204 | { | |
205 | unsigned int i; | |
206 | ||
207 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
208 | if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL) | |
209 | continue; | |
210 | return true; | |
211 | } | |
212 | return false; | |
213 | } | |
214 | ||
215 | static void thread_stack_free_rcu(struct rcu_head *rh) | |
216 | { | |
217 | struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu); | |
218 | ||
219 | if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area)) | |
220 | return; | |
221 | ||
222 | vfree(vm_stack); | |
223 | } | |
224 | ||
225 | static void thread_stack_delayed_free(struct task_struct *tsk) | |
226 | { | |
227 | struct vm_stack *vm_stack = tsk->stack; | |
228 | ||
229 | vm_stack->stack_vm_area = tsk->stack_vm_area; | |
230 | call_rcu(&vm_stack->rcu, thread_stack_free_rcu); | |
231 | } | |
232 | ||
19659c59 HR |
233 | static int free_vm_stack_cache(unsigned int cpu) |
234 | { | |
235 | struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); | |
236 | int i; | |
237 | ||
238 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
239 | struct vm_struct *vm_stack = cached_vm_stacks[i]; | |
240 | ||
241 | if (!vm_stack) | |
242 | continue; | |
243 | ||
244 | vfree(vm_stack->addr); | |
245 | cached_vm_stacks[i] = NULL; | |
246 | } | |
247 | ||
248 | return 0; | |
249 | } | |
ac496bf4 | 250 | |
1a03d3f1 | 251 | static int memcg_charge_kernel_stack(struct vm_struct *vm) |
b69c49b7 | 252 | { |
f1c1a9ee SAS |
253 | int i; |
254 | int ret; | |
4e2f6342 | 255 | int nr_charged = 0; |
f1c1a9ee | 256 | |
f1c1a9ee SAS |
257 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); |
258 | ||
259 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { | |
260 | ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0); | |
261 | if (ret) | |
262 | goto err; | |
4e2f6342 | 263 | nr_charged++; |
f1c1a9ee SAS |
264 | } |
265 | return 0; | |
266 | err: | |
4e2f6342 | 267 | for (i = 0; i < nr_charged; i++) |
f1c1a9ee SAS |
268 | memcg_kmem_uncharge_page(vm->pages[i], 0); |
269 | return ret; | |
270 | } | |
271 | ||
7865aba3 | 272 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
b69c49b7 | 273 | { |
1a03d3f1 | 274 | struct vm_struct *vm; |
ac496bf4 AL |
275 | void *stack; |
276 | int i; | |
277 | ||
ac496bf4 | 278 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
279 | struct vm_struct *s; |
280 | ||
281 | s = this_cpu_xchg(cached_stacks[i], NULL); | |
ac496bf4 AL |
282 | |
283 | if (!s) | |
284 | continue; | |
ac496bf4 | 285 | |
51fb34de | 286 | /* Reset stack metadata. */ |
cebd0eb2 | 287 | kasan_unpoison_range(s->addr, THREAD_SIZE); |
eafb149e | 288 | |
51fb34de AK |
289 | stack = kasan_reset_tag(s->addr); |
290 | ||
ca182551 | 291 | /* Clear stale pointers from reused stack. */ |
51fb34de | 292 | memset(stack, 0, THREAD_SIZE); |
e01e8063 | 293 | |
1a03d3f1 | 294 | if (memcg_charge_kernel_stack(s)) { |
f1c1a9ee SAS |
295 | vfree(s->addr); |
296 | return -ENOMEM; | |
297 | } | |
298 | ||
ac496bf4 | 299 | tsk->stack_vm_area = s; |
51fb34de | 300 | tsk->stack = stack; |
7865aba3 | 301 | return 0; |
ac496bf4 | 302 | } |
ac496bf4 | 303 | |
9b6f7e16 RG |
304 | /* |
305 | * Allocated stacks are cached and later reused by new threads, | |
306 | * so memcg accounting is performed manually on assigning/releasing | |
307 | * stacks to tasks. Drop __GFP_ACCOUNT. | |
308 | */ | |
48ac3c18 | 309 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, |
ac496bf4 | 310 | VMALLOC_START, VMALLOC_END, |
9b6f7e16 | 311 | THREADINFO_GFP & ~__GFP_ACCOUNT, |
ac496bf4 AL |
312 | PAGE_KERNEL, |
313 | 0, node, __builtin_return_address(0)); | |
7865aba3 SAS |
314 | if (!stack) |
315 | return -ENOMEM; | |
ba14a194 | 316 | |
1a03d3f1 SAS |
317 | vm = find_vm_area(stack); |
318 | if (memcg_charge_kernel_stack(vm)) { | |
f1c1a9ee SAS |
319 | vfree(stack); |
320 | return -ENOMEM; | |
321 | } | |
ba14a194 AL |
322 | /* |
323 | * We can't call find_vm_area() in interrupt context, and | |
324 | * free_thread_stack() can be called in interrupt context, | |
325 | * so cache the vm_struct. | |
326 | */ | |
1a03d3f1 | 327 | tsk->stack_vm_area = vm; |
51fb34de | 328 | stack = kasan_reset_tag(stack); |
7865aba3 SAS |
329 | tsk->stack = stack; |
330 | return 0; | |
b69c49b7 FT |
331 | } |
332 | ||
be9a2277 | 333 | static void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 334 | { |
e540bf31 SAS |
335 | if (!try_release_thread_stack_to_cache(tsk->stack_vm_area)) |
336 | thread_stack_delayed_free(tsk); | |
9b6f7e16 | 337 | |
be9a2277 SAS |
338 | tsk->stack = NULL; |
339 | tsk->stack_vm_area = NULL; | |
340 | } | |
ac496bf4 | 341 | |
be9a2277 | 342 | # else /* !CONFIG_VMAP_STACK */ |
ac496bf4 | 343 | |
e540bf31 SAS |
344 | static void thread_stack_free_rcu(struct rcu_head *rh) |
345 | { | |
346 | __free_pages(virt_to_page(rh), THREAD_SIZE_ORDER); | |
347 | } | |
348 | ||
349 | static void thread_stack_delayed_free(struct task_struct *tsk) | |
350 | { | |
351 | struct rcu_head *rh = tsk->stack; | |
352 | ||
353 | call_rcu(rh, thread_stack_free_rcu); | |
354 | } | |
355 | ||
7865aba3 | 356 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
be9a2277 | 357 | { |
4949148a VD |
358 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
359 | THREAD_SIZE_ORDER); | |
b6a84016 | 360 | |
1bf4580e | 361 | if (likely(page)) { |
8dcc1d34 | 362 | tsk->stack = kasan_reset_tag(page_address(page)); |
7865aba3 | 363 | return 0; |
1bf4580e | 364 | } |
7865aba3 | 365 | return -ENOMEM; |
b69c49b7 FT |
366 | } |
367 | ||
be9a2277 | 368 | static void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 369 | { |
e540bf31 | 370 | thread_stack_delayed_free(tsk); |
be9a2277 | 371 | tsk->stack = NULL; |
b69c49b7 | 372 | } |
ac496bf4 | 373 | |
be9a2277 SAS |
374 | # endif /* CONFIG_VMAP_STACK */ |
375 | # else /* !(THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)) */ | |
9b6f7e16 | 376 | |
b235beea | 377 | static struct kmem_cache *thread_stack_cache; |
ac496bf4 | 378 | |
e540bf31 SAS |
379 | static void thread_stack_free_rcu(struct rcu_head *rh) |
380 | { | |
381 | kmem_cache_free(thread_stack_cache, rh); | |
382 | } | |
ac496bf4 | 383 | |
e540bf31 SAS |
384 | static void thread_stack_delayed_free(struct task_struct *tsk) |
385 | { | |
386 | struct rcu_head *rh = tsk->stack; | |
ac496bf4 | 387 | |
e540bf31 | 388 | call_rcu(rh, thread_stack_free_rcu); |
b69c49b7 | 389 | } |
0d15d74a | 390 | |
7865aba3 | 391 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
0d15d74a | 392 | { |
5eed6f1d RR |
393 | unsigned long *stack; |
394 | stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); | |
8dcc1d34 | 395 | stack = kasan_reset_tag(stack); |
5eed6f1d | 396 | tsk->stack = stack; |
7865aba3 | 397 | return stack ? 0 : -ENOMEM; |
0d15d74a TG |
398 | } |
399 | ||
ba14a194 | 400 | static void free_thread_stack(struct task_struct *tsk) |
0d15d74a | 401 | { |
e540bf31 | 402 | thread_stack_delayed_free(tsk); |
be9a2277 | 403 | tsk->stack = NULL; |
0d15d74a TG |
404 | } |
405 | ||
b235beea | 406 | void thread_stack_cache_init(void) |
0d15d74a | 407 | { |
f9d29946 DW |
408 | thread_stack_cache = kmem_cache_create_usercopy("thread_stack", |
409 | THREAD_SIZE, THREAD_SIZE, 0, 0, | |
410 | THREAD_SIZE, NULL); | |
b235beea | 411 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a | 412 | } |
be9a2277 SAS |
413 | |
414 | # endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */ | |
2bb0529c SAS |
415 | #else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */ |
416 | ||
7865aba3 | 417 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
2bb0529c SAS |
418 | { |
419 | unsigned long *stack; | |
420 | ||
421 | stack = arch_alloc_thread_stack_node(tsk, node); | |
422 | tsk->stack = stack; | |
7865aba3 | 423 | return stack ? 0 : -ENOMEM; |
2bb0529c SAS |
424 | } |
425 | ||
426 | static void free_thread_stack(struct task_struct *tsk) | |
427 | { | |
428 | arch_free_thread_stack(tsk); | |
429 | tsk->stack = NULL; | |
430 | } | |
431 | ||
be9a2277 | 432 | #endif /* !CONFIG_ARCH_THREAD_STACK_ALLOCATOR */ |
b69c49b7 | 433 | |
1da177e4 | 434 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 435 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
436 | |
437 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 438 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
439 | |
440 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 441 | struct kmem_cache *files_cachep; |
1da177e4 LT |
442 | |
443 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 444 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
445 | |
446 | /* SLAB cache for vm_area_struct structures */ | |
3928d4f5 | 447 | static struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
448 | |
449 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 450 | static struct kmem_cache *mm_cachep; |
1da177e4 | 451 | |
c7f8f31c SB |
452 | #ifdef CONFIG_PER_VMA_LOCK |
453 | ||
454 | /* SLAB cache for vm_area_struct.lock */ | |
455 | static struct kmem_cache *vma_lock_cachep; | |
456 | ||
457 | static bool vma_lock_alloc(struct vm_area_struct *vma) | |
458 | { | |
459 | vma->vm_lock = kmem_cache_alloc(vma_lock_cachep, GFP_KERNEL); | |
460 | if (!vma->vm_lock) | |
461 | return false; | |
462 | ||
463 | init_rwsem(&vma->vm_lock->lock); | |
464 | vma->vm_lock_seq = -1; | |
465 | ||
466 | return true; | |
467 | } | |
468 | ||
469 | static inline void vma_lock_free(struct vm_area_struct *vma) | |
470 | { | |
471 | kmem_cache_free(vma_lock_cachep, vma->vm_lock); | |
472 | } | |
473 | ||
474 | #else /* CONFIG_PER_VMA_LOCK */ | |
475 | ||
476 | static inline bool vma_lock_alloc(struct vm_area_struct *vma) { return true; } | |
477 | static inline void vma_lock_free(struct vm_area_struct *vma) {} | |
478 | ||
479 | #endif /* CONFIG_PER_VMA_LOCK */ | |
480 | ||
490fc053 | 481 | struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) |
3928d4f5 | 482 | { |
a670468f | 483 | struct vm_area_struct *vma; |
490fc053 | 484 | |
a670468f | 485 | vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
c7f8f31c SB |
486 | if (!vma) |
487 | return NULL; | |
488 | ||
489 | vma_init(vma, mm); | |
490 | if (!vma_lock_alloc(vma)) { | |
491 | kmem_cache_free(vm_area_cachep, vma); | |
492 | return NULL; | |
493 | } | |
494 | ||
490fc053 | 495 | return vma; |
3928d4f5 LT |
496 | } |
497 | ||
498 | struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) | |
499 | { | |
95faf699 LT |
500 | struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
501 | ||
c7f8f31c SB |
502 | if (!new) |
503 | return NULL; | |
504 | ||
505 | ASSERT_EXCLUSIVE_WRITER(orig->vm_flags); | |
506 | ASSERT_EXCLUSIVE_WRITER(orig->vm_file); | |
507 | /* | |
508 | * orig->shared.rb may be modified concurrently, but the clone | |
509 | * will be reinitialized. | |
510 | */ | |
511 | data_race(memcpy(new, orig, sizeof(*new))); | |
512 | if (!vma_lock_alloc(new)) { | |
513 | kmem_cache_free(vm_area_cachep, new); | |
514 | return NULL; | |
95faf699 | 515 | } |
c7f8f31c | 516 | INIT_LIST_HEAD(&new->anon_vma_chain); |
ef6a22b7 | 517 | vma_numab_state_init(new); |
c7f8f31c SB |
518 | dup_anon_vma_name(orig, new); |
519 | ||
95faf699 | 520 | return new; |
3928d4f5 LT |
521 | } |
522 | ||
0d2ebf9c | 523 | void __vm_area_free(struct vm_area_struct *vma) |
3928d4f5 | 524 | { |
ef6a22b7 | 525 | vma_numab_state_free(vma); |
5c26f6ac | 526 | free_anon_vma_name(vma); |
c7f8f31c | 527 | vma_lock_free(vma); |
3928d4f5 LT |
528 | kmem_cache_free(vm_area_cachep, vma); |
529 | } | |
530 | ||
20cce633 ML |
531 | #ifdef CONFIG_PER_VMA_LOCK |
532 | static void vm_area_free_rcu_cb(struct rcu_head *head) | |
533 | { | |
534 | struct vm_area_struct *vma = container_of(head, struct vm_area_struct, | |
535 | vm_rcu); | |
f2e13784 SB |
536 | |
537 | /* The vma should not be locked while being destroyed. */ | |
c7f8f31c | 538 | VM_BUG_ON_VMA(rwsem_is_locked(&vma->vm_lock->lock), vma); |
20cce633 ML |
539 | __vm_area_free(vma); |
540 | } | |
541 | #endif | |
542 | ||
543 | void vm_area_free(struct vm_area_struct *vma) | |
544 | { | |
545 | #ifdef CONFIG_PER_VMA_LOCK | |
546 | call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb); | |
547 | #else | |
548 | __vm_area_free(vma); | |
549 | #endif | |
550 | } | |
551 | ||
ba14a194 | 552 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 553 | { |
0ce055f8 SAS |
554 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
555 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
27faca83 | 556 | int i; |
ba14a194 | 557 | |
27faca83 MS |
558 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) |
559 | mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB, | |
560 | account * (PAGE_SIZE / 1024)); | |
561 | } else { | |
0ce055f8 SAS |
562 | void *stack = task_stack_page(tsk); |
563 | ||
27faca83 | 564 | /* All stack pages are in the same node. */ |
da3ceeff | 565 | mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB, |
991e7673 | 566 | account * (THREAD_SIZE / 1024)); |
27faca83 | 567 | } |
c6a7f572 KM |
568 | } |
569 | ||
1a03d3f1 | 570 | void exit_task_stack_account(struct task_struct *tsk) |
9b6f7e16 | 571 | { |
1a03d3f1 | 572 | account_kernel_stack(tsk, -1); |
991e7673 | 573 | |
1a03d3f1 SAS |
574 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
575 | struct vm_struct *vm; | |
9b6f7e16 RG |
576 | int i; |
577 | ||
1a03d3f1 SAS |
578 | vm = task_stack_vm_area(tsk); |
579 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) | |
580 | memcg_kmem_uncharge_page(vm->pages[i], 0); | |
9b6f7e16 | 581 | } |
9b6f7e16 RG |
582 | } |
583 | ||
68f24b08 | 584 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 585 | { |
2f064a59 | 586 | if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD)) |
405c0759 AL |
587 | return; /* Better to leak the stack than to free prematurely */ |
588 | ||
ba14a194 | 589 | free_thread_stack(tsk); |
68f24b08 AL |
590 | } |
591 | ||
592 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
593 | void put_task_stack(struct task_struct *tsk) | |
594 | { | |
f0b89d39 | 595 | if (refcount_dec_and_test(&tsk->stack_refcount)) |
68f24b08 AL |
596 | release_task_stack(tsk); |
597 | } | |
598 | #endif | |
599 | ||
600 | void free_task(struct task_struct *tsk) | |
601 | { | |
a1140cb2 KI |
602 | #ifdef CONFIG_SECCOMP |
603 | WARN_ON_ONCE(tsk->seccomp.filter); | |
604 | #endif | |
b90ca8ba | 605 | release_user_cpus_ptr(tsk); |
d08b9f0c ST |
606 | scs_release(tsk); |
607 | ||
68f24b08 AL |
608 | #ifndef CONFIG_THREAD_INFO_IN_TASK |
609 | /* | |
610 | * The task is finally done with both the stack and thread_info, | |
611 | * so free both. | |
612 | */ | |
613 | release_task_stack(tsk); | |
614 | #else | |
615 | /* | |
616 | * If the task had a separate stack allocation, it should be gone | |
617 | * by now. | |
618 | */ | |
f0b89d39 | 619 | WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0); |
68f24b08 | 620 | #endif |
23f78d4a | 621 | rt_mutex_debug_task_free(tsk); |
fb52607a | 622 | ftrace_graph_exit_task(tsk); |
f19b9f74 | 623 | arch_release_task_struct(tsk); |
1da5c46f ON |
624 | if (tsk->flags & PF_KTHREAD) |
625 | free_kthread_struct(tsk); | |
b0fd1852 | 626 | bpf_task_storage_free(tsk); |
1da177e4 LT |
627 | free_task_struct(tsk); |
628 | } | |
629 | EXPORT_SYMBOL(free_task); | |
630 | ||
fe69d560 DH |
631 | static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm) |
632 | { | |
633 | struct file *exe_file; | |
634 | ||
635 | exe_file = get_mm_exe_file(oldmm); | |
636 | RCU_INIT_POINTER(mm->exe_file, exe_file); | |
637 | /* | |
638 | * We depend on the oldmm having properly denied write access to the | |
639 | * exe_file already. | |
640 | */ | |
641 | if (exe_file && deny_write_access(exe_file)) | |
642 | pr_warn_once("deny_write_access() failed in %s\n", __func__); | |
643 | } | |
644 | ||
d70f2a14 AM |
645 | #ifdef CONFIG_MMU |
646 | static __latent_entropy int dup_mmap(struct mm_struct *mm, | |
647 | struct mm_struct *oldmm) | |
648 | { | |
763ecb03 | 649 | struct vm_area_struct *mpnt, *tmp; |
d70f2a14 | 650 | int retval; |
c9dbe82c | 651 | unsigned long charge = 0; |
