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 LT |
39 | #include <linux/key.h> |
40 | #include <linux/binfmts.h> | |
41 | #include <linux/mman.h> | |
cddb8a5c | 42 | #include <linux/mmu_notifier.h> |
1da177e4 | 43 | #include <linux/fs.h> |
615d6e87 | 44 | #include <linux/mm.h> |
17fca131 | 45 | #include <linux/mm_inline.h> |
615d6e87 | 46 | #include <linux/vmacache.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> |
0a425405 | 78 | #include <linux/random.h> |
522ed776 | 79 | #include <linux/tty.h> |
5ad4e53b | 80 | #include <linux/fs_struct.h> |
7c9f8861 | 81 | #include <linux/magic.h> |
cdd6c482 | 82 | #include <linux/perf_event.h> |
42c4ab41 | 83 | #include <linux/posix-timers.h> |
8e7cac79 | 84 | #include <linux/user-return-notifier.h> |
3d5992d2 | 85 | #include <linux/oom.h> |
ba76149f | 86 | #include <linux/khugepaged.h> |
d80e731e | 87 | #include <linux/signalfd.h> |
0326f5a9 | 88 | #include <linux/uprobes.h> |
a27bb332 | 89 | #include <linux/aio.h> |
52f5684c | 90 | #include <linux/compiler.h> |
16db3d3f | 91 | #include <linux/sysctl.h> |
5c9a8750 | 92 | #include <linux/kcov.h> |
d83a7cb3 | 93 | #include <linux/livepatch.h> |
48ac3c18 | 94 | #include <linux/thread_info.h> |
afaef01c | 95 | #include <linux/stackleak.h> |
eafb149e | 96 | #include <linux/kasan.h> |
d08b9f0c | 97 | #include <linux/scs.h> |
0f212204 | 98 | #include <linux/io_uring.h> |
a10787e6 | 99 | #include <linux/bpf.h> |
a6cbd440 | 100 | #include <linux/sched/mm.h> |
1da177e4 | 101 | |
1da177e4 | 102 | #include <asm/pgalloc.h> |
7c0f6ba6 | 103 | #include <linux/uaccess.h> |
1da177e4 LT |
104 | #include <asm/mmu_context.h> |
105 | #include <asm/cacheflush.h> | |
106 | #include <asm/tlbflush.h> | |
107 | ||
ad8d75ff SR |
108 | #include <trace/events/sched.h> |
109 | ||
43d2b113 KH |
110 | #define CREATE_TRACE_POINTS |
111 | #include <trace/events/task.h> | |
112 | ||
ac1b398d HS |
113 | /* |
114 | * Minimum number of threads to boot the kernel | |
115 | */ | |
116 | #define MIN_THREADS 20 | |
117 | ||
118 | /* | |
119 | * Maximum number of threads | |
120 | */ | |
121 | #define MAX_THREADS FUTEX_TID_MASK | |
122 | ||
1da177e4 LT |
123 | /* |
124 | * Protected counters by write_lock_irq(&tasklist_lock) | |
125 | */ | |
126 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 127 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 | 128 | |
8856ae4d | 129 | static int max_threads; /* tunable limit on nr_threads */ |
1da177e4 | 130 | |
8495f7e6 SPP |
131 | #define NAMED_ARRAY_INDEX(x) [x] = __stringify(x) |
132 | ||
133 | static const char * const resident_page_types[] = { | |
134 | NAMED_ARRAY_INDEX(MM_FILEPAGES), | |
135 | NAMED_ARRAY_INDEX(MM_ANONPAGES), | |
136 | NAMED_ARRAY_INDEX(MM_SWAPENTS), | |
137 | NAMED_ARRAY_INDEX(MM_SHMEMPAGES), | |
138 | }; | |
139 | ||
1da177e4 LT |
140 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; |
141 | ||
c59923a1 | 142 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
143 | |
144 | #ifdef CONFIG_PROVE_RCU | |
145 | int lockdep_tasklist_lock_is_held(void) | |
146 | { | |
147 | return lockdep_is_held(&tasklist_lock); | |
148 | } | |
149 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
150 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
151 | |
152 | int nr_processes(void) | |
153 | { | |
154 | int cpu; | |
155 | int total = 0; | |
156 | ||
1d510750 | 157 | for_each_possible_cpu(cpu) |
1da177e4 LT |
158 | total += per_cpu(process_counts, cpu); |
159 | ||
160 | return total; | |
161 | } | |
162 | ||
f19b9f74 AM |
163 | void __weak arch_release_task_struct(struct task_struct *tsk) |
164 | { | |
165 | } | |
166 | ||
f5e10287 | 167 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 168 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
169 | |
170 | static inline struct task_struct *alloc_task_struct_node(int node) | |
171 | { | |
172 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
173 | } | |
174 | ||
41101809 TG |
175 | static inline void free_task_struct(struct task_struct *tsk) |
176 | { | |
41101809 TG |
177 | kmem_cache_free(task_struct_cachep, tsk); |
178 | } | |
1da177e4 LT |
179 | #endif |
180 | ||
b235beea | 181 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 182 | |
0d15d74a TG |
183 | /* |
184 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
185 | * kmemcache based allocator. | |
186 | */ | |
ba14a194 | 187 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) |
ac496bf4 | 188 | |
be9a2277 | 189 | # ifdef CONFIG_VMAP_STACK |
ac496bf4 AL |
190 | /* |
191 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB | |
192 | * flush. Try to minimize the number of calls by caching stacks. | |
193 | */ | |
194 | #define NR_CACHED_STACKS 2 | |
195 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); | |
19659c59 | 196 | |
e540bf31 SAS |
197 | struct vm_stack { |
198 | struct rcu_head rcu; | |
199 | struct vm_struct *stack_vm_area; | |
200 | }; | |
201 | ||
202 | static bool try_release_thread_stack_to_cache(struct vm_struct *vm) | |
203 | { | |
204 | unsigned int i; | |
205 | ||
206 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
207 | if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL) | |
208 | continue; | |
209 | return true; | |
210 | } | |
211 | return false; | |
212 | } | |
213 | ||
214 | static void thread_stack_free_rcu(struct rcu_head *rh) | |
215 | { | |
216 | struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu); | |
217 | ||
218 | if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area)) | |
219 | return; | |
220 | ||
221 | vfree(vm_stack); | |
222 | } | |
223 | ||
224 | static void thread_stack_delayed_free(struct task_struct *tsk) | |
225 | { | |
226 | struct vm_stack *vm_stack = tsk->stack; | |
227 | ||
228 | vm_stack->stack_vm_area = tsk->stack_vm_area; | |
229 | call_rcu(&vm_stack->rcu, thread_stack_free_rcu); | |
230 | } | |
231 | ||
19659c59 HR |
232 | static int free_vm_stack_cache(unsigned int cpu) |
233 | { | |
234 | struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); | |
235 | int i; | |
236 | ||
237 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
238 | struct vm_struct *vm_stack = cached_vm_stacks[i]; | |
239 | ||
240 | if (!vm_stack) | |
241 | continue; | |
242 | ||
243 | vfree(vm_stack->addr); | |
244 | cached_vm_stacks[i] = NULL; | |
245 | } | |
246 | ||
247 | return 0; | |
248 | } | |
ac496bf4 | 249 | |
1a03d3f1 | 250 | static int memcg_charge_kernel_stack(struct vm_struct *vm) |
b69c49b7 | 251 | { |
f1c1a9ee SAS |
252 | int i; |
253 | int ret; | |
254 | ||
255 | BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); | |
256 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); | |
257 | ||
258 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { | |
259 | ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0); | |
260 | if (ret) | |
261 | goto err; | |
262 | } | |
263 | return 0; | |
264 | err: | |
265 | /* | |
266 | * If memcg_kmem_charge_page() fails, page's memory cgroup pointer is | |
267 | * NULL, and memcg_kmem_uncharge_page() in free_thread_stack() will | |
268 | * ignore this page. | |
269 | */ | |
270 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) | |
271 | memcg_kmem_uncharge_page(vm->pages[i], 0); | |
272 | return ret; | |
273 | } | |
274 | ||
7865aba3 | 275 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
b69c49b7 | 276 | { |
1a03d3f1 | 277 | struct vm_struct *vm; |
ac496bf4 AL |
278 | void *stack; |
279 | int i; | |
280 | ||
ac496bf4 | 281 | for (i = 0; i < NR_CACHED_STACKS; i++) { |
112166f8 CL |
282 | struct vm_struct *s; |
283 | ||
284 | s = this_cpu_xchg(cached_stacks[i], NULL); | |
ac496bf4 AL |
285 | |
286 | if (!s) | |
287 | continue; | |
ac496bf4 | 288 | |
51fb34de | 289 | /* Reset stack metadata. */ |
cebd0eb2 | 290 | kasan_unpoison_range(s->addr, THREAD_SIZE); |
eafb149e | 291 | |
51fb34de AK |
292 | stack = kasan_reset_tag(s->addr); |
293 | ||
ca182551 | 294 | /* Clear stale pointers from reused stack. */ |
51fb34de | 295 | memset(stack, 0, THREAD_SIZE); |
e01e8063 | 296 | |
1a03d3f1 | 297 | if (memcg_charge_kernel_stack(s)) { |
f1c1a9ee SAS |
298 | vfree(s->addr); |
299 | return -ENOMEM; | |
300 | } | |
301 | ||
ac496bf4 | 302 | tsk->stack_vm_area = s; |
51fb34de | 303 | tsk->stack = stack; |
7865aba3 | 304 | return 0; |
ac496bf4 | 305 | } |
ac496bf4 | 306 | |
9b6f7e16 RG |
307 | /* |
308 | * Allocated stacks are cached and later reused by new threads, | |
309 | * so memcg accounting is performed manually on assigning/releasing | |
310 | * stacks to tasks. Drop __GFP_ACCOUNT. | |
311 | */ | |
48ac3c18 | 312 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, |
ac496bf4 | 313 | VMALLOC_START, VMALLOC_END, |
9b6f7e16 | 314 | THREADINFO_GFP & ~__GFP_ACCOUNT, |
ac496bf4 AL |
315 | PAGE_KERNEL, |
316 | 0, node, __builtin_return_address(0)); | |
7865aba3 SAS |
317 | if (!stack) |
318 | return -ENOMEM; | |
ba14a194 | 319 | |
1a03d3f1 SAS |
320 | vm = find_vm_area(stack); |
321 | if (memcg_charge_kernel_stack(vm)) { | |
f1c1a9ee SAS |
322 | vfree(stack); |
323 | return -ENOMEM; | |
324 | } | |
ba14a194 AL |
325 | /* |
326 | * We can't call find_vm_area() in interrupt context, and | |
327 | * free_thread_stack() can be called in interrupt context, | |
328 | * so cache the vm_struct. | |
329 | */ | |
1a03d3f1 | 330 | tsk->stack_vm_area = vm; |
51fb34de | 331 | stack = kasan_reset_tag(stack); |
7865aba3 SAS |
332 | tsk->stack = stack; |
333 | return 0; | |
b69c49b7 FT |
334 | } |
335 | ||
be9a2277 | 336 | static void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 337 | { |
e540bf31 SAS |
338 | if (!try_release_thread_stack_to_cache(tsk->stack_vm_area)) |
339 | thread_stack_delayed_free(tsk); | |
9b6f7e16 | 340 | |
be9a2277 SAS |
341 | tsk->stack = NULL; |
342 | tsk->stack_vm_area = NULL; | |
343 | } | |
ac496bf4 | 344 | |
be9a2277 | 345 | # else /* !CONFIG_VMAP_STACK */ |
ac496bf4 | 346 | |
e540bf31 SAS |
347 | static void thread_stack_free_rcu(struct rcu_head *rh) |
348 | { | |
349 | __free_pages(virt_to_page(rh), THREAD_SIZE_ORDER); | |
350 | } | |
351 | ||
352 | static void thread_stack_delayed_free(struct task_struct *tsk) | |
353 | { | |
354 | struct rcu_head *rh = tsk->stack; | |
355 | ||
356 | call_rcu(rh, thread_stack_free_rcu); | |
357 | } | |
358 | ||
7865aba3 | 359 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
be9a2277 | 360 | { |
4949148a VD |
361 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
362 | THREAD_SIZE_ORDER); | |
b6a84016 | 363 | |
1bf4580e | 364 | if (likely(page)) { |
8dcc1d34 | 365 | tsk->stack = kasan_reset_tag(page_address(page)); |
7865aba3 | 366 | return 0; |
1bf4580e | 367 | } |
7865aba3 | 368 | return -ENOMEM; |
b69c49b7 FT |
369 | } |
370 | ||
be9a2277 | 371 | static void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 372 | { |
e540bf31 | 373 | thread_stack_delayed_free(tsk); |
be9a2277 | 374 | tsk->stack = NULL; |
b69c49b7 | 375 | } |
ac496bf4 | 376 | |
be9a2277 SAS |
377 | # endif /* CONFIG_VMAP_STACK */ |
378 | # else /* !(THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)) */ | |
9b6f7e16 | 379 | |
b235beea | 380 | static struct kmem_cache *thread_stack_cache; |
ac496bf4 | 381 | |
e540bf31 SAS |
382 | static void thread_stack_free_rcu(struct rcu_head *rh) |
383 | { | |
384 | kmem_cache_free(thread_stack_cache, rh); | |
385 | } | |
ac496bf4 | 386 | |
e540bf31 SAS |
387 | static void thread_stack_delayed_free(struct task_struct *tsk) |
388 | { | |
389 | struct rcu_head *rh = tsk->stack; | |
ac496bf4 | 390 | |
e540bf31 | 391 | call_rcu(rh, thread_stack_free_rcu); |
b69c49b7 | 392 | } |
0d15d74a | 393 | |
7865aba3 | 394 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
0d15d74a | 395 | { |
5eed6f1d RR |
396 | unsigned long *stack; |
397 | stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); | |
8dcc1d34 | 398 | stack = kasan_reset_tag(stack); |
5eed6f1d | 399 | tsk->stack = stack; |
7865aba3 | 400 | return stack ? 0 : -ENOMEM; |
0d15d74a TG |
401 | } |
402 | ||
ba14a194 | 403 | static void free_thread_stack(struct task_struct *tsk) |
0d15d74a | 404 | { |
e540bf31 | 405 | thread_stack_delayed_free(tsk); |
be9a2277 | 406 | tsk->stack = NULL; |
0d15d74a TG |
407 | } |
408 | ||
b235beea | 409 | void thread_stack_cache_init(void) |
0d15d74a | 410 | { |
f9d29946 DW |
411 | thread_stack_cache = kmem_cache_create_usercopy("thread_stack", |
412 | THREAD_SIZE, THREAD_SIZE, 0, 0, | |
413 | THREAD_SIZE, NULL); | |
b235beea | 414 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a | 415 | } |
be9a2277 SAS |
416 | |
417 | # endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */ | |
2bb0529c SAS |
418 | #else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */ |
419 | ||
7865aba3 | 420 | static int alloc_thread_stack_node(struct task_struct *tsk, int node) |
2bb0529c SAS |
421 | { |
422 | unsigned long *stack; | |
423 | ||
424 | stack = arch_alloc_thread_stack_node(tsk, node); | |
425 | tsk->stack = stack; | |
7865aba3 | 426 | return stack ? 0 : -ENOMEM; |
2bb0529c SAS |
427 | } |
428 | ||
429 | static void free_thread_stack(struct task_struct *tsk) | |
430 | { | |
431 | arch_free_thread_stack(tsk); | |
432 | tsk->stack = NULL; | |
433 | } | |
434 | ||
be9a2277 | 435 | #endif /* !CONFIG_ARCH_THREAD_STACK_ALLOCATOR */ |
b69c49b7 | 436 | |
1da177e4 | 437 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 438 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
439 | |
440 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 441 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
442 | |
443 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 444 | struct kmem_cache *files_cachep; |
1da177e4 LT |
445 | |
446 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 447 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
448 | |
449 | /* SLAB cache for vm_area_struct structures */ | |
3928d4f5 | 450 | static struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
451 | |
452 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 453 | static struct kmem_cache *mm_cachep; |
1da177e4 | 454 | |
490fc053 | 455 | struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) |
3928d4f5 | 456 | { |
a670468f | 457 | struct vm_area_struct *vma; |
490fc053 | 458 | |
a670468f | 459 | vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
027232da KS |
460 | if (vma) |
461 | vma_init(vma, mm); | |
490fc053 | 462 | return vma; |
3928d4f5 LT |
463 | } |
464 | ||
465 | struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) | |
466 | { | |
95faf699 LT |
467 | struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
468 | ||
469 | if (new) { | |
cda099b3 QC |
470 | ASSERT_EXCLUSIVE_WRITER(orig->vm_flags); |
471 | ASSERT_EXCLUSIVE_WRITER(orig->vm_file); | |
472 | /* | |
473 | * orig->shared.rb may be modified concurrently, but the clone | |
474 | * will be reinitialized. | |
475 | */ | |
476 | *new = data_race(*orig); | |
95faf699 | 477 | INIT_LIST_HEAD(&new->anon_vma_chain); |
e39a4b33 | 478 | new->vm_next = new->vm_prev = NULL; |
5c26f6ac | 479 | dup_anon_vma_name(orig, new); |
95faf699 LT |
480 | } |
481 | return new; | |
3928d4f5 LT |
482 | } |
483 | ||
484 | void vm_area_free(struct vm_area_struct *vma) | |
485 | { | |
5c26f6ac | 486 | free_anon_vma_name(vma); |
3928d4f5 LT |
487 | kmem_cache_free(vm_area_cachep, vma); |
488 | } | |
489 | ||
ba14a194 | 490 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 491 | { |
0ce055f8 SAS |
492 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
493 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
27faca83 | 494 | int i; |
ba14a194 | 495 | |
27faca83 MS |
496 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) |
497 | mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB, | |
498 | account * (PAGE_SIZE / 1024)); | |
499 | } else { | |
0ce055f8 SAS |
500 | void *stack = task_stack_page(tsk); |
501 | ||
27faca83 | 502 | /* All stack pages are in the same node. */ |
da3ceeff | 503 | mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB, |
991e7673 | 504 | account * (THREAD_SIZE / 1024)); |
27faca83 | 505 | } |
c6a7f572 KM |
506 | } |
507 | ||
1a03d3f1 | 508 | void exit_task_stack_account(struct task_struct *tsk) |
9b6f7e16 | 509 | { |
1a03d3f1 | 510 | account_kernel_stack(tsk, -1); |
991e7673 | 511 | |
1a03d3f1 SAS |
512 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
513 | struct vm_struct *vm; | |
9b6f7e16 RG |
514 | int i; |
515 | ||
1a03d3f1 SAS |
516 | vm = task_stack_vm_area(tsk); |
517 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) | |
518 | memcg_kmem_uncharge_page(vm->pages[i], 0); | |
9b6f7e16 | 519 | } |
9b6f7e16 RG |
520 | } |
521 | ||
68f24b08 | 522 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 523 | { |
2f064a59 | 524 | if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD)) |
405c0759 AL |
525 | return; /* Better to leak the stack than to free prematurely */ |
526 | ||
ba14a194 | 527 | free_thread_stack(tsk); |
68f24b08 AL |
528 | } |
529 | ||
530 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
531 | void put_task_stack(struct task_struct *tsk) | |
532 | { | |
f0b89d39 | 533 | if (refcount_dec_and_test(&tsk->stack_refcount)) |
68f24b08 AL |
534 | release_task_stack(tsk); |
535 | } | |
536 | #endif | |
537 | ||
538 | void free_task(struct task_struct *tsk) | |
539 | { | |
b90ca8ba | 540 | release_user_cpus_ptr(tsk); |
d08b9f0c ST |
541 | scs_release(tsk); |
542 | ||
68f24b08 AL |
543 | #ifndef CONFIG_THREAD_INFO_IN_TASK |
544 | /* | |
545 | * The task is finally done with both the stack and thread_info, | |
546 | * so free both. | |
547 | */ | |
548 | release_task_stack(tsk); | |
549 | #else | |
550 | /* | |
551 | * If the task had a separate stack allocation, it should be gone | |
552 | * by now. | |
553 | */ | |
f0b89d39 | 554 | WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0); |
68f24b08 | 555 | #endif |
23f78d4a | 556 | rt_mutex_debug_task_free(tsk); |
fb52607a | 557 | ftrace_graph_exit_task(tsk); |
f19b9f74 | 558 | arch_release_task_struct(tsk); |
1da5c46f ON |
559 | if (tsk->flags & PF_KTHREAD) |
560 | free_kthread_struct(tsk); | |
1da177e4 LT |
561 | free_task_struct(tsk); |
562 | } | |
563 | EXPORT_SYMBOL(free_task); | |
564 | ||
fe69d560 DH |
565 | static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm) |
566 | { | |
567 | struct file *exe_file; | |
568 | ||
569 | exe_file = get_mm_exe_file(oldmm); | |
570 | RCU_INIT_POINTER(mm->exe_file, exe_file); | |
571 | /* | |
572 | * We depend on the oldmm having properly denied write access to the | |
573 | * exe_file already. | |
574 | */ | |
575 | if (exe_file && deny_write_access(exe_file)) | |
576 | pr_warn_once("deny_write_access() failed in %s\n", __func__); | |
577 | } | |
578 | ||
d70f2a14 AM |
579 | #ifdef CONFIG_MMU |
580 | static __latent_entropy int dup_mmap(struct mm_struct *mm, | |
581 | struct mm_struct *oldmm) | |
582 | { | |
583 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; | |
584 | struct rb_node **rb_link, *rb_parent; | |
585 | int retval; | |
586 | unsigned long charge; | |
587 | LIST_HEAD(uf); | |
588 | ||
589 | uprobe_start_dup_mmap(); | |
d8ed45c5 | 590 | if (mmap_write_lock_killable(oldmm)) { |
d70f2a14 AM |
591 | retval = -EINTR; |
592 | goto fail_uprobe_end; | |
593 | } | |
594 | flush_cache_dup_mm(oldmm); | |
595 | uprobe_dup_mmap(oldmm, mm); | |
596 | /* | |
597 | * Not linked in yet - no deadlock potential: | |
598 | */ | |
aaa2cc56 | 599 | mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING); |
d70f2a14 AM |
600 | |
601 | /* No ordering required: file already has been exposed. */ | |
fe69d560 | 602 | dup_mm_exe_file(mm, oldmm); |
d70f2a14 AM |
603 | |
604 | mm->total_vm = oldmm->total_vm; | |
605 | mm->data_vm = oldmm->data_vm; | |
606 | mm->exec_vm = oldmm->exec_vm; | |
607 | mm->stack_vm = oldmm->stack_vm; | |
608 | ||
609 | rb_link = &mm->mm_rb.rb_node; | |
610 | rb_parent = NULL; | |
611 | pprev = &mm->mmap; | |
612 | retval = ksm_fork(mm, oldmm); | |
613 | if (retval) | |
614 | goto out; | |
615 | retval = khugepaged_fork(mm, oldmm); | |
616 | if (retval) | |
617 | goto out; | |
618 | ||
619 | prev = NULL; | |
620 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { | |
621 | struct file *file; | |
622 | ||
623 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
624 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); | |
625 | continue; | |
626 | } | |
627 | charge = 0; | |
655c79bb TH |
628 | /* |
629 | * Don't duplicate many vmas if we've been oom-killed (for | |
630 | * example) | |
631 | */ | |
632 | if (fatal_signal_pending(current)) { | |
633 | retval = -EINTR; | |
634 | goto out; | |
635 | } | |
d70f2a14 AM |
636 | if (mpnt->vm_flags & VM_ACCOUNT) { |
637 | unsigned long len = vma_pages(mpnt); | |
638 | ||
639 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ | |
640 | goto fail_nomem; | |
641 | charge = len; | |
642 | } | |
3928d4f5 | 643 | tmp = vm_area_dup(mpnt); |
d70f2a14 AM |
644 | if (!tmp) |
645 | goto fail_nomem; | |
d70f2a14 AM |
646 | retval = vma_dup_policy(mpnt, tmp); |
647 | if (retval) | |
648 | goto fail_nomem_policy; | |
649 | tmp->vm_mm = mm; | |
650 | retval = dup_userfaultfd(tmp, &uf); | |
651 | if (retval) | |
652 | goto fail_nomem_anon_vma_fork; | |
653 | if (tmp->vm_flags & VM_WIPEONFORK) { | |
93949bb2 LX |
654 | /* |
655 | * VM_WIPEONFORK gets a clean slate in the child. | |
656 | * Don't prepare anon_vma until fault since we don't | |
657 | * copy page for current vma. | |
658 | */ | |
d70f2a14 | 659 | tmp->anon_vma = NULL; |
d70f2a14 AM |
660 | } else if (anon_vma_fork(tmp, mpnt)) |
661 | goto fail_nomem_anon_vma_fork; | |
662 | tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); | |
d70f2a14 AM |
663 | file = tmp->vm_file; |
664 | if (file) { | |
d70f2a14 AM |
665 | struct address_space *mapping = file->f_mapping; |
666 | ||
667 | get_file(file); | |
d70f2a14 AM |
668 | i_mmap_lock_write(mapping); |
669 | if (tmp->vm_flags & VM_SHARED) | |
cf508b58 | 670 | mapping_allow_writable(mapping); |
d70f2a14 AM |
671 | flush_dcache_mmap_lock(mapping); |
672 | /* insert tmp into the share list, just after mpnt */ | |
673 | vma_interval_tree_insert_after(tmp, mpnt, | |
674 | &mapping->i_mmap); | |
675 | flush_dcache_mmap_unlock(mapping); | |
676 | i_mmap_unlock_write(mapping); | |
677 | } | |
678 | ||
679 | /* | |
680 | * Clear hugetlb-related page reserves for children. This only | |
681 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
682 | * are not guaranteed to succeed, even if read-only | |
683 | */ | |
684 | if (is_vm_hugetlb_page(tmp)) | |
685 | reset_vma_resv_huge_pages(tmp); | |
686 | ||
687 | /* | |
688 | * Link in the new vma and copy the page table entries. | |
689 | */ | |
690 | *pprev = tmp; | |
691 | pprev = &tmp->vm_next; | |
692 | tmp->vm_prev = prev; | |
693 | prev = tmp; | |
694 | ||
695 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
696 | rb_link = &tmp->vm_rb.rb_right; | |
697 | rb_parent = &tmp->vm_rb; | |
698 | ||
699 | mm->map_count++; | |
700 | if (!(tmp->vm_flags & VM_WIPEONFORK)) | |
c78f4636 | 701 | retval = copy_page_range(tmp, mpnt); |
d70f2a14 AM |
702 | |
703 | if (tmp->vm_ops && tmp->vm_ops->open) | |
704 | tmp->vm_ops->open(tmp); | |
705 | ||
706 | if (retval) | |
707 | goto out; | |
708 | } | |
709 | /* a new mm has just been created */ | |
1ed0cc5a | 710 | retval = arch_dup_mmap(oldmm, mm); |
d70f2a14 | 711 | out: |
d8ed45c5 | 712 | mmap_write_unlock(mm); |
d70f2a14 | 713 | flush_tlb_mm(oldmm); |
d8ed45c5 | 714 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
715 | dup_userfaultfd_complete(&uf); |
716 | fail_uprobe_end: | |
717 | uprobe_end_dup_mmap(); | |
718 | return retval; | |
719 | fail_nomem_anon_vma_fork: | |
720 | mpol_put(vma_policy(tmp)); | |
721 | fail_nomem_policy: | |
3928d4f5 | 722 | vm_area_free(tmp); |
d70f2a14 AM |
723 | fail_nomem: |
724 | retval = -ENOMEM; | |
725 | vm_unacct_memory(charge); | |
726 | goto out; | |
727 | } | |
728 | ||
729 | static inline int mm_alloc_pgd(struct mm_struct *mm) | |
730 | { | |
731 | mm->pgd = pgd_alloc(mm); | |
732 | if (unlikely(!mm->pgd)) | |
733 | return -ENOMEM; | |
734 | return 0; | |
735 | } | |
736 | ||
737 | static inline void mm_free_pgd(struct mm_struct *mm) | |
738 | { | |
739 | pgd_free(mm, mm->pgd); | |
740 | } | |
741 | #else | |
742 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) | |
743 | { | |
d8ed45c5 | 744 | mmap_write_lock(oldmm); |
fe69d560 | 745 | dup_mm_exe_file(mm, oldmm); |
d8ed45c5 | 746 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
747 | return 0; |
748 | } | |
749 | #define mm_alloc_pgd(mm) (0) | |
750 | #define mm_free_pgd(mm) | |
751 | #endif /* CONFIG_MMU */ | |
752 | ||
753 | static void check_mm(struct mm_struct *mm) | |
754 | { | |
755 | int i; | |
756 | ||
8495f7e6 SPP |
757 | BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS, |
758 | "Please make sure 'struct resident_page_types[]' is updated as well"); | |
759 | ||
d70f2a14 AM |
760 | for (i = 0; i < NR_MM_COUNTERS; i++) { |
761 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
762 | ||
763 | if (unlikely(x)) | |
8495f7e6 SPP |
764 | pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n", |
765 | mm, resident_page_types[i], x); | |
d70f2a14 AM |
766 | } |
767 | ||
768 | if (mm_pgtables_bytes(mm)) | |
769 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", | |
770 | mm_pgtables_bytes(mm)); | |
771 | ||
772 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
773 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); | |
774 | #endif | |
775 | } | |
776 | ||
777 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) | |
778 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
779 | ||
780 | /* | |
781 | * Called when the last reference to the mm | |
782 | * is dropped: either by a lazy thread or by | |
783 | * mmput. Free the page directory and the mm. | |
784 | */ | |
d34bc48f | 785 | void __mmdrop(struct mm_struct *mm) |
d70f2a14 AM |
786 | { |
787 | BUG_ON(mm == &init_mm); | |
3eda69c9 MR |
788 | WARN_ON_ONCE(mm == current->mm); |
789 | WARN_ON_ONCE(mm == current->active_mm); | |
d70f2a14 AM |
790 | mm_free_pgd(mm); |
791 | destroy_context(mm); | |
984cfe4e | 792 | mmu_notifier_subscriptions_destroy(mm); |
d70f2a14 AM |
793 | check_mm(mm); |
794 | put_user_ns(mm->user_ns); | |
795 | free_mm(mm); | |
796 | } | |
d34bc48f | 797 | EXPORT_SYMBOL_GPL(__mmdrop); |
d70f2a14 AM |
798 | |
799 | static void mmdrop_async_fn(struct work_struct *work) | |
800 | { | |
801 | struct mm_struct *mm; | |
802 | ||
803 | mm = container_of(work, struct mm_struct, async_put_work); | |
804 | __mmdrop(mm); | |
805 | } | |
806 | ||
807 | static void mmdrop_async(struct mm_struct *mm) | |
808 | { | |
809 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) { | |
810 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn); | |
811 | schedule_work(&mm->async_put_work); | |
812 | } | |
813 | } | |
814 | ||
ea6d290c ON |
815 | static inline void free_signal_struct(struct signal_struct *sig) |
816 | { | |
97101eb4 | 817 | taskstats_tgid_free(sig); |
1c5354de | 818 | sched_autogroup_exit(sig); |
7283094e MH |
819 | /* |
820 | * __mmdrop is not safe to call from softirq context on x86 due to | |
821 | * pgd_dtor so postpone it to the async context | |
822 | */ | |
26db62f1 | 823 | if (sig->oom_mm) |
7283094e | 824 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
825 | kmem_cache_free(signal_cachep, sig); |
826 | } | |
827 | ||
828 | static inline void put_signal_struct(struct signal_struct *sig) | |
829 | { | |
60d4de3f | 830 | if (refcount_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
831 | free_signal_struct(sig); |
832 | } | |
833 | ||
158d9ebd | 834 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 835 | { |
270f722d | 836 | WARN_ON(!tsk->exit_state); |
ec1d2819 | 837 | WARN_ON(refcount_read(&tsk->usage)); |
1da177e4 LT |
838 | WARN_ON(tsk == current); |
839 | ||
0f212204 | 840 | io_uring_free(tsk); |
2e91fa7f | 841 | cgroup_free(tsk); |
16d51a59 | 842 | task_numa_free(tsk, true); |
1a2a4d06 | 843 | security_task_free(tsk); |
a10787e6 | 844 | bpf_task_storage_free(tsk); |
e0e81739 | 845 | exit_creds(tsk); |
35df17c5 | 846 | delayacct_tsk_free(tsk); |
ea6d290c | 847 | put_signal_struct(tsk->signal); |
6e33cad0 | 848 | sched_core_free(tsk); |
2873cd31 | 849 | free_task(tsk); |
1da177e4 | 850 | } |
77c100c8 | 851 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 852 | |
6c0a9fa6 | 853 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 854 | |
ff691f6e HS |
855 | /* |
856 | * set_max_threads | |
857 | */ | |
16db3d3f | 858 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 859 | { |
ac1b398d | 860 | u64 threads; |
ca79b0c2 | 861 | unsigned long nr_pages = totalram_pages(); |
ff691f6e HS |
862 | |
863 | /* | |
ac1b398d HS |
864 | * The number of threads shall be limited such that the thread |
865 | * structures may only consume a small part of the available memory. | |
ff691f6e | 866 | */ |
3d6357de | 867 | if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64) |
ac1b398d HS |
868 | threads = MAX_THREADS; |
869 | else | |
3d6357de | 870 | threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE, |
ac1b398d HS |
871 | (u64) THREAD_SIZE * 8UL); |
872 | ||
16db3d3f HS |
873 | if (threads > max_threads_suggested) |
874 | threads = max_threads_suggested; | |
875 | ||
ac1b398d | 876 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
877 | } |
878 | ||
5aaeb5c0 IM |
879 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
880 | /* Initialized by the architecture: */ | |
881 | int arch_task_struct_size __read_mostly; | |