d70f2a14 | 652 | LIST_HEAD(uf); |
3b9dbd5e LH |
653 | VMA_ITERATOR(old_vmi, oldmm, 0); |
654 | VMA_ITERATOR(vmi, mm, 0); | |
d70f2a14 AM |
655 | |
656 | uprobe_start_dup_mmap(); | |
d8ed45c5 | 657 | if (mmap_write_lock_killable(oldmm)) { |
d70f2a14 AM |
658 | retval = -EINTR; |
659 | goto fail_uprobe_end; | |
660 | } | |
661 | flush_cache_dup_mm(oldmm); | |
662 | uprobe_dup_mmap(oldmm, mm); | |
663 | /* | |
664 | * Not linked in yet - no deadlock potential: | |
665 | */ | |
aaa2cc56 | 666 | mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING); |
d70f2a14 AM |
667 | |
668 | /* No ordering required: file already has been exposed. */ | |
fe69d560 | 669 | dup_mm_exe_file(mm, oldmm); |
d70f2a14 AM |
670 | |
671 | mm->total_vm = oldmm->total_vm; | |
672 | mm->data_vm = oldmm->data_vm; | |
673 | mm->exec_vm = oldmm->exec_vm; | |
674 | mm->stack_vm = oldmm->stack_vm; | |
675 | ||
d70f2a14 AM |
676 | retval = ksm_fork(mm, oldmm); |
677 | if (retval) | |
678 | goto out; | |
d2081b2b | 679 | khugepaged_fork(mm, oldmm); |
d70f2a14 | 680 | |
3b9dbd5e | 681 | retval = vma_iter_bulk_alloc(&vmi, oldmm->map_count); |
c9dbe82c LH |
682 | if (retval) |
683 | goto out; | |
684 | ||
3dd44325 | 685 | mt_clear_in_rcu(vmi.mas.tree); |
3b9dbd5e | 686 | for_each_vma(old_vmi, mpnt) { |
d70f2a14 AM |
687 | struct file *file; |
688 | ||
fb49c455 | 689 | vma_start_write(mpnt); |
d70f2a14 AM |
690 | if (mpnt->vm_flags & VM_DONTCOPY) { |
691 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); | |
692 | continue; | |
693 | } | |
694 | charge = 0; | |
655c79bb TH |
695 | /* |
696 | * Don't duplicate many vmas if we've been oom-killed (for | |
697 | * example) | |
698 | */ | |
699 | if (fatal_signal_pending(current)) { | |
700 | retval = -EINTR; | |
d4af56c5 | 701 | goto loop_out; |
655c79bb | 702 | } |
d70f2a14 AM |
703 | if (mpnt->vm_flags & VM_ACCOUNT) { |
704 | unsigned long len = vma_pages(mpnt); | |
705 | ||
706 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ | |
707 | goto fail_nomem; | |
708 | charge = len; | |
709 | } | |
3928d4f5 | 710 | tmp = vm_area_dup(mpnt); |
d70f2a14 AM |
711 | if (!tmp) |
712 | goto fail_nomem; | |
d70f2a14 AM |
713 | retval = vma_dup_policy(mpnt, tmp); |
714 | if (retval) | |
715 | goto fail_nomem_policy; | |
716 | tmp->vm_mm = mm; | |
717 | retval = dup_userfaultfd(tmp, &uf); | |
718 | if (retval) | |
719 | goto fail_nomem_anon_vma_fork; | |
720 | if (tmp->vm_flags & VM_WIPEONFORK) { | |
93949bb2 LX |
721 | /* |
722 | * VM_WIPEONFORK gets a clean slate in the child. | |
723 | * Don't prepare anon_vma until fault since we don't | |
724 | * copy page for current vma. | |
725 | */ | |
d70f2a14 | 726 | tmp->anon_vma = NULL; |
d70f2a14 AM |
727 | } else if (anon_vma_fork(tmp, mpnt)) |
728 | goto fail_nomem_anon_vma_fork; | |
e430a95a | 729 | vm_flags_clear(tmp, VM_LOCKED_MASK); |
d70f2a14 AM |
730 | file = tmp->vm_file; |
731 | if (file) { | |
d70f2a14 AM |
732 | struct address_space *mapping = file->f_mapping; |
733 | ||
734 | get_file(file); | |
d70f2a14 | 735 | i_mmap_lock_write(mapping); |
e8e17ee9 | 736 | if (vma_is_shared_maywrite(tmp)) |
cf508b58 | 737 | mapping_allow_writable(mapping); |
d70f2a14 AM |
738 | flush_dcache_mmap_lock(mapping); |
739 | /* insert tmp into the share list, just after mpnt */ | |
740 | vma_interval_tree_insert_after(tmp, mpnt, | |
741 | &mapping->i_mmap); | |
742 | flush_dcache_mmap_unlock(mapping); | |
743 | i_mmap_unlock_write(mapping); | |
744 | } | |
745 | ||
746 | /* | |
8d9bfb26 | 747 | * Copy/update hugetlb private vma information. |
d70f2a14 AM |
748 | */ |
749 | if (is_vm_hugetlb_page(tmp)) | |
8d9bfb26 | 750 | hugetlb_dup_vma_private(tmp); |
d70f2a14 | 751 | |
d4af56c5 | 752 | /* Link the vma into the MT */ |
3b9dbd5e LH |
753 | if (vma_iter_bulk_store(&vmi, tmp)) |
754 | goto fail_nomem_vmi_store; | |
d70f2a14 AM |
755 | |
756 | mm->map_count++; | |
757 | if (!(tmp->vm_flags & VM_WIPEONFORK)) | |
c78f4636 | 758 | retval = copy_page_range(tmp, mpnt); |
d70f2a14 AM |
759 | |
760 | if (tmp->vm_ops && tmp->vm_ops->open) | |
761 | tmp->vm_ops->open(tmp); | |
762 | ||
763 | if (retval) | |
d4af56c5 | 764 | goto loop_out; |
d70f2a14 AM |
765 | } |
766 | /* a new mm has just been created */ | |
1ed0cc5a | 767 | retval = arch_dup_mmap(oldmm, mm); |
d4af56c5 | 768 | loop_out: |
3b9dbd5e | 769 | vma_iter_free(&vmi); |
3dd44325 LH |
770 | if (!retval) |
771 | mt_set_in_rcu(vmi.mas.tree); | |
d70f2a14 | 772 | out: |
d8ed45c5 | 773 | mmap_write_unlock(mm); |
d70f2a14 | 774 | flush_tlb_mm(oldmm); |
d8ed45c5 | 775 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
776 | dup_userfaultfd_complete(&uf); |
777 | fail_uprobe_end: | |
778 | uprobe_end_dup_mmap(); | |
779 | return retval; | |
c9dbe82c | 780 | |
3b9dbd5e | 781 | fail_nomem_vmi_store: |
c9dbe82c | 782 | unlink_anon_vmas(tmp); |
d70f2a14 AM |
783 | fail_nomem_anon_vma_fork: |
784 | mpol_put(vma_policy(tmp)); | |
785 | fail_nomem_policy: | |
3928d4f5 | 786 | vm_area_free(tmp); |
d70f2a14 AM |
787 | fail_nomem: |
788 | retval = -ENOMEM; | |
789 | vm_unacct_memory(charge); | |
d4af56c5 | 790 | goto loop_out; |
d70f2a14 AM |
791 | } |
792 | ||
793 | static inline int mm_alloc_pgd(struct mm_struct *mm) | |
794 | { | |
795 | mm->pgd = pgd_alloc(mm); | |
796 | if (unlikely(!mm->pgd)) | |
797 | return -ENOMEM; | |
798 | return 0; | |
799 | } | |
800 | ||
801 | static inline void mm_free_pgd(struct mm_struct *mm) | |
802 | { | |
803 | pgd_free(mm, mm->pgd); | |
804 | } | |
805 | #else | |
806 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) | |
807 | { | |
d8ed45c5 | 808 | mmap_write_lock(oldmm); |
fe69d560 | 809 | dup_mm_exe_file(mm, oldmm); |
d8ed45c5 | 810 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
811 | return 0; |
812 | } | |
813 | #define mm_alloc_pgd(mm) (0) | |
814 | #define mm_free_pgd(mm) | |
815 | #endif /* CONFIG_MMU */ | |
816 | ||
817 | static void check_mm(struct mm_struct *mm) | |
818 | { | |
819 | int i; | |
820 | ||
8495f7e6 SPP |
821 | BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS, |
822 | "Please make sure 'struct resident_page_types[]' is updated as well"); | |
823 | ||
d70f2a14 | 824 | for (i = 0; i < NR_MM_COUNTERS; i++) { |
f1a79412 | 825 | long x = percpu_counter_sum(&mm->rss_stat[i]); |
d70f2a14 AM |
826 | |
827 | if (unlikely(x)) | |
8495f7e6 SPP |
828 | pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n", |
829 | mm, resident_page_types[i], x); | |
d70f2a14 AM |
830 | } |
831 | ||
832 | if (mm_pgtables_bytes(mm)) | |
833 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", | |
834 | mm_pgtables_bytes(mm)); | |
835 | ||
836 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
837 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); | |
838 | #endif | |
839 | } | |
840 | ||
841 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) | |
842 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
843 | ||
2655421a NP |
844 | static void do_check_lazy_tlb(void *arg) |
845 | { | |
846 | struct mm_struct *mm = arg; | |
847 | ||
848 | WARN_ON_ONCE(current->active_mm == mm); | |
849 | } | |
850 | ||
851 | static void do_shoot_lazy_tlb(void *arg) | |
852 | { | |
853 | struct mm_struct *mm = arg; | |
854 | ||
855 | if (current->active_mm == mm) { | |
856 | WARN_ON_ONCE(current->mm); | |
857 | current->active_mm = &init_mm; | |
858 | switch_mm(mm, &init_mm, current); | |
859 | } | |
860 | } | |
861 | ||
862 | static void cleanup_lazy_tlbs(struct mm_struct *mm) | |
863 | { | |
864 | if (!IS_ENABLED(CONFIG_MMU_LAZY_TLB_SHOOTDOWN)) { | |
865 | /* | |
866 | * In this case, lazy tlb mms are refounted and would not reach | |
867 | * __mmdrop until all CPUs have switched away and mmdrop()ed. | |
868 | */ | |
869 | return; | |
870 | } | |
871 | ||
872 | /* | |
873 | * Lazy mm shootdown does not refcount "lazy tlb mm" usage, rather it | |
874 | * requires lazy mm users to switch to another mm when the refcount | |
875 | * drops to zero, before the mm is freed. This requires IPIs here to | |
876 | * switch kernel threads to init_mm. | |
877 | * | |
878 | * archs that use IPIs to flush TLBs can piggy-back that lazy tlb mm | |
879 | * switch with the final userspace teardown TLB flush which leaves the | |
880 | * mm lazy on this CPU but no others, reducing the need for additional | |
881 | * IPIs here. There are cases where a final IPI is still required here, | |
882 | * such as the final mmdrop being performed on a different CPU than the | |
883 | * one exiting, or kernel threads using the mm when userspace exits. | |
884 | * | |
885 | * IPI overheads have not found to be expensive, but they could be | |
886 | * reduced in a number of possible ways, for example (roughly | |
887 | * increasing order of complexity): | |
888 | * - The last lazy reference created by exit_mm() could instead switch | |
889 | * to init_mm, however it's probable this will run on the same CPU | |
890 | * immediately afterwards, so this may not reduce IPIs much. | |
891 | * - A batch of mms requiring IPIs could be gathered and freed at once. | |
892 | * - CPUs store active_mm where it can be remotely checked without a | |
893 | * lock, to filter out false-positives in the cpumask. | |
894 | * - After mm_users or mm_count reaches zero, switching away from the | |
895 | * mm could clear mm_cpumask to reduce some IPIs, perhaps together | |
896 | * with some batching or delaying of the final IPIs. | |
897 | * - A delayed freeing and RCU-like quiescing sequence based on mm | |
898 | * switching to avoid IPIs completely. | |
899 | */ | |
900 | on_each_cpu_mask(mm_cpumask(mm), do_shoot_lazy_tlb, (void *)mm, 1); | |
901 | if (IS_ENABLED(CONFIG_DEBUG_VM_SHOOT_LAZIES)) | |
902 | on_each_cpu(do_check_lazy_tlb, (void *)mm, 1); | |
903 | } | |
904 | ||
d70f2a14 AM |
905 | /* |
906 | * Called when the last reference to the mm | |
907 | * is dropped: either by a lazy thread or by | |
908 | * mmput. Free the page directory and the mm. | |
909 | */ | |
d34bc48f | 910 | void __mmdrop(struct mm_struct *mm) |
d70f2a14 AM |
911 | { |
912 | BUG_ON(mm == &init_mm); | |
3eda69c9 | 913 | WARN_ON_ONCE(mm == current->mm); |
2655421a NP |
914 | |
915 | /* Ensure no CPUs are using this as their lazy tlb mm */ | |
916 | cleanup_lazy_tlbs(mm); | |
917 | ||
3eda69c9 | 918 | WARN_ON_ONCE(mm == current->active_mm); |
d70f2a14 AM |
919 | mm_free_pgd(mm); |
920 | destroy_context(mm); | |
984cfe4e | 921 | mmu_notifier_subscriptions_destroy(mm); |
d70f2a14 AM |
922 | check_mm(mm); |
923 | put_user_ns(mm->user_ns); | |
2667ed10 | 924 | mm_pasid_drop(mm); |
223baf9d | 925 | mm_destroy_cid(mm); |
14ef95be | 926 | percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS); |
f1a79412 | 927 | |
d70f2a14 AM |
928 | free_mm(mm); |
929 | } | |
d34bc48f | 930 | EXPORT_SYMBOL_GPL(__mmdrop); |
d70f2a14 AM |
931 | |
932 | static void mmdrop_async_fn(struct work_struct *work) | |
933 | { | |
934 | struct mm_struct *mm; | |
935 | ||
936 | mm = container_of(work, struct mm_struct, async_put_work); | |
937 | __mmdrop(mm); | |
938 | } | |
939 | ||
940 | static void mmdrop_async(struct mm_struct *mm) | |
941 | { | |
942 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) { | |
943 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn); | |
944 | schedule_work(&mm->async_put_work); | |
945 | } | |
946 | } | |
947 | ||
ea6d290c ON |
948 | static inline void free_signal_struct(struct signal_struct *sig) |
949 | { | |
97101eb4 | 950 | taskstats_tgid_free(sig); |
1c5354de | 951 | sched_autogroup_exit(sig); |
7283094e MH |
952 | /* |
953 | * __mmdrop is not safe to call from softirq context on x86 due to | |
954 | * pgd_dtor so postpone it to the async context | |
955 | */ | |
26db62f1 | 956 | if (sig->oom_mm) |
7283094e | 957 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
958 | kmem_cache_free(signal_cachep, sig); |
959 | } | |
960 | ||
961 | static inline void put_signal_struct(struct signal_struct *sig) | |
962 | { | |
60d4de3f | 963 | if (refcount_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
964 | free_signal_struct(sig); |
965 | } | |
966 | ||
158d9ebd | 967 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 968 | { |
270f722d | 969 | WARN_ON(!tsk->exit_state); |
ec1d2819 | 970 | WARN_ON(refcount_read(&tsk->usage)); |
1da177e4 LT |
971 | WARN_ON(tsk == current); |
972 | ||
0f212204 | 973 | io_uring_free(tsk); |
2e91fa7f | 974 | cgroup_free(tsk); |
16d51a59 | 975 | task_numa_free(tsk, true); |
1a2a4d06 | 976 | security_task_free(tsk); |
e0e81739 | 977 | exit_creds(tsk); |
35df17c5 | 978 | delayacct_tsk_free(tsk); |
ea6d290c | 979 | put_signal_struct(tsk->signal); |
6e33cad0 | 980 | sched_core_free(tsk); |
2873cd31 | 981 | free_task(tsk); |
1da177e4 | 982 | } |
77c100c8 | 983 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 984 | |
d243b344 WLC |
985 | void __put_task_struct_rcu_cb(struct rcu_head *rhp) |
986 | { | |
987 | struct task_struct *task = container_of(rhp, struct task_struct, rcu); | |
988 | ||
989 | __put_task_struct(task); | |
990 | } | |
991 | EXPORT_SYMBOL_GPL(__put_task_struct_rcu_cb); | |
992 | ||
6c0a9fa6 | 993 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 994 | |
ff691f6e HS |
995 | /* |
996 | * set_max_threads | |
997 | */ | |
16db3d3f | 998 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 999 | { |
ac1b398d | 1000 | u64 threads; |
ca79b0c2 | 1001 | unsigned long nr_pages = totalram_pages(); |
ff691f6e HS |
1002 | |
1003 | /* | |
ac1b398d HS |
1004 | * The number of threads shall be limited such that the thread |
1005 | * structures may only consume a small part of the available memory. | |
ff691f6e | 1006 | */ |
3d6357de | 1007 | if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64) |
ac1b398d HS |
1008 | threads = MAX_THREADS; |
1009 | else | |
3d6357de | 1010 | threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE, |
ac1b398d HS |
1011 | (u64) THREAD_SIZE * 8UL); |
1012 | ||
16db3d3f HS |
1013 | if (threads > max_threads_suggested) |
1014 | threads = max_threads_suggested; | |
1015 | ||
ac1b398d | 1016 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
1017 | } |
1018 | ||
5aaeb5c0 IM |
1019 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
1020 | /* Initialized by the architecture: */ | |
1021 | int arch_task_struct_size __read_mostly; | |
1022 | #endif | |
0c8c0f03 | 1023 | |
4189ff23 | 1024 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
5905429a KC |
1025 | static void task_struct_whitelist(unsigned long *offset, unsigned long *size) |
1026 | { | |
1027 | /* Fetch thread_struct whitelist for the architecture. */ | |
1028 | arch_thread_struct_whitelist(offset, size); | |
1029 | ||
1030 | /* | |
1031 | * Handle zero-sized whitelist or empty thread_struct, otherwise | |
1032 | * adjust offset to position of thread_struct in task_struct. | |
1033 | */ | |
1034 | if (unlikely(*size == 0)) | |
1035 | *offset = 0; | |
1036 | else | |
1037 | *offset += offsetof(struct task_struct, thread); | |
1038 | } | |
4189ff23 | 1039 | #endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */ |
5905429a | 1040 | |
ff691f6e | 1041 | void __init fork_init(void) |
1da177e4 | 1042 | { |
25f9c081 | 1043 | int i; |
f5e10287 | 1044 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 1045 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 1046 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 1047 | #endif |
95cb64c1 | 1048 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
5905429a | 1049 | unsigned long useroffset, usersize; |
e274795e | 1050 | |
1da177e4 | 1051 | /* create a slab on which task_structs can be allocated */ |
5905429a KC |
1052 | task_struct_whitelist(&useroffset, &usersize); |
1053 | task_struct_cachep = kmem_cache_create_usercopy("task_struct", | |
e274795e | 1054 | arch_task_struct_size, align, |
5905429a KC |
1055 | SLAB_PANIC|SLAB_ACCOUNT, |
1056 | useroffset, usersize, NULL); | |
1da177e4 LT |
1057 | #endif |
1058 | ||
61c4628b SS |
1059 | /* do the arch specific task caches init */ |
1060 | arch_task_cache_init(); | |
1061 | ||
16db3d3f | 1062 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