882 | #endif | |
0c8c0f03 | 883 | |
4189ff23 | 884 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
5905429a KC |
885 | static void task_struct_whitelist(unsigned long *offset, unsigned long *size) |
886 | { | |
887 | /* Fetch thread_struct whitelist for the architecture. */ | |
888 | arch_thread_struct_whitelist(offset, size); | |
889 | ||
890 | /* | |
891 | * Handle zero-sized whitelist or empty thread_struct, otherwise | |
892 | * adjust offset to position of thread_struct in task_struct. | |
893 | */ | |
894 | if (unlikely(*size == 0)) | |
895 | *offset = 0; | |
896 | else | |
897 | *offset += offsetof(struct task_struct, thread); | |
898 | } | |
4189ff23 | 899 | #endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */ |
5905429a | 900 | |
ff691f6e | 901 | void __init fork_init(void) |
1da177e4 | 902 | { |
25f9c081 | 903 | int i; |
f5e10287 | 904 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 905 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 906 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 907 | #endif |
95cb64c1 | 908 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
5905429a | 909 | unsigned long useroffset, usersize; |
e274795e | 910 | |
1da177e4 | 911 | /* create a slab on which task_structs can be allocated */ |
5905429a KC |
912 | task_struct_whitelist(&useroffset, &usersize); |
913 | task_struct_cachep = kmem_cache_create_usercopy("task_struct", | |
e274795e | 914 | arch_task_struct_size, align, |
5905429a KC |
915 | SLAB_PANIC|SLAB_ACCOUNT, |
916 | useroffset, usersize, NULL); | |
1da177e4 LT |
917 | #endif |
918 | ||
61c4628b SS |
919 | /* do the arch specific task caches init */ |
920 | arch_task_cache_init(); | |
921 | ||
16db3d3f | 922 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
923 | |
924 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
925 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
926 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
927 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 928 | |
21d1c5e3 | 929 | for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) |
25f9c081 | 930 | init_user_ns.ucount_max[i] = max_threads/2; |
19659c59 | 931 | |
5ddf994f EB |
932 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); |
933 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); | |
934 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); | |
935 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); | |
21d1c5e3 | 936 | |
19659c59 HR |
937 | #ifdef CONFIG_VMAP_STACK |
938 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", | |
939 | NULL, free_vm_stack_cache); | |
940 | #endif | |
b09be676 | 941 | |
d08b9f0c ST |
942 | scs_init(); |
943 | ||
b09be676 | 944 | lockdep_init_task(&init_task); |
aad42dd4 | 945 | uprobes_init(); |
1da177e4 LT |
946 | } |
947 | ||
52f5684c | 948 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
949 | struct task_struct *src) |
950 | { | |
951 | *dst = *src; | |
952 | return 0; | |
953 | } | |
954 | ||
d4311ff1 AT |
955 | void set_task_stack_end_magic(struct task_struct *tsk) |
956 | { | |
957 | unsigned long *stackend; | |
958 | ||
959 | stackend = end_of_stack(tsk); | |
960 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
961 | } | |
962 | ||
725fc629 | 963 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
964 | { |
965 | struct task_struct *tsk; | |
3e26c149 | 966 | int err; |
1da177e4 | 967 | |
725fc629 AK |
968 | if (node == NUMA_NO_NODE) |
969 | node = tsk_fork_get_node(orig); | |
504f52b5 | 970 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
971 | if (!tsk) |
972 | return NULL; | |
973 | ||
546c42b2 SAS |
974 | err = arch_dup_task_struct(tsk, orig); |
975 | if (err) | |
f19b9f74 | 976 | goto free_tsk; |
1da177e4 | 977 | |
7865aba3 SAS |
978 | err = alloc_thread_stack_node(tsk, node); |
979 | if (err) | |
f19b9f74 | 980 | goto free_tsk; |
ba14a194 | 981 | |
68f24b08 | 982 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
f0b89d39 | 983 | refcount_set(&tsk->stack_refcount, 1); |
68f24b08 | 984 | #endif |
1a03d3f1 | 985 | account_kernel_stack(tsk, 1); |
164c33c6 | 986 | |
d08b9f0c ST |
987 | err = scs_prepare(tsk, node); |
988 | if (err) | |
989 | goto free_stack; | |
990 | ||
dbd95212 KC |
991 | #ifdef CONFIG_SECCOMP |
992 | /* | |
993 | * We must handle setting up seccomp filters once we're under | |
994 | * the sighand lock in case orig has changed between now and | |
995 | * then. Until then, filter must be NULL to avoid messing up | |
996 | * the usage counts on the error path calling free_task. | |
997 | */ | |
998 | tsk->seccomp.filter = NULL; | |
999 | #endif | |
87bec58a AM |
1000 | |
1001 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 1002 | clear_user_return_notifier(tsk); |
f26f9aff | 1003 | clear_tsk_need_resched(tsk); |
d4311ff1 | 1004 | set_task_stack_end_magic(tsk); |
1446e1df | 1005 | clear_syscall_work_syscall_user_dispatch(tsk); |
1da177e4 | 1006 | |
050e9baa | 1007 | #ifdef CONFIG_STACKPROTECTOR |
7cd815bc | 1008 | tsk->stack_canary = get_random_canary(); |
0a425405 | 1009 | #endif |
3bd37062 SAS |
1010 | if (orig->cpus_ptr == &orig->cpus_mask) |
1011 | tsk->cpus_ptr = &tsk->cpus_mask; | |
b90ca8ba | 1012 | dup_user_cpus_ptr(tsk, orig, node); |
0a425405 | 1013 | |
fb0a685c | 1014 | /* |
0ff7b2cf EB |
1015 | * One for the user space visible state that goes away when reaped. |
1016 | * One for the scheduler. | |
fb0a685c | 1017 | */ |
0ff7b2cf EB |
1018 | refcount_set(&tsk->rcu_users, 2); |
1019 | /* One for the rcu users */ | |
1020 | refcount_set(&tsk->usage, 1); | |
6c5c9341 | 1021 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 1022 | tsk->btrace_seq = 0; |
6c5c9341 | 1023 | #endif |
a0aa7f68 | 1024 | tsk->splice_pipe = NULL; |
5640f768 | 1025 | tsk->task_frag.page = NULL; |
093e5840 | 1026 | tsk->wake_q.next = NULL; |
e32cf5df | 1027 | tsk->worker_private = NULL; |
c6a7f572 | 1028 | |
5c9a8750 | 1029 | kcov_task_init(tsk); |
5fbda3ec | 1030 | kmap_local_fork(tsk); |
5c9a8750 | 1031 | |
e41d5818 DV |
1032 | #ifdef CONFIG_FAULT_INJECTION |
1033 | tsk->fail_nth = 0; | |
1034 | #endif | |
1035 | ||
2c323017 JB |
1036 | #ifdef CONFIG_BLK_CGROUP |
1037 | tsk->throttle_queue = NULL; | |
1038 | tsk->use_memdelay = 0; | |
1039 | #endif | |
1040 | ||
a3d29e82 PZ |
1041 | #ifdef CONFIG_IOMMU_SVA |
1042 | tsk->pasid_activated = 0; | |
1043 | #endif | |
1044 | ||
d46eb14b SB |
1045 | #ifdef CONFIG_MEMCG |
1046 | tsk->active_memcg = NULL; | |
1047 | #endif | |
1da177e4 | 1048 | return tsk; |
61c4628b | 1049 | |
b235beea | 1050 | free_stack: |
1a03d3f1 | 1051 | exit_task_stack_account(tsk); |
ba14a194 | 1052 | free_thread_stack(tsk); |
f19b9f74 | 1053 | free_tsk: |
61c4628b SS |
1054 | free_task_struct(tsk); |
1055 | return NULL; | |
1da177e4 LT |
1056 | } |
1057 | ||
23ff4440 | 1058 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 1059 | |
4cb0e11b HK |
1060 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
1061 | ||
1062 | static int __init coredump_filter_setup(char *s) | |
1063 | { | |
1064 | default_dump_filter = | |
1065 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
1066 | MMF_DUMP_FILTER_MASK; | |
1067 | return 1; | |
1068 | } | |
1069 | ||
1070 | __setup("coredump_filter=", coredump_filter_setup); | |
1071 | ||
1da177e4 LT |
1072 | #include <linux/init_task.h> |
1073 | ||
858f0993 AD |
1074 | static void mm_init_aio(struct mm_struct *mm) |
1075 | { | |
1076 | #ifdef CONFIG_AIO | |
1077 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 1078 | mm->ioctx_table = NULL; |
858f0993 AD |
1079 | #endif |
1080 | } | |
1081 | ||
c3f3ce04 AA |
1082 | static __always_inline void mm_clear_owner(struct mm_struct *mm, |
1083 | struct task_struct *p) | |
1084 | { | |
1085 | #ifdef CONFIG_MEMCG | |
1086 | if (mm->owner == p) | |
1087 | WRITE_ONCE(mm->owner, NULL); | |
1088 | #endif | |
1089 | } | |
1090 | ||
33144e84 VD |
1091 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
1092 | { | |
1093 | #ifdef CONFIG_MEMCG | |
1094 | mm->owner = p; | |
1095 | #endif | |
1096 | } | |
1097 | ||
355627f5 EB |
1098 | static void mm_init_uprobes_state(struct mm_struct *mm) |
1099 | { | |
1100 | #ifdef CONFIG_UPROBES | |
1101 | mm->uprobes_state.xol_area = NULL; | |
1102 | #endif | |
1103 | } | |
1104 | ||
bfedb589 EB |
1105 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
1106 | struct user_namespace *user_ns) | |
1da177e4 | 1107 | { |
41f727fd VD |
1108 | mm->mmap = NULL; |
1109 | mm->mm_rb = RB_ROOT; | |
1110 | mm->vmacache_seqnum = 0; | |
1da177e4 LT |
1111 | atomic_set(&mm->mm_users, 1); |
1112 | atomic_set(&mm->mm_count, 1); | |
57efa1fe | 1113 | seqcount_init(&mm->write_protect_seq); |
d8ed45c5 | 1114 | mmap_init_lock(mm); |
1da177e4 | 1115 | INIT_LIST_HEAD(&mm->mmlist); |
af5b0f6a | 1116 | mm_pgtables_bytes_init(mm); |
41f727fd VD |
1117 | mm->map_count = 0; |
1118 | mm->locked_vm = 0; | |
70f8a3ca | 1119 | atomic64_set(&mm->pinned_vm, 0); |
d559db08 | 1120 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 1121 | spin_lock_init(&mm->page_table_lock); |
88aa7cc6 | 1122 | spin_lock_init(&mm->arg_lock); |
41f727fd | 1123 | mm_init_cpumask(mm); |
858f0993 | 1124 | mm_init_aio(mm); |
cf475ad2 | 1125 | mm_init_owner(mm, p); |
a6cbd440 | 1126 | mm_pasid_init(mm); |
2b7e8665 | 1127 | RCU_INIT_POINTER(mm->exe_file, NULL); |
984cfe4e | 1128 | mmu_notifier_subscriptions_init(mm); |
16af97dc | 1129 | init_tlb_flush_pending(mm); |
41f727fd VD |
1130 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
1131 | mm->pmd_huge_pte = NULL; | |
1132 | #endif | |
355627f5 | 1133 | mm_init_uprobes_state(mm); |
13db8c50 | 1134 | hugetlb_count_init(mm); |
1da177e4 | 1135 | |
a0715cc2 AT |
1136 | if (current->mm) { |
1137 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
1138 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
1139 | } else { | |
1140 | mm->flags = default_dump_filter; | |
1da177e4 | 1141 | mm->def_flags = 0; |
a0715cc2 AT |
1142 | } |
1143 | ||
41f727fd VD |
1144 | if (mm_alloc_pgd(mm)) |
1145 | goto fail_nopgd; | |
1146 | ||
1147 | if (init_new_context(p, mm)) | |
1148 | goto fail_nocontext; | |
78fb7466 | 1149 | |
bfedb589 | 1150 | mm->user_ns = get_user_ns(user_ns); |
41f727fd VD |
1151 | return mm; |
1152 | ||
1153 | fail_nocontext: | |
1154 | mm_free_pgd(mm); | |
1155 | fail_nopgd: | |
1da177e4 LT |
1156 | free_mm(mm); |
1157 | return NULL; | |
1158 | } | |
1159 | ||
1160 | /* | |
1161 | * Allocate and initialize an mm_struct. | |
1162 | */ | |
fb0a685c | 1163 | struct mm_struct *mm_alloc(void) |
1da177e4 | 1164 | { |
fb0a685c | 1165 | struct mm_struct *mm; |
1da177e4 LT |
1166 | |
1167 | mm = allocate_mm(); | |
de03c72c KM |
1168 | if (!mm) |
1169 | return NULL; | |
1170 | ||
1171 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 1172 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
1173 | } |
1174 | ||
ec8d7c14 MH |
1175 | static inline void __mmput(struct mm_struct *mm) |
1176 | { | |
1177 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
1178 | ||
1179 | uprobe_clear_state(mm); | |
1180 | exit_aio(mm); | |
1181 | ksm_exit(mm); | |
1182 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
1183 | exit_mmap(mm); | |
6fcb52a5 | 1184 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
1185 | set_mm_exe_file(mm, NULL); |
1186 | if (!list_empty(&mm->mmlist)) { | |
1187 | spin_lock(&mmlist_lock); | |
1188 | list_del(&mm->mmlist); | |
1189 | spin_unlock(&mmlist_lock); | |
1190 | } | |
1191 | if (mm->binfmt) | |
1192 | module_put(mm->binfmt->module); | |
701fac40 | 1193 | mm_pasid_drop(mm); |
ec8d7c14 MH |
1194 | mmdrop(mm); |
1195 | } | |
1196 | ||
1da177e4 LT |
1197 | /* |
1198 | * Decrement the use count and release all resources for an mm. | |
1199 | */ | |
1200 | void mmput(struct mm_struct *mm) | |
1201 | { | |
0ae26f1b AM |
1202 | might_sleep(); |
1203 | ||
ec8d7c14 MH |
1204 | if (atomic_dec_and_test(&mm->mm_users)) |
1205 | __mmput(mm); | |
1206 | } | |
1207 | EXPORT_SYMBOL_GPL(mmput); | |
1208 | ||
a1b2289c SY |
1209 | #ifdef CONFIG_MMU |
1210 | static void mmput_async_fn(struct work_struct *work) | |
1211 | { | |
1212 | struct mm_struct *mm = container_of(work, struct mm_struct, | |
1213 | async_put_work); | |
1214 | ||
1215 | __mmput(mm); | |
1216 | } | |
1217 | ||
1218 | void mmput_async(struct mm_struct *mm) | |
1219 | { | |
1220 | if (atomic_dec_and_test(&mm->mm_users)) { | |
1221 | INIT_WORK(&mm->async_put_work, mmput_async_fn); | |
1222 | schedule_work(&mm->async_put_work); | |
1223 | } | |
1224 | } | |
1225 | #endif | |
1226 | ||
90f31d0e KK |
1227 | /** |
1228 | * set_mm_exe_file - change a reference to the mm's executable file | |
1229 | * | |
1230 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
1231 | * | |
6e399cd1 DB |
1232 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
1233 | * invocations: in mmput() nobody alive left, in execve task is single | |
35d7bdc8 | 1234 | * threaded. |
fe69d560 DH |
1235 | * |
1236 | * Can only fail if new_exe_file != NULL. | |
90f31d0e | 1237 | */ |
fe69d560 | 1238 | int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
38646013 | 1239 | { |
6e399cd1 DB |
1240 | struct file *old_exe_file; |
1241 | ||
1242 | /* | |
1243 | * It is safe to dereference the exe_file without RCU as | |
1244 | * this function is only called if nobody else can access | |
1245 | * this mm -- see comment above for justification. | |
1246 | */ | |
1247 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 1248 | |
fe69d560 DH |
1249 | if (new_exe_file) { |
1250 | /* | |
1251 | * We expect the caller (i.e., sys_execve) to already denied | |
1252 | * write access, so this is unlikely to fail. | |
1253 | */ | |
1254 | if (unlikely(deny_write_access(new_exe_file))) | |
1255 | return -EACCES; | |
38646013 | 1256 | get_file(new_exe_file); |
fe69d560 | 1257 | } |
90f31d0e | 1258 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
fe69d560 DH |
1259 | if (old_exe_file) { |
1260 | allow_write_access(old_exe_file); | |
90f31d0e | 1261 | fput(old_exe_file); |
fe69d560 DH |
1262 | } |
1263 | return 0; | |
38646013 JS |
1264 | } |
1265 | ||
35d7bdc8 DH |
1266 | /** |
1267 | * replace_mm_exe_file - replace a reference to the mm's executable file | |
1268 | * | |
1269 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe), | |
1270 | * dealing with concurrent invocation and without grabbing the mmap lock in | |
1271 | * write mode. | |
1272 | * | |
1273 | * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE). | |
1274 | */ | |
1275 | int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) | |
1276 | { | |
1277 | struct vm_area_struct *vma; | |
1278 | struct file *old_exe_file; | |
1279 | int ret = 0; | |
1280 | ||
1281 | /* Forbid mm->exe_file change if old file still mapped. */ | |
1282 | old_exe_file = get_mm_exe_file(mm); | |