1063 | |
1064 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
1065 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
1066 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
1067 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 1068 | |
de399236 | 1069 | for (i = 0; i < UCOUNT_COUNTS; i++) |
25f9c081 | 1070 | init_user_ns.ucount_max[i] = max_threads/2; |
19659c59 | 1071 | |
de399236 AG |
1072 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); |
1073 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); | |
1074 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); | |
1075 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); | |
21d1c5e3 | 1076 | |
19659c59 HR |
1077 | #ifdef CONFIG_VMAP_STACK |
1078 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", | |
1079 | NULL, free_vm_stack_cache); | |
1080 | #endif | |
b09be676 | 1081 | |
d08b9f0c ST |
1082 | scs_init(); |
1083 | ||
b09be676 | 1084 | lockdep_init_task(&init_task); |
aad42dd4 | 1085 | uprobes_init(); |
1da177e4 LT |
1086 | } |
1087 | ||
52f5684c | 1088 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
1089 | struct task_struct *src) |
1090 | { | |
1091 | *dst = *src; | |
1092 | return 0; | |
1093 | } | |
1094 | ||
d4311ff1 AT |
1095 | void set_task_stack_end_magic(struct task_struct *tsk) |
1096 | { | |
1097 | unsigned long *stackend; | |
1098 | ||
1099 | stackend = end_of_stack(tsk); | |
1100 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1101 | } | |
1102 | ||
725fc629 | 1103 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
1104 | { |
1105 | struct task_struct *tsk; | |
3e26c149 | 1106 | int err; |
1da177e4 | 1107 | |
725fc629 AK |
1108 | if (node == NUMA_NO_NODE) |
1109 | node = tsk_fork_get_node(orig); | |
504f52b5 | 1110 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
1111 | if (!tsk) |
1112 | return NULL; | |
1113 | ||
546c42b2 SAS |
1114 | err = arch_dup_task_struct(tsk, orig); |
1115 | if (err) | |
f19b9f74 | 1116 | goto free_tsk; |
1da177e4 | 1117 | |
7865aba3 SAS |
1118 | err = alloc_thread_stack_node(tsk, node); |
1119 | if (err) | |
f19b9f74 | 1120 | goto free_tsk; |
ba14a194 | 1121 | |
68f24b08 | 1122 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
f0b89d39 | 1123 | refcount_set(&tsk->stack_refcount, 1); |
68f24b08 | 1124 | #endif |
1a03d3f1 | 1125 | account_kernel_stack(tsk, 1); |
164c33c6 | 1126 | |
d08b9f0c ST |
1127 | err = scs_prepare(tsk, node); |
1128 | if (err) | |
1129 | goto free_stack; | |
1130 | ||
dbd95212 KC |
1131 | #ifdef CONFIG_SECCOMP |
1132 | /* | |
1133 | * We must handle setting up seccomp filters once we're under | |
1134 | * the sighand lock in case orig has changed between now and | |
1135 | * then. Until then, filter must be NULL to avoid messing up | |
1136 | * the usage counts on the error path calling free_task. | |
1137 | */ | |
1138 | tsk->seccomp.filter = NULL; | |
1139 | #endif | |
87bec58a AM |
1140 | |
1141 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 1142 | clear_user_return_notifier(tsk); |
f26f9aff | 1143 | clear_tsk_need_resched(tsk); |
d4311ff1 | 1144 | set_task_stack_end_magic(tsk); |
1446e1df | 1145 | clear_syscall_work_syscall_user_dispatch(tsk); |
1da177e4 | 1146 | |
050e9baa | 1147 | #ifdef CONFIG_STACKPROTECTOR |
7cd815bc | 1148 | tsk->stack_canary = get_random_canary(); |
0a425405 | 1149 | #endif |
3bd37062 SAS |
1150 | if (orig->cpus_ptr == &orig->cpus_mask) |
1151 | tsk->cpus_ptr = &tsk->cpus_mask; | |
b90ca8ba | 1152 | dup_user_cpus_ptr(tsk, orig, node); |
0a425405 | 1153 | |
fb0a685c | 1154 | /* |
0ff7b2cf EB |
1155 | * One for the user space visible state that goes away when reaped. |
1156 | * One for the scheduler. | |
fb0a685c | 1157 | */ |
0ff7b2cf EB |
1158 | refcount_set(&tsk->rcu_users, 2); |
1159 | /* One for the rcu users */ | |
1160 | refcount_set(&tsk->usage, 1); | |
6c5c9341 | 1161 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 1162 | tsk->btrace_seq = 0; |
6c5c9341 | 1163 | #endif |
a0aa7f68 | 1164 | tsk->splice_pipe = NULL; |
5640f768 | 1165 | tsk->task_frag.page = NULL; |
093e5840 | 1166 | tsk->wake_q.next = NULL; |
e32cf5df | 1167 | tsk->worker_private = NULL; |
c6a7f572 | 1168 | |
5c9a8750 | 1169 | kcov_task_init(tsk); |
50b5e49c | 1170 | kmsan_task_create(tsk); |
5fbda3ec | 1171 | kmap_local_fork(tsk); |
5c9a8750 | 1172 | |
e41d5818 DV |
1173 | #ifdef CONFIG_FAULT_INJECTION |
1174 | tsk->fail_nth = 0; | |
1175 | #endif | |
1176 | ||
2c323017 | 1177 | #ifdef CONFIG_BLK_CGROUP |
f05837ed | 1178 | tsk->throttle_disk = NULL; |
2c323017 JB |
1179 | tsk->use_memdelay = 0; |
1180 | #endif | |
1181 | ||
a3d29e82 PZ |
1182 | #ifdef CONFIG_IOMMU_SVA |
1183 | tsk->pasid_activated = 0; | |
1184 | #endif | |
1185 | ||
d46eb14b SB |
1186 | #ifdef CONFIG_MEMCG |
1187 | tsk->active_memcg = NULL; | |
1188 | #endif | |
b041b525 TL |
1189 | |
1190 | #ifdef CONFIG_CPU_SUP_INTEL | |
1191 | tsk->reported_split_lock = 0; | |
1192 | #endif | |
1193 | ||
af7f588d MD |
1194 | #ifdef CONFIG_SCHED_MM_CID |
1195 | tsk->mm_cid = -1; | |
223baf9d | 1196 | tsk->last_mm_cid = -1; |
af7f588d | 1197 | tsk->mm_cid_active = 0; |
223baf9d | 1198 | tsk->migrate_from_cpu = -1; |
af7f588d | 1199 | #endif |
1da177e4 | 1200 | return tsk; |
61c4628b | 1201 | |
b235beea | 1202 | free_stack: |
1a03d3f1 | 1203 | exit_task_stack_account(tsk); |
ba14a194 | 1204 | free_thread_stack(tsk); |
f19b9f74 | 1205 | free_tsk: |
61c4628b SS |
1206 | free_task_struct(tsk); |
1207 | return NULL; | |
1da177e4 LT |
1208 | } |
1209 | ||
23ff4440 | 1210 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 1211 | |
4cb0e11b HK |
1212 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
1213 | ||
1214 | static int __init coredump_filter_setup(char *s) | |
1215 | { | |
1216 | default_dump_filter = | |
1217 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
1218 | MMF_DUMP_FILTER_MASK; | |
1219 | return 1; | |
1220 | } | |
1221 | ||
1222 | __setup("coredump_filter=", coredump_filter_setup); | |
1223 | ||
1da177e4 LT |
1224 | #include <linux/init_task.h> |
1225 | ||
858f0993 AD |
1226 | static void mm_init_aio(struct mm_struct *mm) |
1227 | { | |
1228 | #ifdef CONFIG_AIO | |
1229 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 1230 | mm->ioctx_table = NULL; |
858f0993 AD |
1231 | #endif |
1232 | } | |
1233 | ||
c3f3ce04 AA |
1234 | static __always_inline void mm_clear_owner(struct mm_struct *mm, |
1235 | struct task_struct *p) | |
1236 | { | |
1237 | #ifdef CONFIG_MEMCG | |
1238 | if (mm->owner == p) | |
1239 | WRITE_ONCE(mm->owner, NULL); | |
1240 | #endif | |
1241 | } | |
1242 | ||
33144e84 VD |
1243 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
1244 | { | |
1245 | #ifdef CONFIG_MEMCG | |
1246 | mm->owner = p; | |
1247 | #endif | |
1248 | } | |
1249 | ||
355627f5 EB |
1250 | static void mm_init_uprobes_state(struct mm_struct *mm) |
1251 | { | |
1252 | #ifdef CONFIG_UPROBES | |
1253 | mm->uprobes_state.xol_area = NULL; | |
1254 | #endif | |
1255 | } | |
1256 | ||
bfedb589 EB |
1257 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
1258 | struct user_namespace *user_ns) | |
1da177e4 | 1259 | { |
d4af56c5 LH |
1260 | mt_init_flags(&mm->mm_mt, MM_MT_FLAGS); |
1261 | mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock); | |
1da177e4 LT |
1262 | atomic_set(&mm->mm_users, 1); |
1263 | atomic_set(&mm->mm_count, 1); | |
57efa1fe | 1264 | seqcount_init(&mm->write_protect_seq); |
d8ed45c5 | 1265 | mmap_init_lock(mm); |
1da177e4 | 1266 | INIT_LIST_HEAD(&mm->mmlist); |
5e31275c SB |
1267 | #ifdef CONFIG_PER_VMA_LOCK |
1268 | mm->mm_lock_seq = 0; | |
1269 | #endif | |
af5b0f6a | 1270 | mm_pgtables_bytes_init(mm); |
41f727fd VD |
1271 | mm->map_count = 0; |
1272 | mm->locked_vm = 0; | |
70f8a3ca | 1273 | atomic64_set(&mm->pinned_vm, 0); |
d559db08 | 1274 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 1275 | spin_lock_init(&mm->page_table_lock); |
88aa7cc6 | 1276 | spin_lock_init(&mm->arg_lock); |
41f727fd | 1277 | mm_init_cpumask(mm); |
858f0993 | 1278 | mm_init_aio(mm); |
cf475ad2 | 1279 | mm_init_owner(mm, p); |
a6cbd440 | 1280 | mm_pasid_init(mm); |
2b7e8665 | 1281 | RCU_INIT_POINTER(mm->exe_file, NULL); |
984cfe4e | 1282 | mmu_notifier_subscriptions_init(mm); |
16af97dc | 1283 | init_tlb_flush_pending(mm); |
41f727fd VD |
1284 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
1285 | mm->pmd_huge_pte = NULL; | |
1286 | #endif | |
355627f5 | 1287 | mm_init_uprobes_state(mm); |
13db8c50 | 1288 | hugetlb_count_init(mm); |
1da177e4 | 1289 | |
a0715cc2 | 1290 | if (current->mm) { |
24e41bf8 | 1291 | mm->flags = mmf_init_flags(current->mm->flags); |
a0715cc2 AT |
1292 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; |
1293 | } else { | |
1294 | mm->flags = default_dump_filter; | |
1da177e4 | 1295 | mm->def_flags = 0; |
a0715cc2 AT |
1296 | } |
1297 | ||
41f727fd VD |
1298 | if (mm_alloc_pgd(mm)) |
1299 | goto fail_nopgd; | |
1300 | ||
1301 | if (init_new_context(p, mm)) | |
1302 | goto fail_nocontext; | |
78fb7466 | 1303 | |
223baf9d MD |
1304 | if (mm_alloc_cid(mm)) |
1305 | goto fail_cid; | |
1306 | ||
14ef95be MG |
1307 | if (percpu_counter_init_many(mm->rss_stat, 0, GFP_KERNEL_ACCOUNT, |
1308 | NR_MM_COUNTERS)) | |
1309 | goto fail_pcpu; | |
f1a79412 | 1310 | |
bfedb589 | 1311 | mm->user_ns = get_user_ns(user_ns); |
bd74fdae | 1312 | lru_gen_init_mm(mm); |
41f727fd VD |
1313 | return mm; |
1314 | ||
f1a79412 | 1315 | fail_pcpu: |
223baf9d MD |
1316 | mm_destroy_cid(mm); |
1317 | fail_cid: | |
b20b0368 | 1318 | destroy_context(mm); |
41f727fd VD |
1319 | fail_nocontext: |
1320 | mm_free_pgd(mm); | |
1321 | fail_nopgd: | |
1da177e4 LT |
1322 | free_mm(mm); |
1323 | return NULL; | |
1324 | } | |
1325 | ||
1326 | /* | |
1327 | * Allocate and initialize an mm_struct. | |
1328 | */ | |
fb0a685c | 1329 | struct mm_struct *mm_alloc(void) |
1da177e4 | 1330 | { |
fb0a685c | 1331 | struct mm_struct *mm; |
1da177e4 LT |
1332 | |
1333 | mm = allocate_mm(); | |
de03c72c KM |
1334 | if (!mm) |
1335 | return NULL; | |
1336 | ||
1337 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 1338 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
1339 | } |
1340 | ||
ec8d7c14 MH |
1341 | static inline void __mmput(struct mm_struct *mm) |
1342 | { | |
1343 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
1344 | ||
1345 | uprobe_clear_state(mm); | |
1346 | exit_aio(mm); | |
1347 | ksm_exit(mm); | |
1348 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
1349 | exit_mmap(mm); | |
6fcb52a5 | 1350 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
1351 | set_mm_exe_file(mm, NULL); |
1352 | if (!list_empty(&mm->mmlist)) { | |
1353 | spin_lock(&mmlist_lock); | |
1354 | list_del(&mm->mmlist); | |
1355 | spin_unlock(&mmlist_lock); | |
1356 | } | |
1357 | if (mm->binfmt) | |
1358 | module_put(mm->binfmt->module); | |
bd74fdae | 1359 | lru_gen_del_mm(mm); |
ec8d7c14 MH |
1360 | mmdrop(mm); |
1361 | } | |
1362 | ||
1da177e4 LT |
1363 | /* |
1364 | * Decrement the use count and release all resources for an mm. | |
1365 | */ | |
1366 | void mmput(struct mm_struct *mm) | |
1367 | { | |
0ae26f1b AM |
1368 | might_sleep(); |
1369 | ||
ec8d7c14 MH |
1370 | if (atomic_dec_and_test(&mm->mm_users)) |
1371 | __mmput(mm); | |
1372 | } | |
1373 | EXPORT_SYMBOL_GPL(mmput); | |
1374 | ||
a1b2289c SY |
1375 | #ifdef CONFIG_MMU |
1376 | static void mmput_async_fn(struct work_struct *work) | |
1377 | { | |
1378 | struct mm_struct *mm = container_of(work, struct mm_struct, | |
1379 | async_put_work); | |
1380 | ||
1381 | __mmput(mm); | |
1382 | } | |
1383 | ||
1384 | void mmput_async(struct mm_struct *mm) | |
1385 | { | |
1386 | if (atomic_dec_and_test(&mm->mm_users)) { | |
1387 | INIT_WORK(&mm->async_put_work, mmput_async_fn); | |
1388 | schedule_work(&mm->async_put_work); | |
1389 | } | |
1390 | } | |
85eaeb50 | 1391 | EXPORT_SYMBOL_GPL(mmput_async); |
a1b2289c SY |
1392 | #endif |
1393 | ||
90f31d0e KK |
1394 | /** |
1395 | * set_mm_exe_file - change a reference to the mm's executable file | |
ff0712ea MWO |
1396 | * @mm: The mm to change. |
1397 | * @new_exe_file: The new file to use. | |
90f31d0e KK |
1398 | * |
1399 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
1400 | * | |
6e399cd1 | 1401 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
a7031f14 MG |
1402 | * invocations: in mmput() nobody alive left, in execve it happens before |
1403 | * the new mm is made visible to anyone. | |
fe69d560 DH |
1404 | * |
1405 | * Can only fail if new_exe_file != NULL. | |
90f31d0e | 1406 | */ |
fe69d560 | 1407 | int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
38646013 | 1408 | { |
6e399cd1 DB |
1409 | struct file *old_exe_file; |
1410 | ||
1411 | /* | |
1412 | * It is safe to dereference the exe_file without RCU as | |
1413 | * this function is only called if nobody else can access | |
1414 | * this mm -- see comment above for justification. | |
1415 | */ | |
1416 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 1417 | |
fe69d560 DH |
1418 | if (new_exe_file) { |
1419 | /* | |
1420 | * We expect the caller (i.e., sys_execve) to already denied | |
1421 | * write access, so this is unlikely to fail. | |
1422 | */ | |
1423 | if (unlikely(deny_write_access(new_exe_file))) | |
1424 | return -EACCES; | |
38646013 | 1425 | get_file(new_exe_file); |
fe69d560 | 1426 | } |
90f31d0e | 1427 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
fe69d560 DH |
1428 | if (old_exe_file) { |
1429 | allow_write_access(old_exe_file); | |
90f31d0e | 1430 | fput(old_exe_file); |
fe69d560 DH |
1431 | } |
1432 | return 0; | |
38646013 JS |
1433 | } |
1434 | ||
35d7bdc8 DH |
1435 | /** |
1436 | * replace_mm_exe_file - replace a reference to the mm's executable file | |
ff0712ea MWO |
1437 | * @mm: The mm to change. |
1438 | * @new_exe_file: The new file to use. | |
35d7bdc8 | 1439 | * |
a7031f14 | 1440 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). |
35d7bdc8 DH |
1441 | * |
1442 | * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE). | |
1443 | */ | |
1444 | int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) | |
1445 | { | |
1446 | struct vm_area_struct *vma; | |
1447 | struct file *old_exe_file; | |
1448 | int ret = 0; | |
1449 | ||
1450 | /* Forbid mm->exe_file change if old file still mapped. */ | |
1451 | old_exe_file = get_mm_exe_file(mm); | |
1452 | if (old_exe_file) { | |
fa5e5876 | 1453 | VMA_ITERATOR(vmi, mm, 0); |
35d7bdc8 | 1454 | mmap_read_lock(mm); |
fa5e5876 | 1455 | for_each_vma(vmi, vma) { |
35d7bdc8 DH |
1456 | if (!vma->vm_file) |
1457 | continue; | |
1458 | if (path_equal(&vma->vm_file->f_path, | |
fa5e5876 | 1459 | &old_exe_file->f_path)) { |
35d7bdc8 | 1460 | ret = -EBUSY; |
fa5e5876 MWO |
1461 | break; |
1462 | } | |
35d7bdc8 DH |
1463 | } |
1464 | mmap_read_unlock(mm); | |
1465 | fput(old_exe_file); | |
1466 | if (ret) | |
1467 | return ret; | |
1468 | } | |
1469 | ||
fe69d560 DH |
1470 | ret = deny_write_access(new_exe_file); |
1471 | if (ret) | |
1472 | return -EACCES; | |
35d7bdc8 | 1473 | get_file(new_exe_file); |
fe69d560 | 1474 | |
a7031f14 MG |
1475 | /* set the new file */ |
1476 | mmap_write_lock(mm); | |
1477 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
1478 | rcu_assign_pointer(mm->exe_file, new_exe_file); | |
1479 | mmap_write_unlock(mm); | |
1480 | ||
fe69d560 | 1481 | if (old_exe_file) { |
fe69d560 | 1482 | allow_write_access(old_exe_file); |
35d7bdc8 | 1483 | fput(old_exe_file); |
fe69d560 | 1484 | } |
35d7bdc8 | 1485 | return 0; |
38646013 JS |
1486 | } |
1487 | ||
90f31d0e KK |
1488 | /** |
1489 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
ff0712ea | 1490 | * @mm: The mm of interest. |
90f31d0e KK |
1491 | * |
1492 | * Returns %NULL if mm has no associated executable file. | |
1493 | * User must release file via fput(). | |
1494 | */ | |
38646013 JS |
1495 | struct file *get_mm_exe_file(struct mm_struct *mm) |
1496 | { | |
1497 | struct file *exe_file; | |
1498 | ||
90f31d0e | 1499 | rcu_read_lock(); |
0ede61d8 | 1500 | exe_file = get_file_rcu(&mm->exe_file); |
90f31d0e | 1501 | rcu_read_unlock(); |
38646013 JS |
1502 | return exe_file; |
1503 | } | |
1504 | ||
cd81a917 MG |
1505 | /** |
1506 | * get_task_exe_file - acquire a reference to the task's executable file | |
ff0712ea | 1507 | * @task: The task. |
cd81a917 MG |
1508 | * |
1509 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
1510 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
1511 | * User must release file via fput(). | |
1512 | */ | |
1513 | struct file *get_task_exe_file(struct task_struct *task) | |
1514 | { | |
1515 | struct file *exe_file = NULL; | |
1516 | struct mm_struct *mm; | |
1517 | ||
1518 | task_lock(task); | |
1519 | mm = task->mm; | |
1520 | if (mm) { | |
1521 | if (!(task->flags & PF_KTHREAD)) | |
1522 | exe_file = get_mm_exe_file(mm); | |
1523 | } | |
1524 | task_unlock(task); | |
1525 | return exe_file; | |
1526 | } | |
38646013 | 1527 | |
1da177e4 LT |
1528 | /** |
1529 | * get_task_mm - acquire a reference to the task's mm | |
ff0712ea | 1530 | * @task: The task. |
1da177e4 | 1531 | * |
246bb0b1 | 1532 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
1533 | * this kernel workthread has transiently adopted a user mm with use_mm, |
1534 | * to do its AIO) is not set and if so returns a reference to it, after | |
1535 | * bumping up the use count. User must release the mm via mmput() | |
1536 | * after use. Typically used by /proc and ptrace. | |
1537 | */ | |
1538 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1539 | { | |
1540 | struct mm_struct *mm; | |
1541 | ||
1542 | task_lock(task); | |
1543 | mm = task->mm; | |
1544 | if (mm) { | |
246bb0b1 | 1545 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1546 | mm = NULL; |
1547 | else | |
3fce371b | 1548 | mmget(mm); |
1da177e4 LT |
1549 | } |
1550 | task_unlock(task); | |
1551 | return mm; | |
1552 | } | |
1553 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1554 | ||
8cdb878d CY |
1555 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1556 | { | |
1557 | struct mm_struct *mm; | |
1558 | int err; | |
1559 | ||
f7cfd871 | 1560 | err = down_read_killable(&task->signal->exec_update_lock); |
8cdb878d CY |
1561 | if (err) |
1562 | return ERR_PTR(err); | |
1563 | ||
1564 | mm = get_task_mm(task); | |
1565 | if (mm && mm != current->mm && | |
1566 | !ptrace_may_access(task, mode)) { | |
1567 | mmput(mm); | |
1568 | mm = ERR_PTR(-EACCES); | |
1569 | } | |
f7cfd871 | 1570 | up_read(&task->signal->exec_update_lock); |
8cdb878d CY |
1571 | |
1572 | return mm; | |
1573 | } | |
1574 | ||
57b59c4a | 1575 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1576 | { |
d68b46fe | 1577 | struct completion *vfork; |
c415c3b4 | 1578 | |
d68b46fe ON |
1579 | task_lock(tsk); |
1580 | vfork = tsk->vfork_done; | |
1581 | if (likely(vfork)) { | |
1582 | tsk->vfork_done = NULL; | |
1583 | complete(vfork); | |
1584 | } | |
1585 | task_unlock(tsk); | |
1586 | } | |
1587 | ||
1588 | static int wait_for_vfork_done(struct task_struct *child, | |
1589 | struct completion *vfork) | |
1590 | { | |
f5d39b02 | 1591 | unsigned int state = TASK_UNINTERRUPTIBLE|TASK_KILLABLE|TASK_FREEZABLE; |
d68b46fe ON |
1592 | int killed; |
1593 | ||
76f969e8 | 1594 | cgroup_enter_frozen(); |
f5d39b02 | 1595 | killed = wait_for_completion_state(vfork, state); |
76f969e8 | 1596 | cgroup_leave_frozen(false); |
d68b46fe ON |
1597 | |
1598 | if (killed) { | |
1599 | task_lock(child); | |
1600 | child->vfork_done = NULL; | |
1601 | task_unlock(child); | |
1602 | } | |
1603 | ||
1604 | put_task_struct(child); | |
1605 | return killed; | |
c415c3b4 ON |
1606 | } |
1607 | ||
1da177e4 LT |
1608 | /* Please note the differences between mmput and mm_release. |
1609 | * mmput is called whenever we stop holding onto a mm_struct, | |
1610 | * error success whatever. | |
1611 | * | |
1612 | * mm_release is called after a mm_struct has been removed | |
1613 | * from the current process. | |
1614 | * | |
1615 | * This difference is important for error handling, when we | |
1616 | * only half set up a mm_struct for a new process and need to restore | |
1617 | * the old one. Because we mmput the new mm_struct before | |
1618 | * restoring the old one. . . | |
1619 | * Eric Biederman 10 January 1998 | |
1620 | */ | |
4610ba7a | 1621 | static void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1da177e4 | 1622 | { |
0326f5a9 SD |
1623 | uprobe_free_utask(tsk); |
1624 | ||
1da177e4 LT |
1625 | /* Get rid of any cached register state */ |
1626 | deactivate_mm(tsk, mm); | |
1627 | ||
fec1d011 | 1628 | /* |
735f2770 MH |
1629 | * Signal userspace if we're not exiting with a core dump |
1630 | * because we want to leave the value intact for debugging | |
1631 | * purposes. | |
fec1d011 | 1632 | */ |
9c8a8228 | 1633 | if (tsk->clear_child_tid) { |
92307383 | 1634 | if (atomic_read(&mm->mm_users) > 1) { |
9c8a8228 ED |
1635 | /* |
1636 | * We don't check the error code - if userspace has | |
1637 | * not set up a proper pointer then tough luck. | |
1638 | */ | |
1639 | put_user(0, tsk->clear_child_tid); | |
2de0db99 DB |
1640 | do_futex(tsk->clear_child_tid, FUTEX_WAKE, |
1641 | 1, NULL, NULL, 0, 0); | |
9c8a8228 | 1642 | } |
1da177e4 | 1643 | tsk->clear_child_tid = NULL; |
1da177e4 | 1644 | } |
f7505d64 KK |
1645 | |
1646 | /* | |
1647 | * All done, finally we can wake up parent and return this mm to him. | |
1648 | * Also kthread_stop() uses this completion for synchronization. | |
1649 | */ | |
1650 | if (tsk->vfork_done) | |
1651 | complete_vfork_done(tsk); | |
1da177e4 LT |
1652 | } |
1653 | ||
4610ba7a TG |
1654 | void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1655 | { | |
150d7158 | 1656 | futex_exit_release(tsk); |
4610ba7a TG |
1657 | mm_release(tsk, mm); |
1658 | } | |
1659 | ||
1660 | void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1661 | { | |
150d7158 | 1662 | futex_exec_release(tsk); |
4610ba7a TG |
1663 | mm_release(tsk, mm); |
1664 | } | |
1665 | ||
13585fa0 NA |
1666 | /** |
1667 | * dup_mm() - duplicates an existing mm structure | |
1668 | * @tsk: the task_struct with which the new mm will be associated. | |
1669 | * @oldmm: the mm to duplicate. | |
1670 | * | |
1671 | * Allocates a new mm structure and duplicates the provided @oldmm structure | |
1672 | * content into it. | |
1673 | * | |
1674 | * Return: the duplicated mm or NULL on failure. | |
a0a7ec30 | 1675 | */ |
13585fa0 NA |
1676 | static struct mm_struct *dup_mm(struct task_struct *tsk, |
1677 | struct mm_struct *oldmm) | |
a0a7ec30 | 1678 | { |
13585fa0 | 1679 | struct mm_struct *mm; |
a0a7ec30 JD |
1680 | int err; |
1681 | ||
a0a7ec30 JD |
1682 | mm = allocate_mm(); |
1683 | if (!mm) | |
1684 | goto fail_nomem; | |
1685 | ||
1686 | memcpy(mm, oldmm, sizeof(*mm)); | |
1687 | ||
bfedb589 | 1688 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1689 | goto fail_nomem; |
1690 | ||
a0a7ec30 JD |
1691 | err = dup_mmap(mm, oldmm); |
1692 | if (err) | |
1693 | goto free_pt; | |
1694 | ||
1695 | mm->hiwater_rss = get_mm_rss(mm); | |
1696 | mm->hiwater_vm = mm->total_vm; | |
1697 | ||
801460d0 HS |
1698 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1699 | goto free_pt; | |
1700 | ||
a0a7ec30 JD |
1701 | return mm; |
1702 | ||
1703 | free_pt: | |
801460d0 HS |
1704 | /* don't put binfmt in mmput, we haven't got module yet */ |
1705 | mm->binfmt = NULL; | |
c3f3ce04 | 1706 | mm_init_owner(mm, NULL); |
a0a7ec30 JD |
1707 | mmput(mm); |
1708 | ||
1709 | fail_nomem: | |
1710 | return NULL; | |
a0a7ec30 JD |
1711 | } |
1712 | ||
fb0a685c | 1713 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1714 | { |
fb0a685c | 1715 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1716 | |
1717 | tsk->min_flt = tsk->maj_flt = 0; | |
1718 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1719 | #ifdef CONFIG_DETECT_HUNG_TASK |
1720 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
a2e51445 | 1721 | tsk->last_switch_time = 0; |
17406b82 | 1722 | #endif |
1da177e4 LT |
1723 | |
1724 | tsk->mm = NULL; | |
1725 | tsk->active_mm = NULL; | |
1726 | ||
1727 | /* | |
1728 | * Are we cloning a kernel thread? | |
1729 | * | |
1730 | * We need to steal a active VM for that.. | |
1731 | */ | |
1732 | oldmm = current->mm; | |
1733 | if (!oldmm) | |
1734 | return 0; | |
1735 | ||
1736 | if (clone_flags & CLONE_VM) { | |
3fce371b | 1737 | mmget(oldmm); |
1da177e4 | 1738 | mm = oldmm; |
a6895399 REB |
1739 | } else { |
1740 | mm = dup_mm(tsk, current->mm); | |
1741 | if (!mm) | |
1742 | return -ENOMEM; | |
1da177e4 LT |
1743 | } |
1744 | ||
1da177e4 LT |
1745 | tsk->mm = mm; |
1746 | tsk->active_mm = mm; | |
af7f588d | 1747 | sched_mm_cid_fork(tsk); |
1da177e4 | 1748 | return 0; |
1da177e4 LT |
1749 | } |
1750 | ||
a39bc516 | 1751 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1752 | { |
498052bb | 1753 | struct fs_struct *fs = current->fs; |
1da177e4 | 1754 | if (clone_flags & CLONE_FS) { |
498052bb | 1755 | /* tsk->fs is already what we want */ |
2a4419b5 | 1756 | spin_lock(&fs->lock); |
498052bb | 1757 | if (fs->in_exec) { |
2a4419b5 | 1758 | spin_unlock(&fs->lock); |
498052bb AV |
1759 | return -EAGAIN; |
1760 | } | |
1761 | fs->users++; | |
2a4419b5 | 1762 | spin_unlock(&fs->lock); |
1da177e4 LT |
1763 | return 0; |
1764 | } | |
498052bb | 1765 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1766 | if (!tsk->fs) |
1767 | return -ENOMEM; | |
1768 | return 0; | |
1769 | } | |
1770 | ||
11f3f500 MC |
1771 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk, |
1772 | int no_files) | |
a016f338 JD |
1773 | { |
1774 | struct files_struct *oldf, *newf; | |
1775 | int error = 0; | |
1776 | ||
1777 | /* | |
1778 | * A background process may not have any files ... | |
1779 | */ | |
1780 | oldf = current->files; | |
1781 | if (!oldf) | |
1782 | goto out; | |
1783 | ||
11f3f500 MC |
1784 | if (no_files) { |
1785 | tsk->files = NULL; | |
1786 | goto out; | |
1787 | } | |
1788 | ||
a016f338 JD |
1789 | if (clone_flags & CLONE_FILES) { |
1790 | atomic_inc(&oldf->count); | |
1791 | goto out; | |
1792 | } | |
1793 | ||
60997c3d | 1794 | newf = dup_fd(oldf, NR_OPEN_MAX, &error); |
a016f338 JD |
1795 | if (!newf) |
1796 | goto out; | |
1797 | ||
1798 | tsk->files = newf; | |
1799 | error = 0; | |
1800 | out: | |
1801 | return error; | |
1802 | } | |
1803 | ||
a39bc516 | 1804 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1805 | { |
1806 | struct sighand_struct *sig; | |
1807 | ||
60348802 | 1808 | if (clone_flags & CLONE_SIGHAND) { |
d036bda7 | 1809 | refcount_inc(¤t->sighand->count); |
1da177e4 LT |
1810 | return 0; |
1811 | } | |
1812 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
0c282b06 | 1813 | RCU_INIT_POINTER(tsk->sighand, sig); |
1da177e4 LT |
1814 | if (!sig) |
1815 | return -ENOMEM; | |
9d7fb042 | 1816 | |
d036bda7 | 1817 | refcount_set(&sig->count, 1); |
06e62a46 | 1818 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1819 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
06e62a46 | 1820 | spin_unlock_irq(¤t->sighand->siglock); |
b612e5df CB |
1821 | |
1822 | /* Reset all signal handler not set to SIG_IGN to SIG_DFL. */ | |
1823 | if (clone_flags & CLONE_CLEAR_SIGHAND) | |
1824 | flush_signal_handlers(tsk, 0); | |
1825 | ||
1da177e4 LT |
1826 | return 0; |
1827 | } | |
1828 | ||
a7e5328a | 1829 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1830 | { |
d036bda7 | 1831 | if (refcount_dec_and_test(&sighand->count)) { |
d80e731e | 1832 | signalfd_cleanup(sighand); |
392809b2 | 1833 | /* |
5f0d5a3a | 1834 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it |
392809b2 ON |
1835 | * without an RCU grace period, see __lock_task_sighand(). |
1836 | */ | |
c81addc9 | 1837 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1838 | } |
c81addc9 ON |
1839 | } |
1840 | ||
f06febc9 FM |
1841 | /* |
1842 | * Initialize POSIX timer handling for a thread group. | |
1843 | */ | |
1844 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1845 | { | |
2b69942f | 1846 | struct posix_cputimers *pct = &sig->posix_cputimers; |
78d7d407 JS |
1847 | unsigned long cpu_limit; |
1848 | ||
316c1608 | 1849 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
3a245c0f | 1850 | posix_cputimers_group_init(pct, cpu_limit); |
f06febc9 FM |
1851 | } |
1852 | ||
a39bc516 | 1853 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1854 | { |
1855 | struct signal_struct *sig; | |
1da177e4 | 1856 | |
4ab6c083 | 1857 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1858 | return 0; |
490dea45 | 1859 | |
a56704ef | 1860 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1861 | tsk->signal = sig; |
1862 | if (!sig) | |
1863 | return -ENOMEM; | |
1864 | ||
b3ac022c | 1865 | sig->nr_threads = 1; |
d80f7d7b | 1866 | sig->quick_threads = 1; |
1da177e4 | 1867 | atomic_set(&sig->live, 1); |
60d4de3f | 1868 | refcount_set(&sig->sigcnt, 1); |
0c740d0a ON |
1869 | |
1870 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1871 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1872 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1873 | ||
1da177e4 | 1874 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1875 | sig->curr_target = tsk; |
1da177e4 | 1876 | init_sigpending(&sig->shared_pending); |
c3ad2c3b | 1877 | INIT_HLIST_HEAD(&sig->multiprocess); |
e78c3496 | 1878 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1879 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1880 | |
baa73d9e | 1881 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1882 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1883 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1884 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1885 | #endif |
1da177e4 | 1886 | |
1da177e4 LT |
1887 | task_lock(current->group_leader); |
1888 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1889 | task_unlock(current->group_leader); | |
1890 | ||
6279a751 ON |
1891 | posix_cpu_timers_init_group(sig); |
1892 | ||
522ed776 | 1893 | tty_audit_fork(sig); |
5091faa4 | 1894 | sched_autogroup_fork(sig); |
522ed776 | 1895 | |
a63d83f4 | 1896 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1897 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1898 | |
9b1bf12d | 1899 | mutex_init(&sig->cred_guard_mutex); |
f7cfd871 | 1900 | init_rwsem(&sig->exec_update_lock); |
9b1bf12d | 1901 | |
1da177e4 LT |
1902 | return 0; |
1903 | } | |
1904 | ||
dbd95212 KC |
1905 | static void copy_seccomp(struct task_struct *p) |
1906 | { | |
1907 | #ifdef CONFIG_SECCOMP | |
1908 | /* | |
1909 | * Must be called with sighand->lock held, which is common to | |
1910 | * all threads in the group. Holding cred_guard_mutex is not | |
1911 | * needed because this new task is not yet running and cannot | |
1912 | * be racing exec. | |
1913 | */ | |
69f6a34b | 1914 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1915 | |
1916 | /* Ref-count the new filter user, and assign it. */ | |
1917 | get_seccomp_filter(current); | |
1918 | p->seccomp = current->seccomp; | |
1919 | ||
1920 | /* | |
1921 | * Explicitly enable no_new_privs here in case it got set | |
1922 | * between the task_struct being duplicated and holding the | |
1923 | * sighand lock. The seccomp state and nnp must be in sync. | |
1924 | */ | |
1925 | if (task_no_new_privs(current)) | |
1926 | task_set_no_new_privs(p); | |
1927 | ||
1928 | /* | |
1929 | * If the parent gained a seccomp mode after copying thread | |
1930 | * flags and between before we held the sighand lock, we have | |
1931 | * to manually enable the seccomp thread flag here. | |
1932 | */ | |
1933 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
23d67a54 | 1934 | set_task_syscall_work(p, SECCOMP); |
dbd95212 KC |
1935 | #endif |
1936 | } | |
1937 | ||
17da2bd9 | 1938 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1939 | { |
1940 | current->clear_child_tid = tidptr; | |
1941 | ||
b488893a | 1942 | return task_pid_vnr(current); |
1da177e4 LT |
1943 | } |
1944 | ||
a39bc516 | 1945 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1946 | { |
1d615482 | 1947 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1948 | #ifdef CONFIG_RT_MUTEXES |