1283 | if (old_exe_file) { | |
1284 | mmap_read_lock(mm); | |
1285 | for (vma = mm->mmap; vma && !ret; vma = vma->vm_next) { | |
1286 | if (!vma->vm_file) | |
1287 | continue; | |
1288 | if (path_equal(&vma->vm_file->f_path, | |
1289 | &old_exe_file->f_path)) | |
1290 | ret = -EBUSY; | |
1291 | } | |
1292 | mmap_read_unlock(mm); | |
1293 | fput(old_exe_file); | |
1294 | if (ret) | |
1295 | return ret; | |
1296 | } | |
1297 | ||
1298 | /* set the new file, lockless */ | |
fe69d560 DH |
1299 | ret = deny_write_access(new_exe_file); |
1300 | if (ret) | |
1301 | return -EACCES; | |
35d7bdc8 | 1302 | get_file(new_exe_file); |
fe69d560 | 1303 | |
35d7bdc8 | 1304 | old_exe_file = xchg(&mm->exe_file, new_exe_file); |
fe69d560 DH |
1305 | if (old_exe_file) { |
1306 | /* | |
1307 | * Don't race with dup_mmap() getting the file and disallowing | |
1308 | * write access while someone might open the file writable. | |
1309 | */ | |
1310 | mmap_read_lock(mm); | |
1311 | allow_write_access(old_exe_file); | |
35d7bdc8 | 1312 | fput(old_exe_file); |
fe69d560 DH |
1313 | mmap_read_unlock(mm); |
1314 | } | |
35d7bdc8 | 1315 | return 0; |
38646013 JS |
1316 | } |
1317 | ||
90f31d0e KK |
1318 | /** |
1319 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
1320 | * | |
1321 | * Returns %NULL if mm has no associated executable file. | |
1322 | * User must release file via fput(). | |
1323 | */ | |
38646013 JS |
1324 | struct file *get_mm_exe_file(struct mm_struct *mm) |
1325 | { | |
1326 | struct file *exe_file; | |
1327 | ||
90f31d0e KK |
1328 | rcu_read_lock(); |
1329 | exe_file = rcu_dereference(mm->exe_file); | |
1330 | if (exe_file && !get_file_rcu(exe_file)) | |
1331 | exe_file = NULL; | |
1332 | rcu_read_unlock(); | |
38646013 JS |
1333 | return exe_file; |
1334 | } | |
1335 | ||
cd81a917 MG |
1336 | /** |
1337 | * get_task_exe_file - acquire a reference to the task's executable file | |
1338 | * | |
1339 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
1340 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
1341 | * User must release file via fput(). | |
1342 | */ | |
1343 | struct file *get_task_exe_file(struct task_struct *task) | |
1344 | { | |
1345 | struct file *exe_file = NULL; | |
1346 | struct mm_struct *mm; | |
1347 | ||
1348 | task_lock(task); | |
1349 | mm = task->mm; | |
1350 | if (mm) { | |
1351 | if (!(task->flags & PF_KTHREAD)) | |
1352 | exe_file = get_mm_exe_file(mm); | |
1353 | } | |
1354 | task_unlock(task); | |
1355 | return exe_file; | |
1356 | } | |
38646013 | 1357 | |
1da177e4 LT |
1358 | /** |
1359 | * get_task_mm - acquire a reference to the task's mm | |
1360 | * | |
246bb0b1 | 1361 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
1362 | * this kernel workthread has transiently adopted a user mm with use_mm, |
1363 | * to do its AIO) is not set and if so returns a reference to it, after | |
1364 | * bumping up the use count. User must release the mm via mmput() | |
1365 | * after use. Typically used by /proc and ptrace. | |
1366 | */ | |
1367 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1368 | { | |
1369 | struct mm_struct *mm; | |
1370 | ||
1371 | task_lock(task); | |
1372 | mm = task->mm; | |
1373 | if (mm) { | |
246bb0b1 | 1374 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1375 | mm = NULL; |
1376 | else | |
3fce371b | 1377 | mmget(mm); |
1da177e4 LT |
1378 | } |
1379 | task_unlock(task); | |
1380 | return mm; | |
1381 | } | |
1382 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1383 | ||
8cdb878d CY |
1384 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1385 | { | |
1386 | struct mm_struct *mm; | |
1387 | int err; | |
1388 | ||
f7cfd871 | 1389 | err = down_read_killable(&task->signal->exec_update_lock); |
8cdb878d CY |
1390 | if (err) |
1391 | return ERR_PTR(err); | |
1392 | ||
1393 | mm = get_task_mm(task); | |
1394 | if (mm && mm != current->mm && | |
1395 | !ptrace_may_access(task, mode)) { | |
1396 | mmput(mm); | |
1397 | mm = ERR_PTR(-EACCES); | |
1398 | } | |
f7cfd871 | 1399 | up_read(&task->signal->exec_update_lock); |
8cdb878d CY |
1400 | |
1401 | return mm; | |
1402 | } | |
1403 | ||
57b59c4a | 1404 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1405 | { |
d68b46fe | 1406 | struct completion *vfork; |
c415c3b4 | 1407 | |
d68b46fe ON |
1408 | task_lock(tsk); |
1409 | vfork = tsk->vfork_done; | |
1410 | if (likely(vfork)) { | |
1411 | tsk->vfork_done = NULL; | |
1412 | complete(vfork); | |
1413 | } | |
1414 | task_unlock(tsk); | |
1415 | } | |
1416 | ||
1417 | static int wait_for_vfork_done(struct task_struct *child, | |
1418 | struct completion *vfork) | |
1419 | { | |
1420 | int killed; | |
1421 | ||
1422 | freezer_do_not_count(); | |
76f969e8 | 1423 | cgroup_enter_frozen(); |
d68b46fe | 1424 | killed = wait_for_completion_killable(vfork); |
76f969e8 | 1425 | cgroup_leave_frozen(false); |
d68b46fe ON |
1426 | freezer_count(); |
1427 | ||
1428 | if (killed) { | |
1429 | task_lock(child); | |
1430 | child->vfork_done = NULL; | |
1431 | task_unlock(child); | |
1432 | } | |
1433 | ||
1434 | put_task_struct(child); | |
1435 | return killed; | |
c415c3b4 ON |
1436 | } |
1437 | ||
1da177e4 LT |
1438 | /* Please note the differences between mmput and mm_release. |
1439 | * mmput is called whenever we stop holding onto a mm_struct, | |
1440 | * error success whatever. | |
1441 | * | |
1442 | * mm_release is called after a mm_struct has been removed | |
1443 | * from the current process. | |
1444 | * | |
1445 | * This difference is important for error handling, when we | |
1446 | * only half set up a mm_struct for a new process and need to restore | |
1447 | * the old one. Because we mmput the new mm_struct before | |
1448 | * restoring the old one. . . | |
1449 | * Eric Biederman 10 January 1998 | |
1450 | */ | |
4610ba7a | 1451 | static void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1da177e4 | 1452 | { |
0326f5a9 SD |
1453 | uprobe_free_utask(tsk); |
1454 | ||
1da177e4 LT |
1455 | /* Get rid of any cached register state */ |
1456 | deactivate_mm(tsk, mm); | |
1457 | ||
fec1d011 | 1458 | /* |
735f2770 MH |
1459 | * Signal userspace if we're not exiting with a core dump |
1460 | * because we want to leave the value intact for debugging | |
1461 | * purposes. | |
fec1d011 | 1462 | */ |
9c8a8228 | 1463 | if (tsk->clear_child_tid) { |
92307383 | 1464 | if (atomic_read(&mm->mm_users) > 1) { |
9c8a8228 ED |
1465 | /* |
1466 | * We don't check the error code - if userspace has | |
1467 | * not set up a proper pointer then tough luck. | |
1468 | */ | |
1469 | put_user(0, tsk->clear_child_tid); | |
2de0db99 DB |
1470 | do_futex(tsk->clear_child_tid, FUTEX_WAKE, |
1471 | 1, NULL, NULL, 0, 0); | |
9c8a8228 | 1472 | } |
1da177e4 | 1473 | tsk->clear_child_tid = NULL; |
1da177e4 | 1474 | } |
f7505d64 KK |
1475 | |
1476 | /* | |
1477 | * All done, finally we can wake up parent and return this mm to him. | |
1478 | * Also kthread_stop() uses this completion for synchronization. | |
1479 | */ | |
1480 | if (tsk->vfork_done) | |
1481 | complete_vfork_done(tsk); | |
1da177e4 LT |
1482 | } |
1483 | ||
4610ba7a TG |
1484 | void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1485 | { | |
150d7158 | 1486 | futex_exit_release(tsk); |
4610ba7a TG |
1487 | mm_release(tsk, mm); |
1488 | } | |
1489 | ||
1490 | void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1491 | { | |
150d7158 | 1492 | futex_exec_release(tsk); |
4610ba7a TG |
1493 | mm_release(tsk, mm); |
1494 | } | |
1495 | ||
13585fa0 NA |
1496 | /** |
1497 | * dup_mm() - duplicates an existing mm structure | |
1498 | * @tsk: the task_struct with which the new mm will be associated. | |
1499 | * @oldmm: the mm to duplicate. | |
1500 | * | |
1501 | * Allocates a new mm structure and duplicates the provided @oldmm structure | |
1502 | * content into it. | |
1503 | * | |
1504 | * Return: the duplicated mm or NULL on failure. | |
a0a7ec30 | 1505 | */ |
13585fa0 NA |
1506 | static struct mm_struct *dup_mm(struct task_struct *tsk, |
1507 | struct mm_struct *oldmm) | |
a0a7ec30 | 1508 | { |
13585fa0 | 1509 | struct mm_struct *mm; |
a0a7ec30 JD |
1510 | int err; |
1511 | ||
a0a7ec30 JD |
1512 | mm = allocate_mm(); |
1513 | if (!mm) | |
1514 | goto fail_nomem; | |
1515 | ||
1516 | memcpy(mm, oldmm, sizeof(*mm)); | |
1517 | ||
bfedb589 | 1518 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1519 | goto fail_nomem; |
1520 | ||
a0a7ec30 JD |
1521 | err = dup_mmap(mm, oldmm); |
1522 | if (err) | |
1523 | goto free_pt; | |
1524 | ||
1525 | mm->hiwater_rss = get_mm_rss(mm); | |
1526 | mm->hiwater_vm = mm->total_vm; | |
1527 | ||
801460d0 HS |
1528 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1529 | goto free_pt; | |
1530 | ||
a0a7ec30 JD |
1531 | return mm; |
1532 | ||
1533 | free_pt: | |
801460d0 HS |
1534 | /* don't put binfmt in mmput, we haven't got module yet */ |
1535 | mm->binfmt = NULL; | |
c3f3ce04 | 1536 | mm_init_owner(mm, NULL); |
a0a7ec30 JD |
1537 | mmput(mm); |
1538 | ||
1539 | fail_nomem: | |
1540 | return NULL; | |
a0a7ec30 JD |
1541 | } |
1542 | ||
fb0a685c | 1543 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1544 | { |
fb0a685c | 1545 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1546 | |
1547 | tsk->min_flt = tsk->maj_flt = 0; | |
1548 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1549 | #ifdef CONFIG_DETECT_HUNG_TASK |
1550 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
a2e51445 | 1551 | tsk->last_switch_time = 0; |
17406b82 | 1552 | #endif |
1da177e4 LT |
1553 | |
1554 | tsk->mm = NULL; | |
1555 | tsk->active_mm = NULL; | |
1556 | ||
1557 | /* | |
1558 | * Are we cloning a kernel thread? | |
1559 | * | |
1560 | * We need to steal a active VM for that.. | |
1561 | */ | |
1562 | oldmm = current->mm; | |
1563 | if (!oldmm) | |
1564 | return 0; | |
1565 | ||
615d6e87 DB |
1566 | /* initialize the new vmacache entries */ |
1567 | vmacache_flush(tsk); | |
1568 | ||
1da177e4 | 1569 | if (clone_flags & CLONE_VM) { |
3fce371b | 1570 | mmget(oldmm); |
1da177e4 | 1571 | mm = oldmm; |
a6895399 REB |
1572 | } else { |
1573 | mm = dup_mm(tsk, current->mm); | |
1574 | if (!mm) | |
1575 | return -ENOMEM; | |
1da177e4 LT |
1576 | } |
1577 | ||
1da177e4 LT |
1578 | tsk->mm = mm; |
1579 | tsk->active_mm = mm; | |
1580 | return 0; | |
1da177e4 LT |
1581 | } |
1582 | ||
a39bc516 | 1583 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1584 | { |
498052bb | 1585 | struct fs_struct *fs = current->fs; |
1da177e4 | 1586 | if (clone_flags & CLONE_FS) { |
498052bb | 1587 | /* tsk->fs is already what we want */ |
2a4419b5 | 1588 | spin_lock(&fs->lock); |
498052bb | 1589 | if (fs->in_exec) { |
2a4419b5 | 1590 | spin_unlock(&fs->lock); |
498052bb AV |
1591 | return -EAGAIN; |
1592 | } | |
1593 | fs->users++; | |
2a4419b5 | 1594 | spin_unlock(&fs->lock); |
1da177e4 LT |
1595 | return 0; |
1596 | } | |
498052bb | 1597 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1598 | if (!tsk->fs) |
1599 | return -ENOMEM; | |
1600 | return 0; | |
1601 | } | |
1602 | ||
fb0a685c | 1603 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1604 | { |
1605 | struct files_struct *oldf, *newf; | |
1606 | int error = 0; | |
1607 | ||
1608 | /* | |
1609 | * A background process may not have any files ... | |
1610 | */ | |
1611 | oldf = current->files; | |
1612 | if (!oldf) | |
1613 | goto out; | |
1614 | ||
1615 | if (clone_flags & CLONE_FILES) { | |
1616 | atomic_inc(&oldf->count); | |
1617 | goto out; | |
1618 | } | |
1619 | ||
60997c3d | 1620 | newf = dup_fd(oldf, NR_OPEN_MAX, &error); |
a016f338 JD |
1621 | if (!newf) |
1622 | goto out; | |
1623 | ||
1624 | tsk->files = newf; | |
1625 | error = 0; | |
1626 | out: | |
1627 | return error; | |
1628 | } | |
1629 | ||
a39bc516 | 1630 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1631 | { |
1632 | struct sighand_struct *sig; | |
1633 | ||
60348802 | 1634 | if (clone_flags & CLONE_SIGHAND) { |
d036bda7 | 1635 | refcount_inc(¤t->sighand->count); |
1da177e4 LT |
1636 | return 0; |
1637 | } | |
1638 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
0c282b06 | 1639 | RCU_INIT_POINTER(tsk->sighand, sig); |
1da177e4 LT |
1640 | if (!sig) |
1641 | return -ENOMEM; | |
9d7fb042 | 1642 | |
d036bda7 | 1643 | refcount_set(&sig->count, 1); |
06e62a46 | 1644 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1645 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
06e62a46 | 1646 | spin_unlock_irq(¤t->sighand->siglock); |
b612e5df CB |
1647 | |
1648 | /* Reset all signal handler not set to SIG_IGN to SIG_DFL. */ | |
1649 | if (clone_flags & CLONE_CLEAR_SIGHAND) | |
1650 | flush_signal_handlers(tsk, 0); | |
1651 | ||
1da177e4 LT |
1652 | return 0; |
1653 | } | |
1654 | ||
a7e5328a | 1655 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1656 | { |
d036bda7 | 1657 | if (refcount_dec_and_test(&sighand->count)) { |
d80e731e | 1658 | signalfd_cleanup(sighand); |
392809b2 | 1659 | /* |
5f0d5a3a | 1660 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it |
392809b2 ON |
1661 | * without an RCU grace period, see __lock_task_sighand(). |
1662 | */ | |
c81addc9 | 1663 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1664 | } |
c81addc9 ON |
1665 | } |
1666 | ||
f06febc9 FM |
1667 | /* |
1668 | * Initialize POSIX timer handling for a thread group. | |
1669 | */ | |
1670 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1671 | { | |
2b69942f | 1672 | struct posix_cputimers *pct = &sig->posix_cputimers; |
78d7d407 JS |
1673 | unsigned long cpu_limit; |
1674 | ||
316c1608 | 1675 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
3a245c0f | 1676 | posix_cputimers_group_init(pct, cpu_limit); |
f06febc9 FM |
1677 | } |
1678 | ||
a39bc516 | 1679 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1680 | { |
1681 | struct signal_struct *sig; | |
1da177e4 | 1682 | |
4ab6c083 | 1683 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1684 | return 0; |
490dea45 | 1685 | |
a56704ef | 1686 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1687 | tsk->signal = sig; |
1688 | if (!sig) | |
1689 | return -ENOMEM; | |
1690 | ||
b3ac022c | 1691 | sig->nr_threads = 1; |
1da177e4 | 1692 | atomic_set(&sig->live, 1); |
60d4de3f | 1693 | refcount_set(&sig->sigcnt, 1); |
0c740d0a ON |
1694 | |
1695 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1696 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1697 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1698 | ||
1da177e4 | 1699 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1700 | sig->curr_target = tsk; |
1da177e4 | 1701 | init_sigpending(&sig->shared_pending); |
c3ad2c3b | 1702 | INIT_HLIST_HEAD(&sig->multiprocess); |
e78c3496 | 1703 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1704 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1705 | |