a23ba907 | 1949 | p->pi_waiters = RB_ROOT_CACHED; |
e96a7705 | 1950 | p->pi_top_task = NULL; |
23f78d4a | 1951 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1952 | #endif |
1953 | } | |
1954 | ||
2c470475 EB |
1955 | static inline void init_task_pid_links(struct task_struct *task) |
1956 | { | |
1957 | enum pid_type type; | |
1958 | ||
96e1e984 | 1959 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) |
2c470475 | 1960 | INIT_HLIST_NODE(&task->pid_links[type]); |
2c470475 EB |
1961 | } |
1962 | ||
81907739 ON |
1963 | static inline void |
1964 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1965 | { | |
2c470475 EB |
1966 | if (type == PIDTYPE_PID) |
1967 | task->thread_pid = pid; | |
1968 | else | |
1969 | task->signal->pids[type] = pid; | |
81907739 ON |
1970 | } |
1971 | ||
6bfbaa51 IM |
1972 | static inline void rcu_copy_process(struct task_struct *p) |
1973 | { | |
1974 | #ifdef CONFIG_PREEMPT_RCU | |
1975 | p->rcu_read_lock_nesting = 0; | |
1976 | p->rcu_read_unlock_special.s = 0; | |
1977 | p->rcu_blocked_node = NULL; | |
1978 | INIT_LIST_HEAD(&p->rcu_node_entry); | |
1979 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1980 | #ifdef CONFIG_TASKS_RCU | |
1981 | p->rcu_tasks_holdout = false; | |
1982 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); | |
1983 | p->rcu_tasks_idle_cpu = -1; | |
1984 | #endif /* #ifdef CONFIG_TASKS_RCU */ | |
d5f177d3 PM |
1985 | #ifdef CONFIG_TASKS_TRACE_RCU |
1986 | p->trc_reader_nesting = 0; | |
276c4104 | 1987 | p->trc_reader_special.s = 0; |
d5f177d3 | 1988 | INIT_LIST_HEAD(&p->trc_holdout_list); |
434c9eef | 1989 | INIT_LIST_HEAD(&p->trc_blkd_node); |
d5f177d3 | 1990 | #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ |
6bfbaa51 IM |
1991 | } |
1992 | ||
3695eae5 CB |
1993 | struct pid *pidfd_pid(const struct file *file) |
1994 | { | |
1995 | if (file->f_op == &pidfd_fops) | |
1996 | return file->private_data; | |
1997 | ||
1998 | return ERR_PTR(-EBADF); | |
1999 | } | |
2000 | ||
b3e58382 CB |
2001 | static int pidfd_release(struct inode *inode, struct file *file) |
2002 | { | |
2003 | struct pid *pid = file->private_data; | |
2004 | ||
2005 | file->private_data = NULL; | |
2006 | put_pid(pid); | |
2007 | return 0; | |
2008 | } | |
2009 | ||
2010 | #ifdef CONFIG_PROC_FS | |
15d42eb2 CK |
2011 | /** |
2012 | * pidfd_show_fdinfo - print information about a pidfd | |
2013 | * @m: proc fdinfo file | |
2014 | * @f: file referencing a pidfd | |
2015 | * | |
2016 | * Pid: | |
2017 | * This function will print the pid that a given pidfd refers to in the | |
2018 | * pid namespace of the procfs instance. | |
2019 | * If the pid namespace of the process is not a descendant of the pid | |
2020 | * namespace of the procfs instance 0 will be shown as its pid. This is | |
2021 | * similar to calling getppid() on a process whose parent is outside of | |
2022 | * its pid namespace. | |
2023 | * | |
2024 | * NSpid: | |
2025 | * If pid namespaces are supported then this function will also print | |
2026 | * the pid of a given pidfd refers to for all descendant pid namespaces | |
2027 | * starting from the current pid namespace of the instance, i.e. the | |
2028 | * Pid field and the first entry in the NSpid field will be identical. | |
2029 | * If the pid namespace of the process is not a descendant of the pid | |
2030 | * namespace of the procfs instance 0 will be shown as its first NSpid | |
2031 | * entry and no others will be shown. | |
2032 | * Note that this differs from the Pid and NSpid fields in | |
2033 | * /proc/<pid>/status where Pid and NSpid are always shown relative to | |
2034 | * the pid namespace of the procfs instance. The difference becomes | |
2035 | * obvious when sending around a pidfd between pid namespaces from a | |
a8ca6b13 | 2036 | * different branch of the tree, i.e. where no ancestral relation is |
15d42eb2 CK |
2037 | * present between the pid namespaces: |
2038 | * - create two new pid namespaces ns1 and ns2 in the initial pid | |
2039 | * namespace (also take care to create new mount namespaces in the | |
2040 | * new pid namespace and mount procfs) | |
2041 | * - create a process with a pidfd in ns1 | |
2042 | * - send pidfd from ns1 to ns2 | |
2043 | * - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid | |
2044 | * have exactly one entry, which is 0 | |
2045 | */ | |
b3e58382 CB |
2046 | static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) |
2047 | { | |
b3e58382 | 2048 | struct pid *pid = f->private_data; |
3d6d8da4 CB |
2049 | struct pid_namespace *ns; |
2050 | pid_t nr = -1; | |
15d42eb2 | 2051 | |
3d6d8da4 | 2052 | if (likely(pid_has_task(pid, PIDTYPE_PID))) { |
9d78edea | 2053 | ns = proc_pid_ns(file_inode(m->file)->i_sb); |
3d6d8da4 CB |
2054 | nr = pid_nr_ns(pid, ns); |
2055 | } | |
2056 | ||
2057 | seq_put_decimal_ll(m, "Pid:\t", nr); | |
b3e58382 | 2058 | |
15d42eb2 | 2059 | #ifdef CONFIG_PID_NS |
3d6d8da4 CB |
2060 | seq_put_decimal_ll(m, "\nNSpid:\t", nr); |
2061 | if (nr > 0) { | |
15d42eb2 | 2062 | int i; |
b3e58382 | 2063 | |
15d42eb2 CK |
2064 | /* If nr is non-zero it means that 'pid' is valid and that |
2065 | * ns, i.e. the pid namespace associated with the procfs | |
2066 | * instance, is in the pid namespace hierarchy of pid. | |
2067 | * Start at one below the already printed level. | |
2068 | */ | |
2069 | for (i = ns->level + 1; i <= pid->level; i++) | |
3d6d8da4 | 2070 | seq_put_decimal_ll(m, "\t", pid->numbers[i].nr); |
15d42eb2 CK |
2071 | } |
2072 | #endif | |
b3e58382 CB |
2073 | seq_putc(m, '\n'); |
2074 | } | |
2075 | #endif | |
2076 | ||
b53b0b9d JFG |
2077 | /* |
2078 | * Poll support for process exit notification. | |
2079 | */ | |
9e77716a | 2080 | static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) |
b53b0b9d | 2081 | { |
b53b0b9d | 2082 | struct pid *pid = file->private_data; |
9e77716a | 2083 | __poll_t poll_flags = 0; |
b53b0b9d JFG |
2084 | |
2085 | poll_wait(file, &pid->wait_pidfd, pts); | |
2086 | ||
b53b0b9d JFG |
2087 | /* |
2088 | * Inform pollers only when the whole thread group exits. | |
2089 | * If the thread group leader exits before all other threads in the | |
2090 | * group, then poll(2) should block, similar to the wait(2) family. | |
2091 | */ | |
38fd525a | 2092 | if (thread_group_exited(pid)) |
9e77716a | 2093 | poll_flags = EPOLLIN | EPOLLRDNORM; |
b53b0b9d JFG |
2094 | |
2095 | return poll_flags; | |
2096 | } | |
2097 | ||
b3e58382 CB |
2098 | const struct file_operations pidfd_fops = { |
2099 | .release = pidfd_release, | |
b53b0b9d | 2100 | .poll = pidfd_poll, |
b3e58382 CB |
2101 | #ifdef CONFIG_PROC_FS |
2102 | .show_fdinfo = pidfd_show_fdinfo, | |
2103 | #endif | |
2104 | }; | |
2105 | ||
6ae930d9 CB |
2106 | /** |
2107 | * __pidfd_prepare - allocate a new pidfd_file and reserve a pidfd | |
2108 | * @pid: the struct pid for which to create a pidfd | |
2109 | * @flags: flags of the new @pidfd | |
ff0712ea | 2110 | * @ret: Where to return the file for the pidfd. |
6ae930d9 CB |
2111 | * |
2112 | * Allocate a new file that stashes @pid and reserve a new pidfd number in the | |
2113 | * caller's file descriptor table. The pidfd is reserved but not installed yet. | |
ff0712ea | 2114 | * |
6ae930d9 CB |
2115 | * The helper doesn't perform checks on @pid which makes it useful for pidfds |
2116 | * created via CLONE_PIDFD where @pid has no task attached when the pidfd and | |
2117 | * pidfd file are prepared. | |
2118 | * | |
2119 | * If this function returns successfully the caller is responsible to either | |
2120 | * call fd_install() passing the returned pidfd and pidfd file as arguments in | |
2121 | * order to install the pidfd into its file descriptor table or they must use | |
2122 | * put_unused_fd() and fput() on the returned pidfd and pidfd file | |
2123 | * respectively. | |
2124 | * | |
2125 | * This function is useful when a pidfd must already be reserved but there | |
2126 | * might still be points of failure afterwards and the caller wants to ensure | |
2127 | * that no pidfd is leaked into its file descriptor table. | |
2128 | * | |
2129 | * Return: On success, a reserved pidfd is returned from the function and a new | |
2130 | * pidfd file is returned in the last argument to the function. On | |
2131 | * error, a negative error code is returned from the function and the | |
2132 | * last argument remains unchanged. | |
2133 | */ | |
2134 | static int __pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret) | |
2135 | { | |
2136 | int pidfd; | |
2137 | struct file *pidfd_file; | |
2138 | ||
2139 | if (flags & ~(O_NONBLOCK | O_RDWR | O_CLOEXEC)) | |
2140 | return -EINVAL; | |
2141 | ||
2142 | pidfd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); | |
2143 | if (pidfd < 0) | |
2144 | return pidfd; | |
2145 | ||
2146 | pidfd_file = anon_inode_getfile("[pidfd]", &pidfd_fops, pid, | |
2147 | flags | O_RDWR | O_CLOEXEC); | |
2148 | if (IS_ERR(pidfd_file)) { | |
2149 | put_unused_fd(pidfd); | |
2150 | return PTR_ERR(pidfd_file); | |
2151 | } | |
2152 | get_pid(pid); /* held by pidfd_file now */ | |
2153 | *ret = pidfd_file; | |
2154 | return pidfd; | |
2155 | } | |
2156 | ||
2157 | /** | |
2158 | * pidfd_prepare - allocate a new pidfd_file and reserve a pidfd | |
2159 | * @pid: the struct pid for which to create a pidfd | |
2160 | * @flags: flags of the new @pidfd | |
ff0712ea | 2161 | * @ret: Where to return the pidfd. |
6ae930d9 CB |
2162 | * |
2163 | * Allocate a new file that stashes @pid and reserve a new pidfd number in the | |
2164 | * caller's file descriptor table. The pidfd is reserved but not installed yet. | |
2165 | * | |
2166 | * The helper verifies that @pid is used as a thread group leader. | |
2167 | * | |
2168 | * If this function returns successfully the caller is responsible to either | |
2169 | * call fd_install() passing the returned pidfd and pidfd file as arguments in | |
2170 | * order to install the pidfd into its file descriptor table or they must use | |
2171 | * put_unused_fd() and fput() on the returned pidfd and pidfd file | |
2172 | * respectively. | |
2173 | * | |
2174 | * This function is useful when a pidfd must already be reserved but there | |
2175 | * might still be points of failure afterwards and the caller wants to ensure | |
2176 | * that no pidfd is leaked into its file descriptor table. | |
2177 | * | |
2178 | * Return: On success, a reserved pidfd is returned from the function and a new | |
2179 | * pidfd file is returned in the last argument to the function. On | |
2180 | * error, a negative error code is returned from the function and the | |
2181 | * last argument remains unchanged. | |
2182 | */ | |
2183 | int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret) | |
2184 | { | |
2185 | if (!pid || !pid_has_task(pid, PIDTYPE_TGID)) | |
2186 | return -EINVAL; | |
2187 | ||
2188 | return __pidfd_prepare(pid, flags, ret); | |
2189 | } | |
2190 | ||
c3f3ce04 AA |
2191 | static void __delayed_free_task(struct rcu_head *rhp) |
2192 | { | |
2193 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); | |
2194 | ||
2195 | free_task(tsk); | |
2196 | } | |
2197 | ||
2198 | static __always_inline void delayed_free_task(struct task_struct *tsk) | |
2199 | { | |
2200 | if (IS_ENABLED(CONFIG_MEMCG)) | |
2201 | call_rcu(&tsk->rcu, __delayed_free_task); | |
2202 | else | |
2203 | free_task(tsk); | |
2204 | } | |
2205 | ||
67197a4f SB |
2206 | static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk) |
2207 | { | |
2208 | /* Skip if kernel thread */ | |
2209 | if (!tsk->mm) | |
2210 | return; | |
2211 | ||
2212 | /* Skip if spawning a thread or using vfork */ | |
2213 | if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM) | |
2214 | return; | |
2215 | ||
2216 | /* We need to synchronize with __set_oom_adj */ | |
2217 | mutex_lock(&oom_adj_mutex); | |
2218 | set_bit(MMF_MULTIPROCESS, &tsk->mm->flags); | |
2219 | /* Update the values in case they were changed after copy_signal */ | |
2220 | tsk->signal->oom_score_adj = current->signal->oom_score_adj; | |
2221 | tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min; | |
2222 | mutex_unlock(&oom_adj_mutex); | |
2223 | } | |
2224 | ||
79257534 DBO |
2225 | #ifdef CONFIG_RV |
2226 | static void rv_task_fork(struct task_struct *p) | |
2227 | { | |
2228 | int i; | |
2229 | ||
2230 | for (i = 0; i < RV_PER_TASK_MONITORS; i++) | |
2231 | p->rv[i].da_mon.monitoring = false; | |
2232 | } | |
2233 | #else | |
2234 | #define rv_task_fork(p) do {} while (0) | |
2235 | #endif | |
2236 | ||
1da177e4 LT |
2237 | /* |
2238 | * This creates a new process as a copy of the old one, | |
2239 | * but does not actually start it yet. | |
2240 | * | |
2241 | * It copies the registers, and all the appropriate | |
2242 | * parts of the process environment (as per the clone | |
2243 | * flags). The actual kick-off is left to the caller. | |
2244 | */ | |
89c8e98d | 2245 | __latent_entropy struct task_struct *copy_process( |
09a05394 | 2246 | struct pid *pid, |
3033f14a | 2247 | int trace, |
7f192e3c CB |
2248 | int node, |
2249 | struct kernel_clone_args *args) | |
1da177e4 | 2250 | { |
b3e58382 | 2251 | int pidfd = -1, retval; |
a24efe62 | 2252 | struct task_struct *p; |
c3ad2c3b | 2253 | struct multiprocess_signals delayed; |
6fd2fe49 | 2254 | struct file *pidfile = NULL; |
c5febea0 | 2255 | const u64 clone_flags = args->flags; |
769071ac | 2256 | struct nsproxy *nsp = current->nsproxy; |
1da177e4 | 2257 | |
667b6094 MPS |
2258 | /* |
2259 | * Don't allow sharing the root directory with processes in a different | |
2260 | * namespace | |
2261 | */ | |
1da177e4 LT |
2262 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
2263 | return ERR_PTR(-EINVAL); | |
2264 | ||
e66eded8 EB |
2265 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
2266 | return ERR_PTR(-EINVAL); | |
2267 | ||
1da177e4 LT |
2268 | /* |
2269 | * Thread groups must share signals as well, and detached threads | |
2270 | * can only be started up within the thread group. | |
2271 | */ | |
2272 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
2273 | return ERR_PTR(-EINVAL); | |
2274 | ||
2275 | /* | |
2276 | * Shared signal handlers imply shared VM. By way of the above, | |
2277 | * thread groups also imply shared VM. Blocking this case allows | |
2278 | * for various simplifications in other code. | |
2279 | */ | |
2280 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
2281 | return ERR_PTR(-EINVAL); | |
2282 | ||
123be07b SB |
2283 | /* |
2284 | * Siblings of global init remain as zombies on exit since they are | |
2285 | * not reaped by their parent (swapper). To solve this and to avoid | |
2286 | * multi-rooted process trees, prevent global and container-inits | |
2287 | * from creating siblings. | |
2288 | */ | |
2289 | if ((clone_flags & CLONE_PARENT) && | |
2290 | current->signal->flags & SIGNAL_UNKILLABLE) | |
2291 | return ERR_PTR(-EINVAL); | |
2292 | ||
8382fcac | 2293 | /* |
40a0d32d | 2294 | * If the new process will be in a different pid or user namespace |
faf00da5 | 2295 | * do not allow it to share a thread group with the forking task. |
8382fcac | 2296 | */ |
faf00da5 | 2297 | if (clone_flags & CLONE_THREAD) { |
40a0d32d | 2298 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
769071ac AV |
2299 | (task_active_pid_ns(current) != nsp->pid_ns_for_children)) |
2300 | return ERR_PTR(-EINVAL); | |
2301 | } | |
2302 | ||
b3e58382 | 2303 | if (clone_flags & CLONE_PIDFD) { |
b3e58382 | 2304 | /* |
b3e58382 CB |
2305 | * - CLONE_DETACHED is blocked so that we can potentially |
2306 | * reuse it later for CLONE_PIDFD. | |
2307 | * - CLONE_THREAD is blocked until someone really needs it. | |
2308 | */ | |
7f192e3c | 2309 | if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) |
b3e58382 | 2310 | return ERR_PTR(-EINVAL); |
b3e58382 CB |
2311 | } |
2312 | ||
c3ad2c3b EB |
2313 | /* |
2314 | * Force any signals received before this point to be delivered | |
2315 | * before the fork happens. Collect up signals sent to multiple | |
2316 | * processes that happen during the fork and delay them so that | |
2317 | * they appear to happen after the fork. | |
2318 | */ | |
2319 | sigemptyset(&delayed.signal); | |
2320 | INIT_HLIST_NODE(&delayed.node); | |
2321 | ||
2322 | spin_lock_irq(¤t->sighand->siglock); | |
2323 | if (!(clone_flags & CLONE_THREAD)) | |
2324 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess); | |
2325 | recalc_sigpending(); | |
2326 | spin_unlock_irq(¤t->sighand->siglock); | |
2327 | retval = -ERESTARTNOINTR; | |
66ae0d1e | 2328 | if (task_sigpending(current)) |
c3ad2c3b EB |
2329 | goto fork_out; |
2330 | ||
1da177e4 | 2331 | retval = -ENOMEM; |
725fc629 | 2332 | p = dup_task_struct(current, node); |
1da177e4 LT |
2333 | if (!p) |
2334 | goto fork_out; | |
753550eb EB |
2335 | p->flags &= ~PF_KTHREAD; |
2336 | if (args->kthread) | |
2337 | p->flags |= PF_KTHREAD; | |
f9010dbd | 2338 | if (args->user_worker) { |
b16b3855 | 2339 | /* |
f9010dbd | 2340 | * Mark us a user worker, and block any signal that isn't |
b16b3855 JA |
2341 | * fatal or STOP |
2342 | */ | |
f9010dbd | 2343 | p->flags |= PF_USER_WORKER; |
b16b3855 JA |
2344 | siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2345 | } | |
f9010dbd MC |
2346 | if (args->io_thread) |
2347 | p->flags |= PF_IO_WORKER; | |
1da177e4 | 2348 | |
cf587db2 MC |
2349 | if (args->name) |
2350 | strscpy_pad(p->comm, args->name, sizeof(p->comm)); | |
2351 | ||
7f192e3c | 2352 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL; |
4d6501dc VN |
2353 | /* |
2354 | * Clear TID on mm_release()? | |
2355 | */ | |
7f192e3c | 2356 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL; |
4d6501dc | 2357 | |
f7e8b616 SR |
2358 | ftrace_graph_init_task(p); |
2359 | ||
bea493a0 PZ |
2360 | rt_mutex_init_task(p); |
2361 | ||
a21ee605 | 2362 | lockdep_assert_irqs_enabled(); |
d12c1a37 | 2363 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
2364 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
2365 | #endif | |
8f2f9c4d EB |
2366 | retval = copy_creds(p, clone_flags); |
2367 | if (retval < 0) | |
2368 | goto bad_fork_free; | |
2369 | ||
1da177e4 | 2370 | retval = -EAGAIN; |
de399236 | 2371 | if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { |
b57922b6 EP |
2372 | if (p->real_cred->user != INIT_USER && |
2373 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
8f2f9c4d | 2374 | goto bad_fork_cleanup_count; |
1da177e4 | 2375 | } |
72fa5997 | 2376 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 2377 | |
1da177e4 LT |
2378 | /* |
2379 | * If multiple threads are within copy_process(), then this check | |
2380 | * triggers too late. This doesn't hurt, the check is only there | |
2381 | * to stop root fork bombs. | |
2382 | */ | |
04ec93fe | 2383 | retval = -EAGAIN; |
c17d1a3a | 2384 | if (data_race(nr_threads >= max_threads)) |
1da177e4 LT |
2385 | goto bad_fork_cleanup_count; |
2386 | ||
ca74e92b | 2387 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
a8ea6fc9 | 2388 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY); |
514ddb44 | 2389 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
2390 | INIT_LIST_HEAD(&p->children); |
2391 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 2392 | rcu_copy_process(p); |
1da177e4 LT |
2393 | p->vfork_done = NULL; |
2394 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 2395 | |
1da177e4 LT |
2396 | init_sigpending(&p->pending); |
2397 | ||
64861634 | 2398 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 2399 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 2400 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 2401 | #endif |
9d7fb042 PZ |
2402 | prev_cputime_init(&p->prev_cputime); |
2403 | ||
6a61671b | 2404 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
bac5b6b6 FW |
2405 | seqcount_init(&p->vtime.seqcount); |
2406 | p->vtime.starttime = 0; | |
2407 | p->vtime.state = VTIME_INACTIVE; | |
6a61671b FW |
2408 | #endif |
2409 | ||
0f212204 JA |
2410 | #ifdef CONFIG_IO_URING |
2411 | p->io_uring = NULL; | |
2412 | #endif | |
2413 | ||
6976675d AV |
2414 | p->default_timer_slack_ns = current->timer_slack_ns; |
2415 | ||
eb414681 JW |
2416 | #ifdef CONFIG_PSI |
2417 | p->psi_flags = 0; | |
2418 | #endif | |
2419 | ||
5995477a | 2420 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
2421 | acct_clear_integrals(p); |
2422 | ||
3a245c0f | 2423 | posix_cputimers_init(&p->posix_cputimers); |
1da177e4 | 2424 | |
1da177e4 | 2425 | p->io_context = NULL; |
c0b0ae8a | 2426 | audit_set_context(p, NULL); |
b4f48b63 | 2427 | cgroup_fork(p); |
343f4c49 | 2428 | if (args->kthread) { |
40966e31 | 2429 | if (!set_kthread_struct(p)) |
ff8288ff | 2430 | goto bad_fork_cleanup_delayacct; |
40966e31 | 2431 | } |
1da177e4 | 2432 | #ifdef CONFIG_NUMA |
846a16bf | 2433 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
2434 | if (IS_ERR(p->mempolicy)) { |
2435 | retval = PTR_ERR(p->mempolicy); | |
2436 | p->mempolicy = NULL; | |
ff8288ff | 2437 | goto bad_fork_cleanup_delayacct; |
fb0a685c | 2438 | } |
1da177e4 | 2439 | #endif |
778d3b0f MH |
2440 | #ifdef CONFIG_CPUSETS |
2441 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
2442 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
b7505861 | 2443 | seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock); |
778d3b0f | 2444 | #endif |
de30a2b3 | 2445 | #ifdef CONFIG_TRACE_IRQFLAGS |
0584df9c ME |
2446 | memset(&p->irqtrace, 0, sizeof(p->irqtrace)); |
2447 | p->irqtrace.hardirq_disable_ip = _THIS_IP_; | |
2448 | p->irqtrace.softirq_enable_ip = _THIS_IP_; | |
2449 | p->softirqs_enabled = 1; | |
2450 | p->softirq_context = 0; | |
de30a2b3 | 2451 | #endif |
8bcbde54 DH |
2452 | |
2453 | p->pagefault_disabled = 0; | |
2454 | ||
fbb9ce95 | 2455 | #ifdef CONFIG_LOCKDEP |
b09be676 | 2456 | lockdep_init_task(p); |
fbb9ce95 | 2457 | #endif |
1da177e4 | 2458 | |
408894ee IM |
2459 | #ifdef CONFIG_DEBUG_MUTEXES |
2460 | p->blocked_on = NULL; /* not blocked yet */ | |
2461 | #endif | |
cafe5635 KO |
2462 | #ifdef CONFIG_BCACHE |
2463 | p->sequential_io = 0; | |
2464 | p->sequential_io_avg = 0; | |
2465 | #endif | |
a10787e6 SL |
2466 | #ifdef CONFIG_BPF_SYSCALL |
2467 | RCU_INIT_POINTER(p->bpf_storage, NULL); | |
c7603cfa | 2468 | p->bpf_ctx = NULL; |
a10787e6 | 2469 | #endif |
0f481406 | 2470 | |
3c90e6e9 | 2471 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
2472 | retval = sched_fork(clone_flags, p); |
2473 | if (retval) | |
2474 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 2475 | |
2b26f0aa | 2476 | retval = perf_event_init_task(p, clone_flags); |
6ab423e0 PZ |
2477 | if (retval) |
2478 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
2479 | retval = audit_alloc(p); |
2480 | if (retval) | |
6c72e350 | 2481 | goto bad_fork_cleanup_perf; |
1da177e4 | 2482 | /* copy all the process information */ |
ab602f79 | 2483 | shm_init_task(p); |
e4e55b47 | 2484 | retval = security_task_alloc(p, clone_flags); |
fb0a685c | 2485 | if (retval) |
1da177e4 | 2486 | goto bad_fork_cleanup_audit; |
e4e55b47 TH |
2487 | retval = copy_semundo(clone_flags, p); |
2488 | if (retval) | |
2489 | goto bad_fork_cleanup_security; | |
11f3f500 | 2490 | retval = copy_files(clone_flags, p, args->no_files); |
fb0a685c | 2491 | if (retval) |
1da177e4 | 2492 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
2493 | retval = copy_fs(clone_flags, p); |
2494 | if (retval) | |
1da177e4 | 2495 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
2496 | retval = copy_sighand(clone_flags, p); |
2497 | if (retval) | |
1da177e4 | 2498 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
2499 | retval = copy_signal(clone_flags, p); |
2500 | if (retval) | |
1da177e4 | 2501 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
2502 | retval = copy_mm(clone_flags, p); |
2503 | if (retval) | |
1da177e4 | 2504 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
2505 | retval = copy_namespaces(clone_flags, p); |
2506 | if (retval) | |
d84f4f99 | 2507 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
2508 | retval = copy_io(clone_flags, p); |
2509 | if (retval) | |
fd0928df | 2510 | goto bad_fork_cleanup_namespaces; |
c5febea0 | 2511 | retval = copy_thread(p, args); |
1da177e4 | 2512 | if (retval) |
fd0928df | 2513 | goto bad_fork_cleanup_io; |
1da177e4 | 2514 | |
afaef01c AP |
2515 | stackleak_task_init(p); |
2516 | ||
425fb2b4 | 2517 | if (pid != &init_struct_pid) { |
49cb2fc4 AR |
2518 | pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid, |
2519 | args->set_tid_size); | |
35f71bc0 MH |
2520 | if (IS_ERR(pid)) { |
2521 | retval = PTR_ERR(pid); | |
0740aa5f | 2522 | goto bad_fork_cleanup_thread; |
35f71bc0 | 2523 | } |
425fb2b4 PE |
2524 | } |
2525 | ||
b3e58382 CB |
2526 | /* |
2527 | * This has to happen after we've potentially unshared the file | |
2528 | * descriptor table (so that the pidfd doesn't leak into the child | |
2529 | * if the fd table isn't shared). | |
2530 | */ | |
2531 | if (clone_flags & CLONE_PIDFD) { | |
ca7707f5 CB |
2532 | /* Note that no task has been attached to @pid yet. */ |
2533 | retval = __pidfd_prepare(pid, O_RDWR | O_CLOEXEC, &pidfile); | |
b3e58382 CB |
2534 | if (retval < 0) |
2535 | goto bad_fork_free_pid; | |
b3e58382 | 2536 | pidfd = retval; |
6fd2fe49 | 2537 | |
7f192e3c | 2538 | retval = put_user(pidfd, args->pidfd); |
b3e58382 CB |
2539 | if (retval) |
2540 | goto bad_fork_put_pidfd; | |
2541 | } | |
2542 | ||
73c10101 JA |
2543 | #ifdef CONFIG_BLOCK |
2544 | p->plug = NULL; | |
2545 | #endif | |
ba31c1a4 TG |
2546 | futex_init_task(p); |
2547 | ||
f9a3879a GM |
2548 | /* |
2549 | * sigaltstack should be cleared when sharing the same VM | |
2550 | */ | |
2551 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 2552 | sas_ss_reset(p); |
f9a3879a | 2553 | |
1da177e4 | 2554 | /* |
6580807d ON |
2555 | * Syscall tracing and stepping should be turned off in the |
2556 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 2557 | */ |
6580807d | 2558 | user_disable_single_step(p); |
64c19ba2 | 2559 | clear_task_syscall_work(p, SYSCALL_TRACE); |
64eb35f7 GKB |
2560 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) |
2561 | clear_task_syscall_work(p, SYSCALL_EMU); | |
ed75e8d5 | 2562 | #endif |
e02c9b0d | 2563 | clear_tsk_latency_tracing(p); |
1da177e4 | 2564 | |
1da177e4 | 2565 | /* ok, now we should be set up.. */ |
18c830df ON |
2566 | p->pid = pid_nr(pid); |
2567 | if (clone_flags & CLONE_THREAD) { | |
18c830df ON |
2568 | p->group_leader = current->group_leader; |
2569 | p->tgid = current->tgid; | |
2570 | } else { | |
18c830df ON |
2571 | p->group_leader = p; |
2572 | p->tgid = p->pid; | |
2573 | } | |
5f8aadd8 | 2574 | |
9d823e8f WF |
2575 | p->nr_dirtied = 0; |
2576 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 2577 | p->dirty_paused_when = 0; |
9d823e8f | 2578 | |
bb8cbbfe | 2579 | p->pdeath_signal = 0; |
158e1645 | 2580 | p->task_works = NULL; |
ca7752ca | 2581 | clear_posix_cputimers_work(p); |
1da177e4 | 2582 | |
d741bf41 PZ |
2583 | #ifdef CONFIG_KRETPROBES |
2584 | p->kretprobe_instances.first = NULL; | |
2585 | #endif | |
54ecbe6f MH |
2586 | #ifdef CONFIG_RETHOOK |
2587 | p->rethooks.first = NULL; | |
2588 | #endif | |
d741bf41 | 2589 | |
7e47682e AS |
2590 | /* |
2591 | * Ensure that the cgroup subsystem policies allow the new process to be | |
7b7b8a2c | 2592 | * forked. It should be noted that the new process's css_set can be changed |
7e47682e AS |
2593 | * between here and cgroup_post_fork() if an organisation operation is in |
2594 | * progress. | |
2595 | */ | |
ef2c41cf | 2596 | retval = cgroup_can_fork(p, args); |
7e47682e | 2597 | if (retval) |
5a5cf5cb | 2598 | goto bad_fork_put_pidfd; |
7e47682e | 2599 | |
b1e82065 PZ |
2600 | /* |
2601 | * Now that the cgroups are pinned, re-clone the parent cgroup and put | |
2602 | * the new task on the correct runqueue. All this *before* the task | |
2603 | * becomes visible. | |
2604 | * | |
2605 | * This isn't part of ->can_fork() because while the re-cloning is | |
2606 | * cgroup specific, it unconditionally needs to place the task on a | |
2607 | * runqueue. | |
2608 | */ | |
2609 | sched_cgroup_fork(p, args); | |
2610 | ||
7b558513 DH |
2611 | /* |
2612 | * From this point on we must avoid any synchronous user-space | |
2613 | * communication until we take the tasklist-lock. In particular, we do | |
2614 | * not want user-space to be able to predict the process start-time by | |
2615 | * stalling fork(2) after we recorded the start_time but before it is | |
2616 | * visible to the system. | |
2617 | */ | |
2618 | ||
2619 | p->start_time = ktime_get_ns(); | |
cf25e24d | 2620 | p->start_boottime = ktime_get_boottime_ns(); |
7b558513 | 2621 | |
18c830df ON |
2622 | /* |
2623 | * Make it visible to the rest of the system, but dont wake it up yet. | |
2624 | * Need tasklist lock for parent etc handling! | |
2625 | */ | |
1da177e4 LT |
2626 | write_lock_irq(&tasklist_lock); |
2627 | ||
1da177e4 | 2628 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 2629 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 2630 | p->real_parent = current->real_parent; |
2d5516cb | 2631 | p->parent_exec_id = current->parent_exec_id; |
b4e00444 EW |
2632 | if (clone_flags & CLONE_THREAD) |
2633 | p->exit_signal = -1; | |
2634 | else | |
2635 | p->exit_signal = current->group_leader->exit_signal; | |
2d5516cb | 2636 | } else { |
1da177e4 | 2637 | p->real_parent = current; |
2d5516cb | 2638 | p->parent_exec_id = current->self_exec_id; |
b4e00444 | 2639 | p->exit_signal = args->exit_signal; |
2d5516cb | 2640 | } |
1da177e4 | 2641 | |
d83a7cb3 JP |
2642 | klp_copy_process(p); |
2643 | ||
85dd3f61 PZ |
2644 | sched_core_fork(p); |
2645 | ||
3f17da69 | 2646 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 2647 | |
79257534 DBO |
2648 | rv_task_fork(p); |
2649 | ||
d7822b1e MD |
2650 | rseq_fork(p, clone_flags); |
2651 | ||
4ca1d3ee | 2652 | /* Don't start children in a dying pid namespace */ |
e8cfbc24 | 2653 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { |
3fd37226 KT |
2654 | retval = -ENOMEM; |
2655 | goto bad_fork_cancel_cgroup; | |
2656 | } | |
4a2c7a78 | 2657 | |
7673bf55 EB |
2658 | /* Let kill terminate clone/fork in the middle */ |
2659 | if (fatal_signal_pending(current)) { | |
2660 | retval = -EINTR; | |
2661 | goto bad_fork_cancel_cgroup; | |
2662 | } | |
2663 | ||
a1140cb2 KI |
2664 | /* No more failure paths after this point. */ |
2665 | ||
2666 | /* | |
2667 | * Copy seccomp details explicitly here, in case they were changed | |
2668 | * before holding sighand lock. | |
2669 | */ | |
2670 | copy_seccomp(p); | |
2671 | ||
2c470475 | 2672 | init_task_pid_links(p); |
73b9ebfe | 2673 | if (likely(p->pid)) { |
4b9d33e6 | 2674 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 2675 | |
81907739 | 2676 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 2677 | if (thread_group_leader(p)) { |
6883f81a | 2678 | init_task_pid(p, PIDTYPE_TGID, pid); |
81907739 ON |
2679 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
2680 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
2681 | ||
1c4042c2 | 2682 | if (is_child_reaper(pid)) { |
17cf22c3 | 2683 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
2684 | p->signal->flags |= SIGNAL_UNKILLABLE; |
2685 | } | |
c3ad2c3b | 2686 | p->signal->shared_pending.signal = delayed.signal; |
9c9f4ded | 2687 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
2688 | /* |
2689 | * Inherit has_child_subreaper flag under the same | |
2690 | * tasklist_lock with adding child to the process tree | |
2691 | * for propagate_has_child_subreaper optimization. | |
2692 | */ | |
2693 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
2694 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 2695 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 2696 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
6883f81a | 2697 | attach_pid(p, PIDTYPE_TGID); |
81907739 ON |
2698 | attach_pid(p, PIDTYPE_PGID); |
2699 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 2700 | __this_cpu_inc(process_counts); |
80628ca0 ON |
2701 | } else { |
2702 | current->signal->nr_threads++; | |