baa73d9e | 1706 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1707 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1708 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1709 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1710 | #endif |
1da177e4 | 1711 | |
1da177e4 LT |
1712 | task_lock(current->group_leader); |
1713 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1714 | task_unlock(current->group_leader); | |
1715 | ||
6279a751 ON |
1716 | posix_cpu_timers_init_group(sig); |
1717 | ||
522ed776 | 1718 | tty_audit_fork(sig); |
5091faa4 | 1719 | sched_autogroup_fork(sig); |
522ed776 | 1720 | |
a63d83f4 | 1721 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1722 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1723 | |
9b1bf12d | 1724 | mutex_init(&sig->cred_guard_mutex); |
f7cfd871 | 1725 | init_rwsem(&sig->exec_update_lock); |
9b1bf12d | 1726 | |
1da177e4 LT |
1727 | return 0; |
1728 | } | |
1729 | ||
dbd95212 KC |
1730 | static void copy_seccomp(struct task_struct *p) |
1731 | { | |
1732 | #ifdef CONFIG_SECCOMP | |
1733 | /* | |
1734 | * Must be called with sighand->lock held, which is common to | |
1735 | * all threads in the group. Holding cred_guard_mutex is not | |
1736 | * needed because this new task is not yet running and cannot | |
1737 | * be racing exec. | |
1738 | */ | |
69f6a34b | 1739 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1740 | |
1741 | /* Ref-count the new filter user, and assign it. */ | |
1742 | get_seccomp_filter(current); | |
1743 | p->seccomp = current->seccomp; | |
1744 | ||
1745 | /* | |
1746 | * Explicitly enable no_new_privs here in case it got set | |
1747 | * between the task_struct being duplicated and holding the | |
1748 | * sighand lock. The seccomp state and nnp must be in sync. | |
1749 | */ | |
1750 | if (task_no_new_privs(current)) | |
1751 | task_set_no_new_privs(p); | |
1752 | ||
1753 | /* | |
1754 | * If the parent gained a seccomp mode after copying thread | |
1755 | * flags and between before we held the sighand lock, we have | |
1756 | * to manually enable the seccomp thread flag here. | |
1757 | */ | |
1758 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
23d67a54 | 1759 | set_task_syscall_work(p, SECCOMP); |
dbd95212 KC |
1760 | #endif |
1761 | } | |
1762 | ||
17da2bd9 | 1763 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1764 | { |
1765 | current->clear_child_tid = tidptr; | |
1766 | ||
b488893a | 1767 | return task_pid_vnr(current); |
1da177e4 LT |
1768 | } |
1769 | ||
a39bc516 | 1770 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1771 | { |
1d615482 | 1772 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1773 | #ifdef CONFIG_RT_MUTEXES |
a23ba907 | 1774 | p->pi_waiters = RB_ROOT_CACHED; |
e96a7705 | 1775 | p->pi_top_task = NULL; |
23f78d4a | 1776 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1777 | #endif |
1778 | } | |
1779 | ||
2c470475 EB |
1780 | static inline void init_task_pid_links(struct task_struct *task) |
1781 | { | |
1782 | enum pid_type type; | |
1783 | ||
96e1e984 | 1784 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) |
2c470475 | 1785 | INIT_HLIST_NODE(&task->pid_links[type]); |
2c470475 EB |
1786 | } |
1787 | ||
81907739 ON |
1788 | static inline void |
1789 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1790 | { | |
2c470475 EB |
1791 | if (type == PIDTYPE_PID) |
1792 | task->thread_pid = pid; | |
1793 | else | |
1794 | task->signal->pids[type] = pid; | |
81907739 ON |
1795 | } |
1796 | ||
6bfbaa51 IM |
1797 | static inline void rcu_copy_process(struct task_struct *p) |
1798 | { | |
1799 | #ifdef CONFIG_PREEMPT_RCU | |
1800 | p->rcu_read_lock_nesting = 0; | |
1801 | p->rcu_read_unlock_special.s = 0; | |
1802 | p->rcu_blocked_node = NULL; | |
1803 | INIT_LIST_HEAD(&p->rcu_node_entry); | |
1804 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1805 | #ifdef CONFIG_TASKS_RCU | |
1806 | p->rcu_tasks_holdout = false; | |
1807 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); | |
1808 | p->rcu_tasks_idle_cpu = -1; | |
1809 | #endif /* #ifdef CONFIG_TASKS_RCU */ | |
d5f177d3 PM |
1810 | #ifdef CONFIG_TASKS_TRACE_RCU |
1811 | p->trc_reader_nesting = 0; | |
276c4104 | 1812 | p->trc_reader_special.s = 0; |
d5f177d3 PM |
1813 | INIT_LIST_HEAD(&p->trc_holdout_list); |
1814 | #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ | |
6bfbaa51 IM |
1815 | } |
1816 | ||
3695eae5 CB |
1817 | struct pid *pidfd_pid(const struct file *file) |
1818 | { | |
1819 | if (file->f_op == &pidfd_fops) | |
1820 | return file->private_data; | |
1821 | ||
1822 | return ERR_PTR(-EBADF); | |
1823 | } | |
1824 | ||
b3e58382 CB |
1825 | static int pidfd_release(struct inode *inode, struct file *file) |
1826 | { | |
1827 | struct pid *pid = file->private_data; | |
1828 | ||
1829 | file->private_data = NULL; | |
1830 | put_pid(pid); | |
1831 | return 0; | |
1832 | } | |
1833 | ||
1834 | #ifdef CONFIG_PROC_FS | |
15d42eb2 CK |
1835 | /** |
1836 | * pidfd_show_fdinfo - print information about a pidfd | |
1837 | * @m: proc fdinfo file | |
1838 | * @f: file referencing a pidfd | |
1839 | * | |
1840 | * Pid: | |
1841 | * This function will print the pid that a given pidfd refers to in the | |
1842 | * pid namespace of the procfs instance. | |
1843 | * If the pid namespace of the process is not a descendant of the pid | |
1844 | * namespace of the procfs instance 0 will be shown as its pid. This is | |
1845 | * similar to calling getppid() on a process whose parent is outside of | |
1846 | * its pid namespace. | |
1847 | * | |
1848 | * NSpid: | |
1849 | * If pid namespaces are supported then this function will also print | |
1850 | * the pid of a given pidfd refers to for all descendant pid namespaces | |
1851 | * starting from the current pid namespace of the instance, i.e. the | |
1852 | * Pid field and the first entry in the NSpid field will be identical. | |
1853 | * If the pid namespace of the process is not a descendant of the pid | |
1854 | * namespace of the procfs instance 0 will be shown as its first NSpid | |
1855 | * entry and no others will be shown. | |
1856 | * Note that this differs from the Pid and NSpid fields in | |
1857 | * /proc/<pid>/status where Pid and NSpid are always shown relative to | |
1858 | * the pid namespace of the procfs instance. The difference becomes | |
1859 | * obvious when sending around a pidfd between pid namespaces from a | |
a8ca6b13 | 1860 | * different branch of the tree, i.e. where no ancestral relation is |
15d42eb2 CK |
1861 | * present between the pid namespaces: |
1862 | * - create two new pid namespaces ns1 and ns2 in the initial pid | |
1863 | * namespace (also take care to create new mount namespaces in the | |
1864 | * new pid namespace and mount procfs) | |
1865 | * - create a process with a pidfd in ns1 | |
1866 | * - send pidfd from ns1 to ns2 | |
1867 | * - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid | |
1868 | * have exactly one entry, which is 0 | |
1869 | */ | |
b3e58382 CB |
1870 | static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) |
1871 | { | |
b3e58382 | 1872 | struct pid *pid = f->private_data; |
3d6d8da4 CB |
1873 | struct pid_namespace *ns; |
1874 | pid_t nr = -1; | |
15d42eb2 | 1875 | |
3d6d8da4 | 1876 | if (likely(pid_has_task(pid, PIDTYPE_PID))) { |
9d78edea | 1877 | ns = proc_pid_ns(file_inode(m->file)->i_sb); |
3d6d8da4 CB |
1878 | nr = pid_nr_ns(pid, ns); |
1879 | } | |
1880 | ||
1881 | seq_put_decimal_ll(m, "Pid:\t", nr); | |
b3e58382 | 1882 | |
15d42eb2 | 1883 | #ifdef CONFIG_PID_NS |
3d6d8da4 CB |
1884 | seq_put_decimal_ll(m, "\nNSpid:\t", nr); |
1885 | if (nr > 0) { | |
15d42eb2 | 1886 | int i; |
b3e58382 | 1887 | |
15d42eb2 CK |
1888 | /* If nr is non-zero it means that 'pid' is valid and that |
1889 | * ns, i.e. the pid namespace associated with the procfs | |
1890 | * instance, is in the pid namespace hierarchy of pid. | |
1891 | * Start at one below the already printed level. | |
1892 | */ | |
1893 | for (i = ns->level + 1; i <= pid->level; i++) | |
3d6d8da4 | 1894 | seq_put_decimal_ll(m, "\t", pid->numbers[i].nr); |
15d42eb2 CK |
1895 | } |
1896 | #endif | |
b3e58382 CB |
1897 | seq_putc(m, '\n'); |
1898 | } | |
1899 | #endif | |
1900 | ||
b53b0b9d JFG |
1901 | /* |
1902 | * Poll support for process exit notification. | |
1903 | */ | |
9e77716a | 1904 | static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) |
b53b0b9d | 1905 | { |
b53b0b9d | 1906 | struct pid *pid = file->private_data; |
9e77716a | 1907 | __poll_t poll_flags = 0; |
b53b0b9d JFG |
1908 | |
1909 | poll_wait(file, &pid->wait_pidfd, pts); | |
1910 | ||
b53b0b9d JFG |
1911 | /* |
1912 | * Inform pollers only when the whole thread group exits. | |
1913 | * If the thread group leader exits before all other threads in the | |
1914 | * group, then poll(2) should block, similar to the wait(2) family. | |
1915 | */ | |
38fd525a | 1916 | if (thread_group_exited(pid)) |
9e77716a | 1917 | poll_flags = EPOLLIN | EPOLLRDNORM; |
b53b0b9d JFG |
1918 | |
1919 | return poll_flags; | |
1920 | } | |
1921 | ||
b3e58382 CB |
1922 | const struct file_operations pidfd_fops = { |
1923 | .release = pidfd_release, | |
b53b0b9d | 1924 | .poll = pidfd_poll, |
b3e58382 CB |
1925 | #ifdef CONFIG_PROC_FS |
1926 | .show_fdinfo = pidfd_show_fdinfo, | |
1927 | #endif | |
1928 | }; | |
1929 | ||
c3f3ce04 AA |
1930 | static void __delayed_free_task(struct rcu_head *rhp) |
1931 | { | |
1932 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); | |
1933 | ||
1934 | free_task(tsk); | |
1935 | } | |
1936 | ||
1937 | static __always_inline void delayed_free_task(struct task_struct *tsk) | |
1938 | { | |
1939 | if (IS_ENABLED(CONFIG_MEMCG)) | |
1940 | call_rcu(&tsk->rcu, __delayed_free_task); | |
1941 | else | |
1942 | free_task(tsk); | |
1943 | } | |
1944 | ||
67197a4f SB |
1945 | static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk) |
1946 | { | |
1947 | /* Skip if kernel thread */ | |
1948 | if (!tsk->mm) | |
1949 | return; | |
1950 | ||
1951 | /* Skip if spawning a thread or using vfork */ | |
1952 | if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM) | |
1953 | return; | |
1954 | ||
1955 | /* We need to synchronize with __set_oom_adj */ | |
1956 | mutex_lock(&oom_adj_mutex); | |
1957 | set_bit(MMF_MULTIPROCESS, &tsk->mm->flags); | |
1958 | /* Update the values in case they were changed after copy_signal */ | |
1959 | tsk->signal->oom_score_adj = current->signal->oom_score_adj; | |
1960 | tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min; | |
1961 | mutex_unlock(&oom_adj_mutex); | |
1962 | } | |
1963 | ||
1da177e4 LT |
1964 | /* |
1965 | * This creates a new process as a copy of the old one, | |
1966 | * but does not actually start it yet. | |
1967 | * | |
1968 | * It copies the registers, and all the appropriate | |
1969 | * parts of the process environment (as per the clone | |
1970 | * flags). The actual kick-off is left to the caller. | |
1971 | */ | |
0766f788 | 1972 | static __latent_entropy struct task_struct *copy_process( |
09a05394 | 1973 | struct pid *pid, |
3033f14a | 1974 | int trace, |
7f192e3c CB |
1975 | int node, |
1976 | struct kernel_clone_args *args) | |
1da177e4 | 1977 | { |
b3e58382 | 1978 | int pidfd = -1, retval; |
a24efe62 | 1979 | struct task_struct *p; |
c3ad2c3b | 1980 | struct multiprocess_signals delayed; |
6fd2fe49 | 1981 | struct file *pidfile = NULL; |
7f192e3c | 1982 | u64 clone_flags = args->flags; |
769071ac | 1983 | struct nsproxy *nsp = current->nsproxy; |
1da177e4 | 1984 | |
667b6094 MPS |
1985 | /* |
1986 | * Don't allow sharing the root directory with processes in a different | |
1987 | * namespace | |
1988 | */ | |
1da177e4 LT |
1989 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
1990 | return ERR_PTR(-EINVAL); | |
1991 | ||
e66eded8 EB |
1992 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
1993 | return ERR_PTR(-EINVAL); | |
1994 | ||
1da177e4 LT |
1995 | /* |
1996 | * Thread groups must share signals as well, and detached threads | |
1997 | * can only be started up within the thread group. | |
1998 | */ | |
1999 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
2000 | return ERR_PTR(-EINVAL); | |
2001 | ||
2002 | /* | |
2003 | * Shared signal handlers imply shared VM. By way of the above, | |
2004 | * thread groups also imply shared VM. Blocking this case allows | |
2005 | * for various simplifications in other code. | |
2006 | */ | |
2007 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
2008 | return ERR_PTR(-EINVAL); | |
2009 | ||
123be07b SB |
2010 | /* |
2011 | * Siblings of global init remain as zombies on exit since they are | |
2012 | * not reaped by their parent (swapper). To solve this and to avoid | |
2013 | * multi-rooted process trees, prevent global and container-inits | |
2014 | * from creating siblings. | |
2015 | */ | |
2016 | if ((clone_flags & CLONE_PARENT) && | |
2017 | current->signal->flags & SIGNAL_UNKILLABLE) | |
2018 | return ERR_PTR(-EINVAL); | |
2019 | ||
8382fcac | 2020 | /* |
40a0d32d | 2021 | * If the new process will be in a different pid or user namespace |
faf00da5 | 2022 | * do not allow it to share a thread group with the forking task. |
8382fcac | 2023 | */ |
faf00da5 | 2024 | if (clone_flags & CLONE_THREAD) { |
40a0d32d | 2025 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
769071ac AV |
2026 | (task_active_pid_ns(current) != nsp->pid_ns_for_children)) |
2027 | return ERR_PTR(-EINVAL); | |
2028 | } | |
2029 | ||
2030 | /* | |
2031 | * If the new process will be in a different time namespace | |
2032 | * do not allow it to share VM or a thread group with the forking task. | |
2033 | */ | |
2034 | if (clone_flags & (CLONE_THREAD | CLONE_VM)) { | |
2035 | if (nsp->time_ns != nsp->time_ns_for_children) | |
40a0d32d ON |
2036 | return ERR_PTR(-EINVAL); |
2037 | } | |
8382fcac | 2038 | |
b3e58382 | 2039 | if (clone_flags & CLONE_PIDFD) { |
b3e58382 | 2040 | /* |
b3e58382 CB |
2041 | * - CLONE_DETACHED is blocked so that we can potentially |
2042 | * reuse it later for CLONE_PIDFD. | |
2043 | * - CLONE_THREAD is blocked until someone really needs it. | |
2044 | */ | |
7f192e3c | 2045 | if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) |
b3e58382 | 2046 | return ERR_PTR(-EINVAL); |
b3e58382 CB |
2047 | } |
2048 | ||
c3ad2c3b EB |
2049 | /* |
2050 | * Force any signals received before this point to be delivered | |
2051 | * before the fork happens. Collect up signals sent to multiple | |
2052 | * processes that happen during the fork and delay them so that | |
2053 | * they appear to happen after the fork. | |
2054 | */ | |
2055 | sigemptyset(&delayed.signal); | |
2056 | INIT_HLIST_NODE(&delayed.node); | |
2057 | ||
2058 | spin_lock_irq(¤t->sighand->siglock); | |