d80f7d7b | 2703 | current->signal->quick_threads++; |
80628ca0 | 2704 | atomic_inc(¤t->signal->live); |
60d4de3f | 2705 | refcount_inc(¤t->signal->sigcnt); |
924de3b8 | 2706 | task_join_group_stop(p); |
0c740d0a ON |
2707 | list_add_tail_rcu(&p->thread_node, |
2708 | &p->signal->thread_head); | |
73b9ebfe | 2709 | } |
81907739 | 2710 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 2711 | nr_threads++; |
1da177e4 | 2712 | } |
1da177e4 | 2713 | total_forks++; |
c3ad2c3b | 2714 | hlist_del_init(&delayed.node); |
3f17da69 | 2715 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 2716 | syscall_tracepoint_update(p); |
1da177e4 | 2717 | write_unlock_irq(&tasklist_lock); |
4af4206b | 2718 | |
ddc204b5 WL |
2719 | if (pidfile) |
2720 | fd_install(pidfd, pidfile); | |
2721 | ||
c13cf856 | 2722 | proc_fork_connector(p); |
b1e82065 | 2723 | sched_post_fork(p); |
ef2c41cf | 2724 | cgroup_post_fork(p, args); |
cdd6c482 | 2725 | perf_event_fork(p); |
43d2b113 KH |
2726 | |
2727 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 2728 | uprobe_copy_process(p, clone_flags); |
fd593511 | 2729 | user_events_fork(p, clone_flags); |
43d2b113 | 2730 | |
67197a4f SB |
2731 | copy_oom_score_adj(clone_flags, p); |
2732 | ||
1da177e4 LT |
2733 | return p; |
2734 | ||
7e47682e | 2735 | bad_fork_cancel_cgroup: |
85dd3f61 | 2736 | sched_core_free(p); |
3fd37226 KT |
2737 | spin_unlock(¤t->sighand->siglock); |
2738 | write_unlock_irq(&tasklist_lock); | |
ef2c41cf | 2739 | cgroup_cancel_fork(p, args); |
b3e58382 | 2740 | bad_fork_put_pidfd: |
6fd2fe49 AV |
2741 | if (clone_flags & CLONE_PIDFD) { |
2742 | fput(pidfile); | |
2743 | put_unused_fd(pidfd); | |
2744 | } | |
425fb2b4 PE |
2745 | bad_fork_free_pid: |
2746 | if (pid != &init_struct_pid) | |
2747 | free_pid(pid); | |
0740aa5f JS |
2748 | bad_fork_cleanup_thread: |
2749 | exit_thread(p); | |
fd0928df | 2750 | bad_fork_cleanup_io: |
b69f2292 LR |
2751 | if (p->io_context) |
2752 | exit_io_context(p); | |
ab516013 | 2753 | bad_fork_cleanup_namespaces: |
444f378b | 2754 | exit_task_namespaces(p); |
1da177e4 | 2755 | bad_fork_cleanup_mm: |
c3f3ce04 AA |
2756 | if (p->mm) { |
2757 | mm_clear_owner(p->mm, p); | |
1da177e4 | 2758 | mmput(p->mm); |
c3f3ce04 | 2759 | } |
1da177e4 | 2760 | bad_fork_cleanup_signal: |
4ab6c083 | 2761 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 2762 | free_signal_struct(p->signal); |
1da177e4 | 2763 | bad_fork_cleanup_sighand: |
a7e5328a | 2764 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
2765 | bad_fork_cleanup_fs: |
2766 | exit_fs(p); /* blocking */ | |
2767 | bad_fork_cleanup_files: | |
2768 | exit_files(p); /* blocking */ | |
2769 | bad_fork_cleanup_semundo: | |
2770 | exit_sem(p); | |
e4e55b47 TH |
2771 | bad_fork_cleanup_security: |
2772 | security_task_free(p); | |
1da177e4 LT |
2773 | bad_fork_cleanup_audit: |
2774 | audit_free(p); | |
6c72e350 | 2775 | bad_fork_cleanup_perf: |
cdd6c482 | 2776 | perf_event_free_task(p); |
6c72e350 | 2777 | bad_fork_cleanup_policy: |
b09be676 | 2778 | lockdep_free_task(p); |
1da177e4 | 2779 | #ifdef CONFIG_NUMA |
f0be3d32 | 2780 | mpol_put(p->mempolicy); |
1da177e4 | 2781 | #endif |
ff8288ff | 2782 | bad_fork_cleanup_delayacct: |
35df17c5 | 2783 | delayacct_tsk_free(p); |
1da177e4 | 2784 | bad_fork_cleanup_count: |
21d1c5e3 | 2785 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); |
e0e81739 | 2786 | exit_creds(p); |
1da177e4 | 2787 | bad_fork_free: |
2f064a59 | 2788 | WRITE_ONCE(p->__state, TASK_DEAD); |
1a03d3f1 | 2789 | exit_task_stack_account(p); |
68f24b08 | 2790 | put_task_stack(p); |
c3f3ce04 | 2791 | delayed_free_task(p); |
fe7d37d1 | 2792 | fork_out: |
c3ad2c3b EB |
2793 | spin_lock_irq(¤t->sighand->siglock); |
2794 | hlist_del_init(&delayed.node); | |
2795 | spin_unlock_irq(¤t->sighand->siglock); | |
fe7d37d1 | 2796 | return ERR_PTR(retval); |
1da177e4 LT |
2797 | } |
2798 | ||
2c470475 | 2799 | static inline void init_idle_pids(struct task_struct *idle) |
f106eee1 ON |
2800 | { |
2801 | enum pid_type type; | |
2802 | ||
2803 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
2c470475 EB |
2804 | INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */ |
2805 | init_task_pid(idle, type, &init_struct_pid); | |
f106eee1 ON |
2806 | } |
2807 | } | |
2808 | ||
36cb0e1c EB |
2809 | static int idle_dummy(void *dummy) |
2810 | { | |
2811 | /* This function is never called */ | |
2812 | return 0; | |
2813 | } | |
2814 | ||
f1a0a376 | 2815 | struct task_struct * __init fork_idle(int cpu) |
1da177e4 | 2816 | { |
36c8b586 | 2817 | struct task_struct *task; |
7f192e3c | 2818 | struct kernel_clone_args args = { |
343f4c49 | 2819 | .flags = CLONE_VM, |
5bd2e97c EB |
2820 | .fn = &idle_dummy, |
2821 | .fn_arg = NULL, | |
343f4c49 | 2822 | .kthread = 1, |
36cb0e1c | 2823 | .idle = 1, |
7f192e3c CB |
2824 | }; |
2825 | ||
2826 | task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args); | |
f106eee1 | 2827 | if (!IS_ERR(task)) { |
2c470475 | 2828 | init_idle_pids(task); |
753ca4f3 | 2829 | init_idle(task, cpu); |
f106eee1 | 2830 | } |
73b9ebfe | 2831 | |
1da177e4 LT |
2832 | return task; |
2833 | } | |
2834 | ||
cc440e87 JA |
2835 | /* |
2836 | * This is like kernel_clone(), but shaved down and tailored to just | |
2837 | * creating io_uring workers. It returns a created task, or an error pointer. | |
2838 | * The returned task is inactive, and the caller must fire it up through | |
2839 | * wake_up_new_task(p). All signals are blocked in the created task. | |
2840 | */ | |
2841 | struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) | |
2842 | { | |
2843 | unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD| | |
2844 | CLONE_IO; | |
2845 | struct kernel_clone_args args = { | |
2846 | .flags = ((lower_32_bits(flags) | CLONE_VM | | |
2847 | CLONE_UNTRACED) & ~CSIGNAL), | |
2848 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2849 | .fn = fn, |
2850 | .fn_arg = arg, | |
cc440e87 | 2851 | .io_thread = 1, |
54e6842d | 2852 | .user_worker = 1, |
cc440e87 | 2853 | }; |
cc440e87 | 2854 | |
b16b3855 | 2855 | return copy_process(NULL, 0, node, &args); |
cc440e87 JA |
2856 | } |
2857 | ||
1da177e4 LT |
2858 | /* |
2859 | * Ok, this is the main fork-routine. | |
2860 | * | |
2861 | * It copies the process, and if successful kick-starts | |
2862 | * it and waits for it to finish using the VM if required. | |
a0eb9abd ES |
2863 | * |
2864 | * args->exit_signal is expected to be checked for sanity by the caller. | |
1da177e4 | 2865 | */ |
cad6967a | 2866 | pid_t kernel_clone(struct kernel_clone_args *args) |
1da177e4 | 2867 | { |
7f192e3c | 2868 | u64 clone_flags = args->flags; |
9f5325aa MPS |
2869 | struct completion vfork; |
2870 | struct pid *pid; | |
1da177e4 LT |
2871 | struct task_struct *p; |
2872 | int trace = 0; | |
cad6967a | 2873 | pid_t nr; |
1da177e4 | 2874 | |
3af8588c CB |
2875 | /* |
2876 | * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument | |
2877 | * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are | |
2878 | * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate | |
2879 | * field in struct clone_args and it still doesn't make sense to have | |
2880 | * them both point at the same memory location. Performing this check | |
2881 | * here has the advantage that we don't need to have a separate helper | |
2882 | * to check for legacy clone(). | |
2883 | */ | |
2884 | if ((args->flags & CLONE_PIDFD) && | |
2885 | (args->flags & CLONE_PARENT_SETTID) && | |
2886 | (args->pidfd == args->parent_tid)) | |
2887 | return -EINVAL; | |
2888 | ||
09a05394 | 2889 | /* |
4b9d33e6 TH |
2890 | * Determine whether and which event to report to ptracer. When |
2891 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
2892 | * requested, no event is reported; otherwise, report if the event | |
2893 | * for the type of forking is enabled. | |
09a05394 | 2894 | */ |
e80d6661 | 2895 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
2896 | if (clone_flags & CLONE_VFORK) |
2897 | trace = PTRACE_EVENT_VFORK; | |
7f192e3c | 2898 | else if (args->exit_signal != SIGCHLD) |
4b9d33e6 TH |
2899 | trace = PTRACE_EVENT_CLONE; |
2900 | else | |
2901 | trace = PTRACE_EVENT_FORK; | |
2902 | ||
2903 | if (likely(!ptrace_event_enabled(current, trace))) | |
2904 | trace = 0; | |
2905 | } | |
1da177e4 | 2906 | |
7f192e3c | 2907 | p = copy_process(NULL, trace, NUMA_NO_NODE, args); |
38addce8 | 2908 | add_latent_entropy(); |
9f5325aa MPS |
2909 | |
2910 | if (IS_ERR(p)) | |
2911 | return PTR_ERR(p); | |
2912 | ||
1da177e4 LT |
2913 | /* |
2914 | * Do this prior waking up the new thread - the thread pointer | |
2915 | * might get invalid after that point, if the thread exits quickly. | |
2916 | */ | |
9f5325aa | 2917 | trace_sched_process_fork(current, p); |
0a16b607 | 2918 | |
9f5325aa MPS |
2919 | pid = get_task_pid(p, PIDTYPE_PID); |
2920 | nr = pid_vnr(pid); | |
30e49c26 | 2921 | |
9f5325aa | 2922 | if (clone_flags & CLONE_PARENT_SETTID) |
7f192e3c | 2923 | put_user(nr, args->parent_tid); |
a6f5e063 | 2924 | |
9f5325aa MPS |
2925 | if (clone_flags & CLONE_VFORK) { |
2926 | p->vfork_done = &vfork; | |
2927 | init_completion(&vfork); | |
2928 | get_task_struct(p); | |
2929 | } | |
1da177e4 | 2930 | |
bd74fdae YZ |
2931 | if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) { |
2932 | /* lock the task to synchronize with memcg migration */ | |
2933 | task_lock(p); | |
2934 | lru_gen_add_mm(p->mm); | |
2935 | task_unlock(p); | |
2936 | } | |
2937 | ||
9f5325aa | 2938 | wake_up_new_task(p); |
09a05394 | 2939 | |
9f5325aa MPS |
2940 | /* forking complete and child started to run, tell ptracer */ |
2941 | if (unlikely(trace)) | |
2942 | ptrace_event_pid(trace, pid); | |
4e52365f | 2943 | |
9f5325aa MPS |
2944 | if (clone_flags & CLONE_VFORK) { |
2945 | if (!wait_for_vfork_done(p, &vfork)) | |
2946 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); | |
1da177e4 | 2947 | } |
9f5325aa MPS |
2948 | |
2949 | put_pid(pid); | |
92476d7f | 2950 | return nr; |
1da177e4 LT |
2951 | } |
2952 | ||
2aa3a7f8 AV |
2953 | /* |
2954 | * Create a kernel thread. | |
2955 | */ | |
cf587db2 MC |
2956 | pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name, |
2957 | unsigned long flags) | |
2aa3a7f8 | 2958 | { |
7f192e3c | 2959 | struct kernel_clone_args args = { |
3f2c788a CB |
2960 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2961 | CLONE_UNTRACED) & ~CSIGNAL), | |
2962 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2963 | .fn = fn, |
2964 | .fn_arg = arg, | |
cf587db2 | 2965 | .name = name, |
343f4c49 EB |
2966 | .kthread = 1, |
2967 | }; | |
2968 | ||
2969 | return kernel_clone(&args); | |
2970 | } | |
2971 | ||
2972 | /* | |
2973 | * Create a user mode thread. | |
2974 | */ | |
2975 | pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2aa3a7f8 | 2976 | { |
7f192e3c | 2977 | struct kernel_clone_args args = { |
3f2c788a CB |
2978 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2979 | CLONE_UNTRACED) & ~CSIGNAL), | |
2980 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2981 | .fn = fn, |
2982 | .fn_arg = arg, | |
7f192e3c CB |
2983 | }; |
2984 | ||
cad6967a | 2985 | return kernel_clone(&args); |
2aa3a7f8 | 2986 | } |
2aa3a7f8 | 2987 | |
d2125043 AV |
2988 | #ifdef __ARCH_WANT_SYS_FORK |
2989 | SYSCALL_DEFINE0(fork) | |
2990 | { | |
2991 | #ifdef CONFIG_MMU | |
7f192e3c CB |
2992 | struct kernel_clone_args args = { |
2993 | .exit_signal = SIGCHLD, | |
2994 | }; | |
2995 | ||
cad6967a | 2996 | return kernel_clone(&args); |
d2125043 AV |
2997 | #else |
2998 | /* can not support in nommu mode */ | |
5d59e182 | 2999 | return -EINVAL; |
d2125043 AV |
3000 | #endif |
3001 | } | |
3002 | #endif | |
3003 | ||
3004 | #ifdef __ARCH_WANT_SYS_VFORK | |
3005 | SYSCALL_DEFINE0(vfork) | |
3006 | { | |
7f192e3c CB |
3007 | struct kernel_clone_args args = { |
3008 | .flags = CLONE_VFORK | CLONE_VM, | |
3009 | .exit_signal = SIGCHLD, | |
3010 | }; | |
3011 | ||
cad6967a | 3012 | return kernel_clone(&args); |
d2125043 AV |
3013 | } |
3014 | #endif | |
3015 | ||
3016 | #ifdef __ARCH_WANT_SYS_CLONE | |
3017 | #ifdef CONFIG_CLONE_BACKWARDS | |
3018 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
3019 | int __user *, parent_tidptr, | |
3033f14a | 3020 | unsigned long, tls, |
d2125043 AV |
3021 | int __user *, child_tidptr) |
3022 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
3023 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
3024 | int __user *, parent_tidptr, | |
3025 | int __user *, child_tidptr, | |
3033f14a | 3026 | unsigned long, tls) |
dfa9771a MS |
3027 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
3028 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
3029 | int, stack_size, | |
3030 | int __user *, parent_tidptr, | |
3031 | int __user *, child_tidptr, | |
3033f14a | 3032 | unsigned long, tls) |
d2125043 AV |
3033 | #else |
3034 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
3035 | int __user *, parent_tidptr, | |
3036 | int __user *, child_tidptr, | |
3033f14a | 3037 | unsigned long, tls) |
d2125043 AV |
3038 | #endif |
3039 | { | |
7f192e3c | 3040 | struct kernel_clone_args args = { |
3f2c788a | 3041 | .flags = (lower_32_bits(clone_flags) & ~CSIGNAL), |
7f192e3c CB |
3042 | .pidfd = parent_tidptr, |
3043 | .child_tid = child_tidptr, | |
3044 | .parent_tid = parent_tidptr, | |
3f2c788a | 3045 | .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL), |
7f192e3c CB |
3046 | .stack = newsp, |
3047 | .tls = tls, | |
3048 | }; | |
3049 | ||
cad6967a | 3050 | return kernel_clone(&args); |
7f192e3c | 3051 | } |
d68dbb0c | 3052 | #endif |
7f192e3c | 3053 | |
d68dbb0c | 3054 | #ifdef __ARCH_WANT_SYS_CLONE3 |
dd499f7a | 3055 | |
7f192e3c CB |
3056 | noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, |
3057 | struct clone_args __user *uargs, | |
f14c234b | 3058 | size_t usize) |
7f192e3c | 3059 | { |
f14c234b | 3060 | int err; |
7f192e3c | 3061 | struct clone_args args; |
49cb2fc4 | 3062 | pid_t *kset_tid = kargs->set_tid; |
7f192e3c | 3063 | |
a966dcfe ES |
3064 | BUILD_BUG_ON(offsetofend(struct clone_args, tls) != |
3065 | CLONE_ARGS_SIZE_VER0); | |
3066 | BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) != | |
3067 | CLONE_ARGS_SIZE_VER1); | |
3068 | BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != | |
3069 | CLONE_ARGS_SIZE_VER2); | |
3070 | BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); | |
3071 | ||
f14c234b | 3072 | if (unlikely(usize > PAGE_SIZE)) |
7f192e3c | 3073 | return -E2BIG; |
f14c234b | 3074 | if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) |
7f192e3c CB |
3075 | return -EINVAL; |
3076 | ||
f14c234b AS |
3077 | err = copy_struct_from_user(&args, sizeof(args), uargs, usize); |
3078 | if (err) | |
3079 | return err; | |
7f192e3c | 3080 | |
49cb2fc4 AR |
3081 | if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL)) |
3082 | return -EINVAL; | |
3083 | ||
3084 | if (unlikely(!args.set_tid && args.set_tid_size > 0)) | |
3085 | return -EINVAL; | |
3086 | ||
3087 | if (unlikely(args.set_tid && args.set_tid_size == 0)) | |
3088 | return -EINVAL; | |
3089 | ||
a0eb9abd ES |
3090 | /* |
3091 | * Verify that higher 32bits of exit_signal are unset and that | |
3092 | * it is a valid signal | |
3093 | */ | |
3094 | if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) || | |
3095 | !valid_signal(args.exit_signal))) | |
3096 | return -EINVAL; | |
3097 | ||
62173872 ES |
3098 | if ((args.flags & CLONE_INTO_CGROUP) && |
3099 | (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2)) | |
ef2c41cf CB |
3100 | return -EINVAL; |
3101 | ||
7f192e3c CB |
3102 | *kargs = (struct kernel_clone_args){ |
3103 | .flags = args.flags, | |
3104 | .pidfd = u64_to_user_ptr(args.pidfd), | |
3105 | .child_tid = u64_to_user_ptr(args.child_tid), | |
3106 | .parent_tid = u64_to_user_ptr(args.parent_tid), | |
3107 | .exit_signal = args.exit_signal, | |
3108 | .stack = args.stack, | |
3109 | .stack_size = args.stack_size, | |
3110 | .tls = args.tls, | |
49cb2fc4 | 3111 | .set_tid_size = args.set_tid_size, |