2059 | if (!(clone_flags & CLONE_THREAD)) | |
2060 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess); | |
2061 | recalc_sigpending(); | |
2062 | spin_unlock_irq(¤t->sighand->siglock); | |
2063 | retval = -ERESTARTNOINTR; | |
66ae0d1e | 2064 | if (task_sigpending(current)) |
c3ad2c3b EB |
2065 | goto fork_out; |
2066 | ||
1da177e4 | 2067 | retval = -ENOMEM; |
725fc629 | 2068 | p = dup_task_struct(current, node); |
1da177e4 LT |
2069 | if (!p) |
2070 | goto fork_out; | |
b16b3855 JA |
2071 | if (args->io_thread) { |
2072 | /* | |
2073 | * Mark us an IO worker, and block any signal that isn't | |
2074 | * fatal or STOP | |
2075 | */ | |
cc440e87 | 2076 | p->flags |= PF_IO_WORKER; |
b16b3855 JA |
2077 | siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2078 | } | |
1da177e4 | 2079 | |
7f192e3c | 2080 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL; |
4d6501dc VN |
2081 | /* |
2082 | * Clear TID on mm_release()? | |
2083 | */ | |
7f192e3c | 2084 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL; |
4d6501dc | 2085 | |
f7e8b616 SR |
2086 | ftrace_graph_init_task(p); |
2087 | ||
bea493a0 PZ |
2088 | rt_mutex_init_task(p); |
2089 | ||
a21ee605 | 2090 | lockdep_assert_irqs_enabled(); |
d12c1a37 | 2091 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
2092 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
2093 | #endif | |
8f2f9c4d EB |
2094 | retval = copy_creds(p, clone_flags); |
2095 | if (retval < 0) | |
2096 | goto bad_fork_free; | |
2097 | ||
1da177e4 | 2098 | retval = -EAGAIN; |
21d1c5e3 | 2099 | if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { |
b57922b6 EP |
2100 | if (p->real_cred->user != INIT_USER && |
2101 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
8f2f9c4d | 2102 | goto bad_fork_cleanup_count; |
1da177e4 | 2103 | } |
72fa5997 | 2104 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 2105 | |
1da177e4 LT |
2106 | /* |
2107 | * If multiple threads are within copy_process(), then this check | |
2108 | * triggers too late. This doesn't hurt, the check is only there | |
2109 | * to stop root fork bombs. | |
2110 | */ | |
04ec93fe | 2111 | retval = -EAGAIN; |
c17d1a3a | 2112 | if (data_race(nr_threads >= max_threads)) |
1da177e4 LT |
2113 | goto bad_fork_cleanup_count; |
2114 | ||
ca74e92b | 2115 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
a8ea6fc9 | 2116 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY); |
514ddb44 | 2117 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
2118 | INIT_LIST_HEAD(&p->children); |
2119 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 2120 | rcu_copy_process(p); |
1da177e4 LT |
2121 | p->vfork_done = NULL; |
2122 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 2123 | |
1da177e4 LT |
2124 | init_sigpending(&p->pending); |
2125 | ||
64861634 | 2126 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 2127 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 2128 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 2129 | #endif |
9d7fb042 PZ |
2130 | prev_cputime_init(&p->prev_cputime); |
2131 | ||
6a61671b | 2132 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
bac5b6b6 FW |
2133 | seqcount_init(&p->vtime.seqcount); |
2134 | p->vtime.starttime = 0; | |
2135 | p->vtime.state = VTIME_INACTIVE; | |
6a61671b FW |
2136 | #endif |
2137 | ||
0f212204 JA |
2138 | #ifdef CONFIG_IO_URING |
2139 | p->io_uring = NULL; | |
2140 | #endif | |
2141 | ||
a3a2e76c KH |
2142 | #if defined(SPLIT_RSS_COUNTING) |
2143 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
2144 | #endif | |
172ba844 | 2145 | |
6976675d AV |
2146 | p->default_timer_slack_ns = current->timer_slack_ns; |
2147 | ||
eb414681 JW |
2148 | #ifdef CONFIG_PSI |
2149 | p->psi_flags = 0; | |
2150 | #endif | |
2151 | ||
5995477a | 2152 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
2153 | acct_clear_integrals(p); |
2154 | ||
3a245c0f | 2155 | posix_cputimers_init(&p->posix_cputimers); |
1da177e4 | 2156 | |
1da177e4 | 2157 | p->io_context = NULL; |
c0b0ae8a | 2158 | audit_set_context(p, NULL); |
b4f48b63 | 2159 | cgroup_fork(p); |
40966e31 EB |
2160 | if (p->flags & PF_KTHREAD) { |
2161 | if (!set_kthread_struct(p)) | |
ff8288ff | 2162 | goto bad_fork_cleanup_delayacct; |
40966e31 | 2163 | } |
1da177e4 | 2164 | #ifdef CONFIG_NUMA |
846a16bf | 2165 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
2166 | if (IS_ERR(p->mempolicy)) { |
2167 | retval = PTR_ERR(p->mempolicy); | |
2168 | p->mempolicy = NULL; | |
ff8288ff | 2169 | goto bad_fork_cleanup_delayacct; |
fb0a685c | 2170 | } |
1da177e4 | 2171 | #endif |
778d3b0f MH |
2172 | #ifdef CONFIG_CPUSETS |
2173 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
2174 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
b7505861 | 2175 | seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock); |
778d3b0f | 2176 | #endif |
de30a2b3 | 2177 | #ifdef CONFIG_TRACE_IRQFLAGS |
0584df9c ME |
2178 | memset(&p->irqtrace, 0, sizeof(p->irqtrace)); |
2179 | p->irqtrace.hardirq_disable_ip = _THIS_IP_; | |
2180 | p->irqtrace.softirq_enable_ip = _THIS_IP_; | |
2181 | p->softirqs_enabled = 1; | |
2182 | p->softirq_context = 0; | |
de30a2b3 | 2183 | #endif |
8bcbde54 DH |
2184 | |
2185 | p->pagefault_disabled = 0; | |
2186 | ||
fbb9ce95 | 2187 | #ifdef CONFIG_LOCKDEP |
b09be676 | 2188 | lockdep_init_task(p); |
fbb9ce95 | 2189 | #endif |
1da177e4 | 2190 | |
408894ee IM |
2191 | #ifdef CONFIG_DEBUG_MUTEXES |
2192 | p->blocked_on = NULL; /* not blocked yet */ | |
2193 | #endif | |
cafe5635 KO |
2194 | #ifdef CONFIG_BCACHE |
2195 | p->sequential_io = 0; | |
2196 | p->sequential_io_avg = 0; | |
2197 | #endif | |
a10787e6 SL |
2198 | #ifdef CONFIG_BPF_SYSCALL |
2199 | RCU_INIT_POINTER(p->bpf_storage, NULL); | |
c7603cfa | 2200 | p->bpf_ctx = NULL; |
a10787e6 | 2201 | #endif |
0f481406 | 2202 | |
3c90e6e9 | 2203 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
2204 | retval = sched_fork(clone_flags, p); |
2205 | if (retval) | |
2206 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 2207 | |
2b26f0aa | 2208 | retval = perf_event_init_task(p, clone_flags); |
6ab423e0 PZ |
2209 | if (retval) |
2210 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
2211 | retval = audit_alloc(p); |
2212 | if (retval) | |
6c72e350 | 2213 | goto bad_fork_cleanup_perf; |
1da177e4 | 2214 | /* copy all the process information */ |
ab602f79 | 2215 | shm_init_task(p); |
e4e55b47 | 2216 | retval = security_task_alloc(p, clone_flags); |
fb0a685c | 2217 | if (retval) |
1da177e4 | 2218 | goto bad_fork_cleanup_audit; |
e4e55b47 TH |
2219 | retval = copy_semundo(clone_flags, p); |
2220 | if (retval) | |
2221 | goto bad_fork_cleanup_security; | |
fb0a685c DRO |
2222 | retval = copy_files(clone_flags, p); |
2223 | if (retval) | |
1da177e4 | 2224 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
2225 | retval = copy_fs(clone_flags, p); |
2226 | if (retval) | |
1da177e4 | 2227 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
2228 | retval = copy_sighand(clone_flags, p); |
2229 | if (retval) | |
1da177e4 | 2230 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
2231 | retval = copy_signal(clone_flags, p); |
2232 | if (retval) | |
1da177e4 | 2233 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
2234 | retval = copy_mm(clone_flags, p); |
2235 | if (retval) | |
1da177e4 | 2236 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
2237 | retval = copy_namespaces(clone_flags, p); |
2238 | if (retval) | |
d84f4f99 | 2239 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
2240 | retval = copy_io(clone_flags, p); |
2241 | if (retval) | |
fd0928df | 2242 | goto bad_fork_cleanup_namespaces; |
714acdbd | 2243 | retval = copy_thread(clone_flags, args->stack, args->stack_size, p, args->tls); |
1da177e4 | 2244 | if (retval) |
fd0928df | 2245 | goto bad_fork_cleanup_io; |
1da177e4 | 2246 | |
afaef01c AP |
2247 | stackleak_task_init(p); |
2248 | ||
425fb2b4 | 2249 | if (pid != &init_struct_pid) { |
49cb2fc4 AR |
2250 | pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid, |
2251 | args->set_tid_size); | |
35f71bc0 MH |
2252 | if (IS_ERR(pid)) { |
2253 | retval = PTR_ERR(pid); | |
0740aa5f | 2254 | goto bad_fork_cleanup_thread; |
35f71bc0 | 2255 | } |
425fb2b4 PE |
2256 | } |
2257 | ||
b3e58382 CB |
2258 | /* |
2259 | * This has to happen after we've potentially unshared the file | |
2260 | * descriptor table (so that the pidfd doesn't leak into the child | |
2261 | * if the fd table isn't shared). | |
2262 | */ | |
2263 | if (clone_flags & CLONE_PIDFD) { | |
6fd2fe49 | 2264 | retval = get_unused_fd_flags(O_RDWR | O_CLOEXEC); |
b3e58382 CB |
2265 | if (retval < 0) |
2266 | goto bad_fork_free_pid; | |
2267 | ||
2268 | pidfd = retval; | |
6fd2fe49 AV |
2269 | |
2270 | pidfile = anon_inode_getfile("[pidfd]", &pidfd_fops, pid, | |
2271 | O_RDWR | O_CLOEXEC); | |
2272 | if (IS_ERR(pidfile)) { | |
2273 | put_unused_fd(pidfd); | |
28dd29c0 | 2274 | retval = PTR_ERR(pidfile); |
6fd2fe49 AV |
2275 | goto bad_fork_free_pid; |
2276 | } | |
2277 | get_pid(pid); /* held by pidfile now */ | |
2278 | ||
7f192e3c | 2279 | retval = put_user(pidfd, args->pidfd); |
b3e58382 CB |
2280 | if (retval) |
2281 | goto bad_fork_put_pidfd; | |
2282 | } | |
2283 | ||
73c10101 JA |
2284 | #ifdef CONFIG_BLOCK |
2285 | p->plug = NULL; | |
2286 | #endif | |
ba31c1a4 TG |
2287 | futex_init_task(p); |
2288 | ||
f9a3879a GM |
2289 | /* |
2290 | * sigaltstack should be cleared when sharing the same VM | |
2291 | */ | |
2292 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 2293 | sas_ss_reset(p); |
f9a3879a | 2294 | |
1da177e4 | 2295 | /* |
6580807d ON |
2296 | * Syscall tracing and stepping should be turned off in the |
2297 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 2298 | */ |
6580807d | 2299 | user_disable_single_step(p); |
64c19ba2 | 2300 | clear_task_syscall_work(p, SYSCALL_TRACE); |
64eb35f7 GKB |
2301 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) |
2302 | clear_task_syscall_work(p, SYSCALL_EMU); | |
ed75e8d5 | 2303 | #endif |
e02c9b0d | 2304 | clear_tsk_latency_tracing(p); |
1da177e4 | 2305 | |
1da177e4 | 2306 | /* ok, now we should be set up.. */ |
18c830df ON |
2307 | p->pid = pid_nr(pid); |
2308 | if (clone_flags & CLONE_THREAD) { | |
18c830df ON |
2309 | p->group_leader = current->group_leader; |
2310 | p->tgid = current->tgid; | |
2311 | } else { | |
18c830df ON |
2312 | p->group_leader = p; |
2313 | p->tgid = p->pid; | |
2314 | } | |
5f8aadd8 | 2315 | |
9d823e8f WF |
2316 | p->nr_dirtied = 0; |
2317 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 2318 | p->dirty_paused_when = 0; |
9d823e8f | 2319 | |
bb8cbbfe | 2320 | p->pdeath_signal = 0; |
47e65328 | 2321 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 2322 | p->task_works = NULL; |
ca7752ca | 2323 | clear_posix_cputimers_work(p); |
1da177e4 | 2324 | |
d741bf41 PZ |
2325 | #ifdef CONFIG_KRETPROBES |
2326 | p->kretprobe_instances.first = NULL; | |
2327 | #endif | |
54ecbe6f MH |
2328 | #ifdef CONFIG_RETHOOK |
2329 | p->rethooks.first = NULL; | |
2330 | #endif | |
d741bf41 | 2331 | |
7e47682e AS |
2332 | /* |
2333 | * Ensure that the cgroup subsystem policies allow the new process to be | |
7b7b8a2c | 2334 | * forked. It should be noted that the new process's css_set can be changed |
7e47682e AS |
2335 | * between here and cgroup_post_fork() if an organisation operation is in |
2336 | * progress. | |
2337 | */ | |
ef2c41cf | 2338 | retval = cgroup_can_fork(p, args); |
7e47682e | 2339 | if (retval) |
5a5cf5cb | 2340 | goto bad_fork_put_pidfd; |
7e47682e | 2341 | |
b1e82065 PZ |
2342 | /* |
2343 | * Now that the cgroups are pinned, re-clone the parent cgroup and put | |
2344 | * the new task on the correct runqueue. All this *before* the task | |
2345 | * becomes visible. | |
2346 | * | |
2347 | * This isn't part of ->can_fork() because while the re-cloning is | |
2348 | * cgroup specific, it unconditionally needs to place the task on a | |
2349 | * runqueue. | |
2350 | */ | |
2351 | sched_cgroup_fork(p, args); | |
2352 | ||
7b558513 DH |
2353 | /* |
2354 | * From this point on we must avoid any synchronous user-space | |
2355 | * communication until we take the tasklist-lock. In particular, we do | |
2356 | * not want user-space to be able to predict the process start-time by | |
2357 | * stalling fork(2) after we recorded the start_time but before it is | |
2358 | * visible to the system. | |
2359 | */ | |
2360 | ||
2361 | p->start_time = ktime_get_ns(); | |
cf25e24d | 2362 | p->start_boottime = ktime_get_boottime_ns(); |
7b558513 | 2363 | |
18c830df ON |
2364 | /* |
2365 | * Make it visible to the rest of the system, but dont wake it up yet. | |
2366 | * Need tasklist lock for parent etc handling! | |
2367 | */ | |
1da177e4 LT |
2368 | write_lock_irq(&tasklist_lock); |
2369 | ||
1da177e4 | 2370 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 2371 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 2372 | p->real_parent = current->real_parent; |
2d5516cb | 2373 | p->parent_exec_id = current->parent_exec_id; |
b4e00444 EW |
2374 | if (clone_flags & CLONE_THREAD) |
2375 | p->exit_signal = -1; | |
2376 | else | |
2377 | p->exit_signal = current->group_leader->exit_signal; | |
2d5516cb | 2378 | } else { |
1da177e4 | 2379 | p->real_parent = current; |
2d5516cb | 2380 | p->parent_exec_id = current->self_exec_id; |
b4e00444 | 2381 | p->exit_signal = args->exit_signal; |
2d5516cb | 2382 | } |
1da177e4 | 2383 | |
d83a7cb3 JP |
2384 | klp_copy_process(p); |
2385 | ||
85dd3f61 PZ |
2386 | sched_core_fork(p); |
2387 | ||
3f17da69 | 2388 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 2389 | |
dbd95212 KC |
2390 | /* |
2391 | * Copy seccomp details explicitly here, in case they were changed | |
2392 | * before holding sighand lock. | |
2393 | */ | |
2394 | copy_seccomp(p); | |
2395 | ||
d7822b1e MD |
2396 | rseq_fork(p, clone_flags); |
2397 | ||
4ca1d3ee | 2398 | /* Don't start children in a dying pid namespace */ |
e8cfbc24 | 2399 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { |
3fd37226 KT |
2400 | retval = -ENOMEM; |
2401 | goto bad_fork_cancel_cgroup; | |
2402 | } | |
4a2c7a78 | 2403 | |
7673bf55 EB |
2404 | /* Let kill terminate clone/fork in the middle */ |
2405 | if (fatal_signal_pending(current)) { | |
2406 | retval = -EINTR; | |
2407 | goto bad_fork_cancel_cgroup; | |
2408 | } | |
2409 | ||
2c470475 | 2410 | init_task_pid_links(p); |
73b9ebfe | 2411 | if (likely(p->pid)) { |
4b9d33e6 | 2412 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 2413 | |
81907739 | 2414 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 2415 | if (thread_group_leader(p)) { |
6883f81a | 2416 | init_task_pid(p, PIDTYPE_TGID, pid); |
81907739 ON |
2417 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
2418 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
2419 | ||
1c4042c2 | 2420 | if (is_child_reaper(pid)) { |
17cf22c3 | 2421 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
2422 | p->signal->flags |= SIGNAL_UNKILLABLE; |
2423 | } | |
c3ad2c3b | 2424 | p->signal->shared_pending.signal = delayed.signal; |
9c9f4ded | 2425 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
2426 | /* |
2427 | * Inherit has_child_subreaper flag under the same | |
2428 | * tasklist_lock with adding child to the process tree | |
2429 | * for propagate_has_child_subreaper optimization. | |
2430 | */ | |
2431 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
2432 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 2433 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 2434 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
6883f81a | 2435 | attach_pid(p, PIDTYPE_TGID); |
81907739 ON |
2436 | attach_pid(p, PIDTYPE_PGID); |
2437 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 2438 | __this_cpu_inc(process_counts); |
80628ca0 ON |
2439 | } else { |
2440 | current->signal->nr_threads++; | |
2441 | atomic_inc(¤t->signal->live); | |
60d4de3f | 2442 | refcount_inc(¤t->signal->sigcnt); |
924de3b8 | 2443 | task_join_group_stop(p); |
80628ca0 ON |
2444 | list_add_tail_rcu(&p->thread_group, |
2445 | &p->group_leader->thread_group); | |
0c740d0a ON |
2446 | list_add_tail_rcu(&p->thread_node, |
2447 | &p->signal->thread_head); | |
73b9ebfe | 2448 | } |
81907739 | 2449 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 2450 | nr_threads++; |
1da177e4 | 2451 | } |
1da177e4 | 2452 | total_forks++; |
c3ad2c3b | 2453 | hlist_del_init(&delayed.node); |
3f17da69 | 2454 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 2455 | syscall_tracepoint_update(p); |
1da177e4 | 2456 | write_unlock_irq(&tasklist_lock); |
4af4206b | 2457 | |
ddc204b5 WL |
2458 | if (pidfile) |
2459 | fd_install(pidfd, pidfile); | |
2460 | ||
c13cf856 | 2461 | proc_fork_connector(p); |
b1e82065 | 2462 | sched_post_fork(p); |
ef2c41cf | 2463 | cgroup_post_fork(p, args); |
cdd6c482 | 2464 | perf_event_fork(p); |
43d2b113 KH |
2465 | |
2466 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 2467 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 2468 | |
67197a4f SB |
2469 | copy_oom_score_adj(clone_flags, p); |
2470 | ||
1da177e4 LT |
2471 | return p; |
2472 | ||
7e47682e | 2473 | bad_fork_cancel_cgroup: |
85dd3f61 | 2474 | sched_core_free(p); |
3fd37226 KT |
2475 | spin_unlock(¤t->sighand->siglock); |
2476 | write_unlock_irq(&tasklist_lock); | |
ef2c41cf | 2477 | cgroup_cancel_fork(p, args); |
b3e58382 | 2478 | bad_fork_put_pidfd: |
6fd2fe49 AV |
2479 | if (clone_flags & CLONE_PIDFD) { |
2480 | fput(pidfile); | |
2481 | put_unused_fd(pidfd); | |
2482 | } | |
425fb2b4 PE |
2483 | bad_fork_free_pid: |
2484 | if (pid != &init_struct_pid) | |
2485 | free_pid(pid); | |
0740aa5f JS |
2486 | bad_fork_cleanup_thread: |
2487 | exit_thread(p); | |
fd0928df | 2488 | bad_fork_cleanup_io: |
b69f2292 LR |
2489 | if (p->io_context) |
2490 | exit_io_context(p); | |
ab516013 | 2491 | bad_fork_cleanup_namespaces: |
444f378b | 2492 | exit_task_namespaces(p); |
1da177e4 | 2493 | bad_fork_cleanup_mm: |
c3f3ce04 AA |
2494 | if (p->mm) { |
2495 | mm_clear_owner(p->mm, p); | |
1da177e4 | 2496 | mmput(p->mm); |
c3f3ce04 | 2497 | } |
1da177e4 | 2498 | bad_fork_cleanup_signal: |
4ab6c083 | 2499 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 2500 | free_signal_struct(p->signal); |
1da177e4 | 2501 | bad_fork_cleanup_sighand: |
a7e5328a | 2502 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
2503 | bad_fork_cleanup_fs: |
2504 | exit_fs(p); /* blocking */ | |
2505 | bad_fork_cleanup_files: | |
2506 | exit_files(p); /* blocking */ | |
2507 | bad_fork_cleanup_semundo: | |
2508 | exit_sem(p); | |
e4e55b47 TH |
2509 | bad_fork_cleanup_security: |
2510 | security_task_free(p); | |
1da177e4 LT |
2511 | bad_fork_cleanup_audit: |
2512 | audit_free(p); | |
6c72e350 | 2513 | bad_fork_cleanup_perf: |
cdd6c482 | 2514 | perf_event_free_task(p); |
6c72e350 | 2515 | bad_fork_cleanup_policy: |
b09be676 | 2516 | lockdep_free_task(p); |
1da177e4 | 2517 | #ifdef CONFIG_NUMA |
f0be3d32 | 2518 | mpol_put(p->mempolicy); |
1da177e4 | 2519 | #endif |
ff8288ff | 2520 | bad_fork_cleanup_delayacct: |
35df17c5 | 2521 | delayacct_tsk_free(p); |
1da177e4 | 2522 | bad_fork_cleanup_count: |
21d1c5e3 | 2523 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); |
e0e81739 | 2524 | exit_creds(p); |
1da177e4 | 2525 | bad_fork_free: |
2f064a59 | 2526 | WRITE_ONCE(p->__state, TASK_DEAD); |
1a03d3f1 | 2527 | exit_task_stack_account(p); |
68f24b08 | 2528 | put_task_stack(p); |
c3f3ce04 | 2529 | delayed_free_task(p); |
fe7d37d1 | 2530 | fork_out: |
c3ad2c3b EB |
2531 | spin_lock_irq(¤t->sighand->siglock); |
2532 | hlist_del_init(&delayed.node); | |
2533 | spin_unlock_irq(¤t->sighand->siglock); | |
fe7d37d1 | 2534 | return ERR_PTR(retval); |
1da177e4 LT |
2535 | } |
2536 | ||
2c470475 | 2537 | static inline void init_idle_pids(struct task_struct *idle) |
f106eee1 ON |
2538 | { |
2539 | enum pid_type type; | |
2540 | ||
2541 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
2c470475 EB |
2542 | INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */ |
2543 | init_task_pid(idle, type, &init_struct_pid); | |
f106eee1 ON |
2544 | } |
2545 | } | |
2546 | ||
f1a0a376 | 2547 | struct task_struct * __init fork_idle(int cpu) |
1da177e4 | 2548 | { |
36c8b586 | 2549 | struct task_struct *task; |
7f192e3c CB |
2550 | struct kernel_clone_args args = { |
2551 | .flags = CLONE_VM, | |
2552 | }; | |
2553 | ||
2554 | task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args); | |
f106eee1 | 2555 | if (!IS_ERR(task)) { |
2c470475 | 2556 | init_idle_pids(task); |
753ca4f3 | 2557 | init_idle(task, cpu); |
f106eee1 | 2558 | } |
73b9ebfe | 2559 | |
1da177e4 LT |
2560 | return task; |
2561 | } | |
2562 | ||
13585fa0 NA |
2563 | struct mm_struct *copy_init_mm(void) |
2564 | { | |
2565 | return dup_mm(NULL, &init_mm); | |
2566 | } | |
2567 | ||
cc440e87 JA |
2568 | /* |
2569 | * This is like kernel_clone(), but shaved down and tailored to just | |
2570 | * creating io_uring workers. It returns a created task, or an error pointer. | |
2571 | * The returned task is inactive, and the caller must fire it up through | |
2572 | * wake_up_new_task(p). All signals are blocked in the created task. | |
2573 | */ | |
2574 | struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) | |
2575 | { | |
2576 | unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD| | |
2577 | CLONE_IO; | |
2578 | struct kernel_clone_args args = { | |
2579 | .flags = ((lower_32_bits(flags) | CLONE_VM | | |
2580 | CLONE_UNTRACED) & ~CSIGNAL), | |
2581 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
2582 | .stack = (unsigned long)fn, | |
2583 | .stack_size = (unsigned long)arg, | |
2584 | .io_thread = 1, | |
2585 | }; | |
cc440e87 | 2586 | |
b16b3855 | 2587 | return copy_process(NULL, 0, node, &args); |
cc440e87 JA |
2588 | } |
2589 | ||
1da177e4 LT |
2590 | /* |
2591 | * Ok, this is the main fork-routine. | |
2592 | * | |
2593 | * It copies the process, and if successful kick-starts | |
2594 | * it and waits for it to finish using the VM if required. | |
a0eb9abd ES |
2595 | * |
2596 | * args->exit_signal is expected to be checked for sanity by the caller. | |
1da177e4 | 2597 | */ |
cad6967a | 2598 | pid_t kernel_clone(struct kernel_clone_args *args) |
1da177e4 | 2599 | { |
7f192e3c | 2600 | u64 clone_flags = args->flags; |
9f5325aa MPS |
2601 | struct completion vfork; |
2602 | struct pid *pid; | |
1da177e4 LT |
2603 | struct task_struct *p; |
2604 | int trace = 0; | |
cad6967a | 2605 | pid_t nr; |
1da177e4 | 2606 | |
3af8588c CB |
2607 | /* |
2608 | * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument | |
2609 | * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are | |
2610 | * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate | |
2611 | * field in struct clone_args and it still doesn't make sense to have | |
2612 | * them both point at the same memory location. Performing this check | |
2613 | * here has the advantage that we don't need to have a separate helper | |
2614 | * to check for legacy clone(). | |
2615 | */ | |
2616 | if ((args->flags & CLONE_PIDFD) && | |
2617 | (args->flags & CLONE_PARENT_SETTID) && | |
2618 | (args->pidfd == args->parent_tid)) | |
2619 | return -EINVAL; | |
2620 | ||
09a05394 | 2621 | /* |
4b9d33e6 TH |
2622 | * Determine whether and which event to report to ptracer. When |
2623 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
2624 | * requested, no event is reported; otherwise, report if the event | |
2625 | * for the type of forking is enabled. | |
09a05394 | 2626 | */ |
e80d6661 | 2627 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
2628 | if (clone_flags & CLONE_VFORK) |
2629 | trace = PTRACE_EVENT_VFORK; | |
7f192e3c | 2630 | else if (args->exit_signal != SIGCHLD) |
4b9d33e6 TH |
2631 | trace = PTRACE_EVENT_CLONE; |
2632 | else | |
2633 | trace = PTRACE_EVENT_FORK; | |
2634 | ||
2635 | if (likely(!ptrace_event_enabled(current, trace))) | |
2636 | trace = 0; | |
2637 | } | |
1da177e4 | 2638 | |
7f192e3c | 2639 | p = copy_process(NULL, trace, NUMA_NO_NODE, args); |
38addce8 | 2640 | add_latent_entropy(); |
9f5325aa MPS |
2641 | |
2642 | if (IS_ERR(p)) | |
2643 | return PTR_ERR(p); | |
2644 | ||
1da177e4 LT |
2645 | /* |
2646 | * Do this prior waking up the new thread - the thread pointer | |
2647 | * might get invalid after that point, if the thread exits quickly. | |
2648 | */ | |
9f5325aa | 2649 | trace_sched_process_fork(current, p); |
0a16b607 | 2650 | |
9f5325aa MPS |
2651 | pid = get_task_pid(p, PIDTYPE_PID); |
2652 | nr = pid_vnr(pid); | |
30e49c26 | 2653 | |
9f5325aa | 2654 | if (clone_flags & CLONE_PARENT_SETTID) |
7f192e3c | 2655 | put_user(nr, args->parent_tid); |
a6f5e063 | 2656 | |
9f5325aa MPS |
2657 | if (clone_flags & CLONE_VFORK) { |
2658 | p->vfork_done = &vfork; | |
2659 | init_completion(&vfork); | |
2660 | get_task_struct(p); | |
2661 | } | |
1da177e4 | 2662 | |
9f5325aa | 2663 | wake_up_new_task(p); |
09a05394 | 2664 | |
9f5325aa MPS |
2665 | /* forking complete and child started to run, tell ptracer */ |
2666 | if (unlikely(trace)) | |
2667 | ptrace_event_pid(trace, pid); | |
4e52365f | 2668 | |
9f5325aa MPS |
2669 | if (clone_flags & CLONE_VFORK) { |
2670 | if (!wait_for_vfork_done(p, &vfork)) | |
2671 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); | |
1da177e4 | 2672 | } |
9f5325aa MPS |
2673 | |
2674 | put_pid(pid); | |
92476d7f | 2675 | return nr; |
1da177e4 LT |
2676 | } |
2677 | ||
2aa3a7f8 AV |
2678 | /* |
2679 | * Create a kernel thread. | |
2680 | */ | |
2681 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2682 | { | |
7f192e3c | 2683 | struct kernel_clone_args args = { |
3f2c788a CB |
2684 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2685 | CLONE_UNTRACED) & ~CSIGNAL), | |
2686 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
7f192e3c CB |
2687 | .stack = (unsigned long)fn, |
2688 | .stack_size = (unsigned long)arg, | |
2689 | }; | |
2690 | ||
cad6967a | 2691 | return kernel_clone(&args); |
2aa3a7f8 | 2692 | } |
2aa3a7f8 | 2693 | |
d2125043 AV |
2694 | #ifdef __ARCH_WANT_SYS_FORK |
2695 | SYSCALL_DEFINE0(fork) | |
2696 | { | |
2697 | #ifdef CONFIG_MMU | |
7f192e3c CB |
2698 | struct kernel_clone_args args = { |
2699 | .exit_signal = SIGCHLD, | |
2700 | }; | |
2701 | ||
cad6967a | 2702 | return kernel_clone(&args); |
d2125043 AV |
2703 | #else |
2704 | /* can not support in nommu mode */ | |
5d59e182 | 2705 | return -EINVAL; |
d2125043 AV |
2706 | #endif |
2707 | } | |
2708 | #endif | |
2709 | ||
2710 | #ifdef __ARCH_WANT_SYS_VFORK | |
2711 | SYSCALL_DEFINE0(vfork) | |
2712 | { | |
7f192e3c CB |
2713 | struct kernel_clone_args args = { |
2714 | .flags = CLONE_VFORK | CLONE_VM, | |
2715 | .exit_signal = SIGCHLD, | |
2716 | }; | |
2717 | ||
cad6967a | 2718 | return kernel_clone(&args); |
d2125043 AV |
2719 | } |
2720 | #endif | |
2721 | ||
2722 | #ifdef __ARCH_WANT_SYS_CLONE | |
2723 | #ifdef CONFIG_CLONE_BACKWARDS | |
2724 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2725 | int __user *, parent_tidptr, | |
3033f14a | 2726 | unsigned long, tls, |
d2125043 AV |
2727 | int __user *, child_tidptr) |
2728 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
2729 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
2730 | int __user *, parent_tidptr, | |
2731 | int __user *, child_tidptr, | |
3033f14a | 2732 | unsigned long, tls) |
dfa9771a MS |
2733 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
2734 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2735 | int, stack_size, | |
2736 | int __user *, parent_tidptr, | |
2737 | int __user *, child_tidptr, | |
3033f14a | 2738 | unsigned long, tls) |
d2125043 AV |
2739 | #else |
2740 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2741 | int __user *, parent_tidptr, | |
2742 | int __user *, child_tidptr, | |
3033f14a | 2743 | unsigned long, tls) |
d2125043 AV |
2744 | #endif |
2745 | { | |
7f192e3c | 2746 | struct kernel_clone_args args = { |
3f2c788a | 2747 | .flags = (lower_32_bits(clone_flags) & ~CSIGNAL), |
7f192e3c CB |
2748 | .pidfd = parent_tidptr, |
2749 | .child_tid = child_tidptr, | |
2750 | .parent_tid = parent_tidptr, | |
3f2c788a | 2751 | .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL), |
7f192e3c CB |
2752 | .stack = newsp, |
2753 | .tls = tls, | |
2754 | }; | |
2755 | ||
cad6967a | 2756 | return kernel_clone(&args); |
7f192e3c | 2757 | } |
d68dbb0c | 2758 | #endif |
7f192e3c | 2759 | |
d68dbb0c | 2760 | #ifdef __ARCH_WANT_SYS_CLONE3 |
dd499f7a | 2761 | |
7f192e3c CB |
2762 | noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, |
2763 | struct clone_args __user *uargs, | |
f14c234b | 2764 | size_t usize) |
7f192e3c | 2765 | { |
f14c234b | 2766 | int err; |
7f192e3c | 2767 | struct clone_args args; |
49cb2fc4 | 2768 | pid_t *kset_tid = kargs->set_tid; |
7f192e3c | 2769 | |
a966dcfe ES |
2770 | BUILD_BUG_ON(offsetofend(struct clone_args, tls) != |
2771 | CLONE_ARGS_SIZE_VER0); | |
2772 | BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) != | |
2773 | CLONE_ARGS_SIZE_VER1); | |
2774 | BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != | |
2775 | CLONE_ARGS_SIZE_VER2); | |
2776 | BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); | |
2777 | ||
f14c234b | 2778 | if (unlikely(usize > PAGE_SIZE)) |
7f192e3c | 2779 | return -E2BIG; |
f14c234b | 2780 | if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) |
7f192e3c CB |
2781 | return -EINVAL; |
2782 | ||
f14c234b AS |
2783 | err = copy_struct_from_user(&args, sizeof(args), uargs, usize); |
2784 | if (err) | |