ef2c41cf | 3112 | .cgroup = args.cgroup, |
7f192e3c CB |
3113 | }; |
3114 | ||
49cb2fc4 AR |
3115 | if (args.set_tid && |
3116 | copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid), | |
3117 | (kargs->set_tid_size * sizeof(pid_t)))) | |
3118 | return -EFAULT; | |
3119 | ||
3120 | kargs->set_tid = kset_tid; | |
3121 | ||
7f192e3c CB |
3122 | return 0; |
3123 | } | |
3124 | ||
fa729c4d CB |
3125 | /** |
3126 | * clone3_stack_valid - check and prepare stack | |
3127 | * @kargs: kernel clone args | |
3128 | * | |
3129 | * Verify that the stack arguments userspace gave us are sane. | |
3130 | * In addition, set the stack direction for userspace since it's easy for us to | |
3131 | * determine. | |
3132 | */ | |
3133 | static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) | |
3134 | { | |
3135 | if (kargs->stack == 0) { | |
3136 | if (kargs->stack_size > 0) | |
3137 | return false; | |
3138 | } else { | |
3139 | if (kargs->stack_size == 0) | |
3140 | return false; | |
3141 | ||
3142 | if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) | |
3143 | return false; | |
3144 | ||
cf8e8658 | 3145 | #if !defined(CONFIG_STACK_GROWSUP) |
fa729c4d CB |
3146 | kargs->stack += kargs->stack_size; |
3147 | #endif | |
3148 | } | |
3149 | ||
3150 | return true; | |
3151 | } | |
3152 | ||
3153 | static bool clone3_args_valid(struct kernel_clone_args *kargs) | |
7f192e3c | 3154 | { |
b612e5df | 3155 | /* Verify that no unknown flags are passed along. */ |
ef2c41cf CB |
3156 | if (kargs->flags & |
3157 | ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP)) | |
7f192e3c CB |
3158 | return false; |
3159 | ||
3160 | /* | |
a8ca6b13 XC |
3161 | * - make the CLONE_DETACHED bit reusable for clone3 |
3162 | * - make the CSIGNAL bits reusable for clone3 | |
7f192e3c | 3163 | */ |
a402f1e3 | 3164 | if (kargs->flags & (CLONE_DETACHED | (CSIGNAL & (~CLONE_NEWTIME)))) |
7f192e3c CB |
3165 | return false; |
3166 | ||
b612e5df CB |
3167 | if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) == |
3168 | (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) | |
3169 | return false; | |
3170 | ||
7f192e3c CB |
3171 | if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) && |
3172 | kargs->exit_signal) | |
3173 | return false; | |
3174 | ||
fa729c4d CB |
3175 | if (!clone3_stack_valid(kargs)) |
3176 | return false; | |
3177 | ||
7f192e3c CB |
3178 | return true; |
3179 | } | |
3180 | ||
501bd016 | 3181 | /** |
ff0712ea | 3182 | * sys_clone3 - create a new process with specific properties |
501bd016 CB |
3183 | * @uargs: argument structure |
3184 | * @size: size of @uargs | |
3185 | * | |
3186 | * clone3() is the extensible successor to clone()/clone2(). | |
3187 | * It takes a struct as argument that is versioned by its size. | |
3188 | * | |
3189 | * Return: On success, a positive PID for the child process. | |
3190 | * On error, a negative errno number. | |
3191 | */ | |
7f192e3c CB |
3192 | SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) |
3193 | { | |
3194 | int err; | |
3195 | ||
3196 | struct kernel_clone_args kargs; | |
49cb2fc4 AR |
3197 | pid_t set_tid[MAX_PID_NS_LEVEL]; |
3198 | ||
3199 | kargs.set_tid = set_tid; | |
7f192e3c CB |
3200 | |
3201 | err = copy_clone_args_from_user(&kargs, uargs, size); | |
3202 | if (err) | |
3203 | return err; | |
3204 | ||
3205 | if (!clone3_args_valid(&kargs)) | |
3206 | return -EINVAL; | |
3207 | ||
cad6967a | 3208 | return kernel_clone(&kargs); |
d2125043 AV |
3209 | } |
3210 | #endif | |
3211 | ||
0f1b92cb ON |
3212 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
3213 | { | |
3214 | struct task_struct *leader, *parent, *child; | |
3215 | int res; | |
3216 | ||
3217 | read_lock(&tasklist_lock); | |
3218 | leader = top = top->group_leader; | |
3219 | down: | |
3220 | for_each_thread(leader, parent) { | |
3221 | list_for_each_entry(child, &parent->children, sibling) { | |
3222 | res = visitor(child, data); | |
3223 | if (res) { | |
3224 | if (res < 0) | |
3225 | goto out; | |
3226 | leader = child; | |
3227 | goto down; | |
3228 | } | |
3229 | up: | |
3230 | ; | |
3231 | } | |
3232 | } | |
3233 | ||
3234 | if (leader != top) { | |
3235 | child = leader; | |
3236 | parent = child->real_parent; | |
3237 | leader = parent->group_leader; | |
3238 | goto up; | |
3239 | } | |
3240 | out: | |
3241 | read_unlock(&tasklist_lock); | |
3242 | } | |
3243 | ||
5fd63b30 RT |
3244 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
3245 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
3246 | #endif | |
3247 | ||
51cc5068 | 3248 | static void sighand_ctor(void *data) |
aa1757f9 ON |
3249 | { |
3250 | struct sighand_struct *sighand = data; | |
3251 | ||
a35afb83 | 3252 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 3253 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
3254 | } |
3255 | ||
af806027 | 3256 | void __init mm_cache_init(void) |
1da177e4 | 3257 | { |
c1a2f7f0 RR |
3258 | unsigned int mm_size; |
3259 | ||
af806027 PZ |
3260 | /* |
3261 | * The mm_cpumask is located at the end of mm_struct, and is | |
3262 | * dynamically sized based on the maximum CPU number this system | |
3263 | * can have, taking hotplug into account (nr_cpu_ids). | |
3264 | */ | |
af7f588d | 3265 | mm_size = sizeof(struct mm_struct) + cpumask_size() + mm_cid_size(); |
af806027 PZ |
3266 | |
3267 | mm_cachep = kmem_cache_create_usercopy("mm_struct", | |
3268 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN, | |
3269 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, | |
3270 | offsetof(struct mm_struct, saved_auxv), | |
3271 | sizeof_field(struct mm_struct, saved_auxv), | |
3272 | NULL); | |
3273 | } | |
3274 | ||
3275 | void __init proc_caches_init(void) | |
3276 | { | |
1da177e4 LT |
3277 | sighand_cachep = kmem_cache_create("sighand_cache", |
3278 | sizeof(struct sighand_struct), 0, | |
5f0d5a3a | 3279 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| |
75f296d9 | 3280 | SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
3281 | signal_cachep = kmem_cache_create("signal_cache", |
3282 | sizeof(struct signal_struct), 0, | |
75f296d9 | 3283 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3284 | NULL); |
20c2df83 | 3285 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 3286 | sizeof(struct files_struct), 0, |
75f296d9 | 3287 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3288 | NULL); |
20c2df83 | 3289 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 3290 | sizeof(struct fs_struct), 0, |
75f296d9 | 3291 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3292 | NULL); |
c1a2f7f0 | 3293 | |
5d097056 | 3294 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); |
c7f8f31c SB |
3295 | #ifdef CONFIG_PER_VMA_LOCK |
3296 | vma_lock_cachep = KMEM_CACHE(vma_lock, SLAB_PANIC|SLAB_ACCOUNT); | |
3297 | #endif | |
8feae131 | 3298 | mmap_init(); |
66577193 | 3299 | nsproxy_cache_init(); |
1da177e4 | 3300 | } |
cf2e340f | 3301 | |
cf2e340f | 3302 | /* |
9bfb23fc | 3303 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 3304 | */ |
9bfb23fc | 3305 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 3306 | { |
9bfb23fc ON |
3307 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
3308 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 3309 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
769071ac AV |
3310 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP| |
3311 | CLONE_NEWTIME)) | |
9bfb23fc | 3312 | return -EINVAL; |
cf2e340f | 3313 | /* |
12c641ab EB |
3314 | * Not implemented, but pretend it works if there is nothing |
3315 | * to unshare. Note that unsharing the address space or the | |
3316 | * signal handlers also need to unshare the signal queues (aka | |
3317 | * CLONE_THREAD). | |
cf2e340f | 3318 | */ |
9bfb23fc | 3319 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
3320 | if (!thread_group_empty(current)) |
3321 | return -EINVAL; | |
3322 | } | |
3323 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
d036bda7 | 3324 | if (refcount_read(¤t->sighand->count) > 1) |
12c641ab EB |
3325 | return -EINVAL; |
3326 | } | |
3327 | if (unshare_flags & CLONE_VM) { | |
3328 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
3329 | return -EINVAL; |
3330 | } | |
cf2e340f JD |
3331 | |
3332 | return 0; | |
3333 | } | |
3334 | ||
3335 | /* | |
99d1419d | 3336 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
3337 | */ |
3338 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
3339 | { | |
3340 | struct fs_struct *fs = current->fs; | |
3341 | ||
498052bb AV |
3342 | if (!(unshare_flags & CLONE_FS) || !fs) |
3343 | return 0; | |
3344 | ||
3345 | /* don't need lock here; in the worst case we'll do useless copy */ | |
3346 | if (fs->users == 1) | |
3347 | return 0; | |
3348 | ||
3349 | *new_fsp = copy_fs_struct(fs); | |
3350 | if (!*new_fsp) | |
3351 | return -ENOMEM; | |
cf2e340f JD |
3352 | |
3353 | return 0; | |
3354 | } | |
3355 | ||
cf2e340f | 3356 | /* |
a016f338 | 3357 | * Unshare file descriptor table if it is being shared |
cf2e340f | 3358 | */ |
60997c3d CB |
3359 | int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
3360 | struct files_struct **new_fdp) | |
cf2e340f JD |
3361 | { |
3362 | struct files_struct *fd = current->files; | |
a016f338 | 3363 | int error = 0; |
cf2e340f JD |
3364 | |
3365 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 | 3366 | (fd && atomic_read(&fd->count) > 1)) { |
60997c3d | 3367 | *new_fdp = dup_fd(fd, max_fds, &error); |
a016f338 JD |
3368 | if (!*new_fdp) |
3369 | return error; | |
3370 | } | |
cf2e340f JD |
3371 | |
3372 | return 0; | |
3373 | } | |
3374 | ||
cf2e340f JD |
3375 | /* |
3376 | * unshare allows a process to 'unshare' part of the process | |
3377 | * context which was originally shared using clone. copy_* | |
cad6967a | 3378 | * functions used by kernel_clone() cannot be used here directly |
cf2e340f JD |
3379 | * because they modify an inactive task_struct that is being |
3380 | * constructed. Here we are modifying the current, active, | |
3381 | * task_struct. | |
3382 | */ | |
9b32105e | 3383 | int ksys_unshare(unsigned long unshare_flags) |
cf2e340f | 3384 | { |
cf2e340f | 3385 | struct fs_struct *fs, *new_fs = NULL; |
ba1f70dd | 3386 | struct files_struct *new_fd = NULL; |
b2e0d987 | 3387 | struct cred *new_cred = NULL; |
cf7b708c | 3388 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 3389 | int do_sysvsem = 0; |
9bfb23fc | 3390 | int err; |
cf2e340f | 3391 | |
b2e0d987 | 3392 | /* |
faf00da5 EB |
3393 | * If unsharing a user namespace must also unshare the thread group |
3394 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
3395 | */ |
3396 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 3397 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
3398 | /* |
3399 | * If unsharing vm, must also unshare signal handlers. | |
3400 | */ | |
3401 | if (unshare_flags & CLONE_VM) | |
3402 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
3403 | /* |
3404 | * If unsharing a signal handlers, must also unshare the signal queues. | |
3405 | */ | |
3406 | if (unshare_flags & CLONE_SIGHAND) | |
3407 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
3408 | /* |
3409 | * If unsharing namespace, must also unshare filesystem information. | |
3410 | */ | |
3411 | if (unshare_flags & CLONE_NEWNS) | |
3412 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
3413 | |
3414 | err = check_unshare_flags(unshare_flags); | |
3415 | if (err) | |
3416 | goto bad_unshare_out; | |
6013f67f MS |
3417 | /* |
3418 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
3419 | * to a new ipc namespace, the semaphore arrays from the old | |
3420 | * namespace are unreachable. | |
3421 | */ | |
3422 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 3423 | do_sysvsem = 1; |
fb0a685c DRO |
3424 | err = unshare_fs(unshare_flags, &new_fs); |
3425 | if (err) | |
9bfb23fc | 3426 | goto bad_unshare_out; |
60997c3d | 3427 | err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd); |
fb0a685c | 3428 | if (err) |
9bfb23fc | 3429 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 3430 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 3431 | if (err) |
9edff4ab | 3432 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
3433 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
3434 | new_cred, new_fs); | |
3435 | if (err) | |
3436 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 3437 | |
905ae01c AG |
3438 | if (new_cred) { |
3439 | err = set_cred_ucounts(new_cred); | |
3440 | if (err) | |
3441 | goto bad_unshare_cleanup_cred; | |
3442 | } | |
3443 | ||
b2e0d987 | 3444 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
3445 | if (do_sysvsem) { |
3446 | /* | |
3447 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
3448 | */ | |
3449 | exit_sem(current); | |
3450 | } | |
ab602f79 JM |
3451 | if (unshare_flags & CLONE_NEWIPC) { |
3452 | /* Orphan segments in old ns (see sem above). */ | |
3453 | exit_shm(current); | |
3454 | shm_init_task(current); | |
3455 | } | |
ab516013 | 3456 | |
6f977e6b | 3457 | if (new_nsproxy) |
cf7b708c | 3458 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 3459 | |
cf7b708c PE |
3460 | task_lock(current); |
3461 | ||
cf2e340f JD |
3462 | if (new_fs) { |
3463 | fs = current->fs; | |
2a4419b5 | 3464 | spin_lock(&fs->lock); |
cf2e340f | 3465 | current->fs = new_fs; |
498052bb AV |
3466 | if (--fs->users) |
3467 | new_fs = NULL; | |
3468 | else | |
3469 | new_fs = fs; | |
2a4419b5 | 3470 | spin_unlock(&fs->lock); |
cf2e340f JD |
3471 | } |
3472 | ||
ba1f70dd RX |
3473 | if (new_fd) |
3474 | swap(current->files, new_fd); | |
cf2e340f JD |
3475 | |
3476 | task_unlock(current); | |
b2e0d987 EB |
3477 | |
3478 | if (new_cred) { | |
3479 | /* Install the new user namespace */ | |
3480 | commit_creds(new_cred); | |
3481 | new_cred = NULL; | |
3482 | } | |
cf2e340f JD |
3483 | } |
3484 | ||
e4222673 HB |
3485 | perf_event_namespaces(current); |
3486 | ||
b2e0d987 EB |
3487 | bad_unshare_cleanup_cred: |
3488 | if (new_cred) | |
3489 | put_cred(new_cred); | |
cf2e340f JD |
3490 | bad_unshare_cleanup_fd: |
3491 | if (new_fd) | |
3492 | put_files_struct(new_fd); | |
3493 | ||
cf2e340f JD |
3494 | bad_unshare_cleanup_fs: |
3495 | if (new_fs) | |
498052bb | 3496 | free_fs_struct(new_fs); |
cf2e340f | 3497 | |
cf2e340f JD |
3498 | bad_unshare_out: |
3499 | return err; | |
3500 | } | |
3b125388 | 3501 | |
9b32105e DB |
3502 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
3503 | { | |
3504 | return ksys_unshare(unshare_flags); | |
3505 | } | |
3506 | ||
3b125388 AV |
3507 | /* |
3508 | * Helper to unshare the files of the current task. | |
3509 | * We don't want to expose copy_files internals to | |
3510 | * the exec layer of the kernel. | |
3511 | */ | |
3512 | ||
1f702603 | 3513 | int unshare_files(void) |
3b125388 AV |
3514 | { |
3515 | struct task_struct *task = current; | |
1f702603 | 3516 | struct files_struct *old, *copy = NULL; |
3b125388 AV |
3517 | int error; |
3518 | ||
60997c3d | 3519 | error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); |
1f702603 | 3520 | if (error || !copy) |
3b125388 | 3521 | return error; |
1f702603 EB |
3522 | |
3523 | old = task->files; | |
3b125388 AV |
3524 | task_lock(task); |
3525 | task->files = copy; | |
3526 | task_unlock(task); | |
1f702603 | 3527 | put_files_struct(old); |
3b125388 AV |
3528 | return 0; |
3529 | } | |
16db3d3f HS |
3530 | |
3531 | int sysctl_max_threads(struct ctl_table *table, int write, | |
b0daa2c7 | 3532 | void *buffer, size_t *lenp, loff_t *ppos) |
16db3d3f HS |
3533 | { |
3534 | struct ctl_table t; | |
3535 | int ret; | |
3536 | int threads = max_threads; | |
b0f53dbc | 3537 | int min = 1; |
16db3d3f HS |
3538 | int max = MAX_THREADS; |
3539 | ||
3540 | t = *table; | |
3541 | t.data = &threads; | |
3542 | t.extra1 = &min; | |
3543 | t.extra2 = &max; | |
3544 | ||
3545 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
3546 | if (ret || !write) | |
3547 | return ret; | |
3548 | ||
b0f53dbc | 3549 | max_threads = threads; |
16db3d3f HS |
3550 | |
3551 | return 0; | |
3552 | } |