2785 | return err; | |
7f192e3c | 2786 | |
49cb2fc4 AR |
2787 | if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL)) |
2788 | return -EINVAL; | |
2789 | ||
2790 | if (unlikely(!args.set_tid && args.set_tid_size > 0)) | |
2791 | return -EINVAL; | |
2792 | ||
2793 | if (unlikely(args.set_tid && args.set_tid_size == 0)) | |
2794 | return -EINVAL; | |
2795 | ||
a0eb9abd ES |
2796 | /* |
2797 | * Verify that higher 32bits of exit_signal are unset and that | |
2798 | * it is a valid signal | |
2799 | */ | |
2800 | if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) || | |
2801 | !valid_signal(args.exit_signal))) | |
2802 | return -EINVAL; | |
2803 | ||
62173872 ES |
2804 | if ((args.flags & CLONE_INTO_CGROUP) && |
2805 | (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2)) | |
ef2c41cf CB |
2806 | return -EINVAL; |
2807 | ||
7f192e3c CB |
2808 | *kargs = (struct kernel_clone_args){ |
2809 | .flags = args.flags, | |
2810 | .pidfd = u64_to_user_ptr(args.pidfd), | |
2811 | .child_tid = u64_to_user_ptr(args.child_tid), | |
2812 | .parent_tid = u64_to_user_ptr(args.parent_tid), | |
2813 | .exit_signal = args.exit_signal, | |
2814 | .stack = args.stack, | |
2815 | .stack_size = args.stack_size, | |
2816 | .tls = args.tls, | |
49cb2fc4 | 2817 | .set_tid_size = args.set_tid_size, |
ef2c41cf | 2818 | .cgroup = args.cgroup, |
7f192e3c CB |
2819 | }; |
2820 | ||
49cb2fc4 AR |
2821 | if (args.set_tid && |
2822 | copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid), | |
2823 | (kargs->set_tid_size * sizeof(pid_t)))) | |
2824 | return -EFAULT; | |
2825 | ||
2826 | kargs->set_tid = kset_tid; | |
2827 | ||
7f192e3c CB |
2828 | return 0; |
2829 | } | |
2830 | ||
fa729c4d CB |
2831 | /** |
2832 | * clone3_stack_valid - check and prepare stack | |
2833 | * @kargs: kernel clone args | |
2834 | * | |
2835 | * Verify that the stack arguments userspace gave us are sane. | |
2836 | * In addition, set the stack direction for userspace since it's easy for us to | |
2837 | * determine. | |
2838 | */ | |
2839 | static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) | |
2840 | { | |
2841 | if (kargs->stack == 0) { | |
2842 | if (kargs->stack_size > 0) | |
2843 | return false; | |
2844 | } else { | |
2845 | if (kargs->stack_size == 0) | |
2846 | return false; | |
2847 | ||
2848 | if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) | |
2849 | return false; | |
2850 | ||
2851 | #if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64) | |
2852 | kargs->stack += kargs->stack_size; | |
2853 | #endif | |
2854 | } | |
2855 | ||
2856 | return true; | |
2857 | } | |
2858 | ||
2859 | static bool clone3_args_valid(struct kernel_clone_args *kargs) | |
7f192e3c | 2860 | { |
b612e5df | 2861 | /* Verify that no unknown flags are passed along. */ |
ef2c41cf CB |
2862 | if (kargs->flags & |
2863 | ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP)) | |
7f192e3c CB |
2864 | return false; |
2865 | ||
2866 | /* | |
a8ca6b13 XC |
2867 | * - make the CLONE_DETACHED bit reusable for clone3 |
2868 | * - make the CSIGNAL bits reusable for clone3 | |
7f192e3c CB |
2869 | */ |
2870 | if (kargs->flags & (CLONE_DETACHED | CSIGNAL)) | |
2871 | return false; | |
2872 | ||
b612e5df CB |
2873 | if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) == |
2874 | (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) | |
2875 | return false; | |
2876 | ||
7f192e3c CB |
2877 | if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) && |
2878 | kargs->exit_signal) | |
2879 | return false; | |
2880 | ||
fa729c4d CB |
2881 | if (!clone3_stack_valid(kargs)) |
2882 | return false; | |
2883 | ||
7f192e3c CB |
2884 | return true; |
2885 | } | |
2886 | ||
501bd016 CB |
2887 | /** |
2888 | * clone3 - create a new process with specific properties | |
2889 | * @uargs: argument structure | |
2890 | * @size: size of @uargs | |
2891 | * | |
2892 | * clone3() is the extensible successor to clone()/clone2(). | |
2893 | * It takes a struct as argument that is versioned by its size. | |
2894 | * | |
2895 | * Return: On success, a positive PID for the child process. | |
2896 | * On error, a negative errno number. | |
2897 | */ | |
7f192e3c CB |
2898 | SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) |
2899 | { | |
2900 | int err; | |
2901 | ||
2902 | struct kernel_clone_args kargs; | |
49cb2fc4 AR |
2903 | pid_t set_tid[MAX_PID_NS_LEVEL]; |
2904 | ||
2905 | kargs.set_tid = set_tid; | |
7f192e3c CB |
2906 | |
2907 | err = copy_clone_args_from_user(&kargs, uargs, size); | |
2908 | if (err) | |
2909 | return err; | |
2910 | ||
2911 | if (!clone3_args_valid(&kargs)) | |
2912 | return -EINVAL; | |
2913 | ||
cad6967a | 2914 | return kernel_clone(&kargs); |
d2125043 AV |
2915 | } |
2916 | #endif | |
2917 | ||
0f1b92cb ON |
2918 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
2919 | { | |
2920 | struct task_struct *leader, *parent, *child; | |
2921 | int res; | |
2922 | ||
2923 | read_lock(&tasklist_lock); | |
2924 | leader = top = top->group_leader; | |
2925 | down: | |
2926 | for_each_thread(leader, parent) { | |
2927 | list_for_each_entry(child, &parent->children, sibling) { | |
2928 | res = visitor(child, data); | |
2929 | if (res) { | |
2930 | if (res < 0) | |
2931 | goto out; | |
2932 | leader = child; | |
2933 | goto down; | |
2934 | } | |
2935 | up: | |
2936 | ; | |
2937 | } | |
2938 | } | |
2939 | ||
2940 | if (leader != top) { | |
2941 | child = leader; | |
2942 | parent = child->real_parent; | |
2943 | leader = parent->group_leader; | |
2944 | goto up; | |
2945 | } | |
2946 | out: | |
2947 | read_unlock(&tasklist_lock); | |
2948 | } | |
2949 | ||
5fd63b30 RT |
2950 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
2951 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
2952 | #endif | |
2953 | ||
51cc5068 | 2954 | static void sighand_ctor(void *data) |
aa1757f9 ON |
2955 | { |
2956 | struct sighand_struct *sighand = data; | |
2957 | ||
a35afb83 | 2958 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 2959 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
2960 | } |
2961 | ||
1da177e4 LT |
2962 | void __init proc_caches_init(void) |
2963 | { | |
c1a2f7f0 RR |
2964 | unsigned int mm_size; |
2965 | ||
1da177e4 LT |
2966 | sighand_cachep = kmem_cache_create("sighand_cache", |
2967 | sizeof(struct sighand_struct), 0, | |
5f0d5a3a | 2968 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| |
75f296d9 | 2969 | SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
2970 | signal_cachep = kmem_cache_create("signal_cache", |
2971 | sizeof(struct signal_struct), 0, | |
75f296d9 | 2972 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2973 | NULL); |
20c2df83 | 2974 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 2975 | sizeof(struct files_struct), 0, |
75f296d9 | 2976 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2977 | NULL); |
20c2df83 | 2978 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 2979 | sizeof(struct fs_struct), 0, |
75f296d9 | 2980 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 2981 | NULL); |
c1a2f7f0 | 2982 | |
6345d24d | 2983 | /* |
c1a2f7f0 RR |
2984 | * The mm_cpumask is located at the end of mm_struct, and is |
2985 | * dynamically sized based on the maximum CPU number this system | |
2986 | * can have, taking hotplug into account (nr_cpu_ids). | |
6345d24d | 2987 | */ |
c1a2f7f0 RR |
2988 | mm_size = sizeof(struct mm_struct) + cpumask_size(); |
2989 | ||
07dcd7fe | 2990 | mm_cachep = kmem_cache_create_usercopy("mm_struct", |
c1a2f7f0 | 2991 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN, |
75f296d9 | 2992 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
07dcd7fe DW |
2993 | offsetof(struct mm_struct, saved_auxv), |
2994 | sizeof_field(struct mm_struct, saved_auxv), | |
5d097056 VD |
2995 | NULL); |
2996 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 2997 | mmap_init(); |
66577193 | 2998 | nsproxy_cache_init(); |
1da177e4 | 2999 | } |
cf2e340f | 3000 | |
cf2e340f | 3001 | /* |
9bfb23fc | 3002 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 3003 | */ |
9bfb23fc | 3004 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 3005 | { |
9bfb23fc ON |
3006 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
3007 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 3008 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
769071ac AV |
3009 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP| |
3010 | CLONE_NEWTIME)) | |
9bfb23fc | 3011 | return -EINVAL; |
cf2e340f | 3012 | /* |
12c641ab EB |
3013 | * Not implemented, but pretend it works if there is nothing |
3014 | * to unshare. Note that unsharing the address space or the | |
3015 | * signal handlers also need to unshare the signal queues (aka | |
3016 | * CLONE_THREAD). | |
cf2e340f | 3017 | */ |
9bfb23fc | 3018 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
3019 | if (!thread_group_empty(current)) |
3020 | return -EINVAL; | |
3021 | } | |
3022 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
d036bda7 | 3023 | if (refcount_read(¤t->sighand->count) > 1) |
12c641ab EB |
3024 | return -EINVAL; |
3025 | } | |
3026 | if (unshare_flags & CLONE_VM) { | |
3027 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
3028 | return -EINVAL; |
3029 | } | |
cf2e340f JD |
3030 | |
3031 | return 0; | |
3032 | } | |
3033 | ||
3034 | /* | |
99d1419d | 3035 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
3036 | */ |
3037 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
3038 | { | |
3039 | struct fs_struct *fs = current->fs; | |
3040 | ||
498052bb AV |
3041 | if (!(unshare_flags & CLONE_FS) || !fs) |
3042 | return 0; | |
3043 | ||
3044 | /* don't need lock here; in the worst case we'll do useless copy */ | |
3045 | if (fs->users == 1) | |
3046 | return 0; | |
3047 | ||
3048 | *new_fsp = copy_fs_struct(fs); | |
3049 | if (!*new_fsp) | |
3050 | return -ENOMEM; | |
cf2e340f JD |
3051 | |
3052 | return 0; | |
3053 | } | |
3054 | ||
cf2e340f | 3055 | /* |
a016f338 | 3056 | * Unshare file descriptor table if it is being shared |
cf2e340f | 3057 | */ |
60997c3d CB |
3058 | int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
3059 | struct files_struct **new_fdp) | |
cf2e340f JD |
3060 | { |
3061 | struct files_struct *fd = current->files; | |
a016f338 | 3062 | int error = 0; |
cf2e340f JD |
3063 | |
3064 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 | 3065 | (fd && atomic_read(&fd->count) > 1)) { |
60997c3d | 3066 | *new_fdp = dup_fd(fd, max_fds, &error); |
a016f338 JD |
3067 | if (!*new_fdp) |
3068 | return error; | |
3069 | } | |
cf2e340f JD |
3070 | |
3071 | return 0; | |
3072 | } | |
3073 | ||
cf2e340f JD |
3074 | /* |
3075 | * unshare allows a process to 'unshare' part of the process | |
3076 | * context which was originally shared using clone. copy_* | |
cad6967a | 3077 | * functions used by kernel_clone() cannot be used here directly |
cf2e340f JD |
3078 | * because they modify an inactive task_struct that is being |
3079 | * constructed. Here we are modifying the current, active, | |
3080 | * task_struct. | |
3081 | */ | |
9b32105e | 3082 | int ksys_unshare(unsigned long unshare_flags) |
cf2e340f | 3083 | { |
cf2e340f | 3084 | struct fs_struct *fs, *new_fs = NULL; |
ba1f70dd | 3085 | struct files_struct *new_fd = NULL; |
b2e0d987 | 3086 | struct cred *new_cred = NULL; |
cf7b708c | 3087 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 3088 | int do_sysvsem = 0; |
9bfb23fc | 3089 | int err; |
cf2e340f | 3090 | |
b2e0d987 | 3091 | /* |
faf00da5 EB |
3092 | * If unsharing a user namespace must also unshare the thread group |
3093 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
3094 | */ |
3095 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 3096 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
3097 | /* |
3098 | * If unsharing vm, must also unshare signal handlers. | |
3099 | */ | |
3100 | if (unshare_flags & CLONE_VM) | |
3101 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
3102 | /* |
3103 | * If unsharing a signal handlers, must also unshare the signal queues. | |
3104 | */ | |
3105 | if (unshare_flags & CLONE_SIGHAND) | |
3106 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
3107 | /* |
3108 | * If unsharing namespace, must also unshare filesystem information. | |
3109 | */ | |
3110 | if (unshare_flags & CLONE_NEWNS) | |
3111 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
3112 | |
3113 | err = check_unshare_flags(unshare_flags); | |
3114 | if (err) | |
3115 | goto bad_unshare_out; | |
6013f67f MS |
3116 | /* |
3117 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
3118 | * to a new ipc namespace, the semaphore arrays from the old | |
3119 | * namespace are unreachable. | |
3120 | */ | |
3121 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 3122 | do_sysvsem = 1; |
fb0a685c DRO |
3123 | err = unshare_fs(unshare_flags, &new_fs); |
3124 | if (err) | |
9bfb23fc | 3125 | goto bad_unshare_out; |
60997c3d | 3126 | err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd); |
fb0a685c | 3127 | if (err) |
9bfb23fc | 3128 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 3129 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 3130 | if (err) |
9edff4ab | 3131 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
3132 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
3133 | new_cred, new_fs); | |
3134 | if (err) | |
3135 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 3136 | |
905ae01c AG |
3137 | if (new_cred) { |
3138 | err = set_cred_ucounts(new_cred); | |
3139 | if (err) | |
3140 | goto bad_unshare_cleanup_cred; | |
3141 | } | |
3142 | ||
b2e0d987 | 3143 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
3144 | if (do_sysvsem) { |
3145 | /* | |
3146 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
3147 | */ | |
3148 | exit_sem(current); | |
3149 | } | |
ab602f79 JM |
3150 | if (unshare_flags & CLONE_NEWIPC) { |
3151 | /* Orphan segments in old ns (see sem above). */ | |
3152 | exit_shm(current); | |
3153 | shm_init_task(current); | |
3154 | } | |
ab516013 | 3155 | |
6f977e6b | 3156 | if (new_nsproxy) |
cf7b708c | 3157 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 3158 | |
cf7b708c PE |
3159 | task_lock(current); |
3160 | ||
cf2e340f JD |
3161 | if (new_fs) { |
3162 | fs = current->fs; | |
2a4419b5 | 3163 | spin_lock(&fs->lock); |
cf2e340f | 3164 | current->fs = new_fs; |
498052bb AV |
3165 | if (--fs->users) |
3166 | new_fs = NULL; | |
3167 | else | |
3168 | new_fs = fs; | |
2a4419b5 | 3169 | spin_unlock(&fs->lock); |
cf2e340f JD |
3170 | } |
3171 | ||
ba1f70dd RX |
3172 | if (new_fd) |
3173 | swap(current->files, new_fd); | |
cf2e340f JD |
3174 | |
3175 | task_unlock(current); | |
b2e0d987 EB |
3176 | |
3177 | if (new_cred) { | |
3178 | /* Install the new user namespace */ | |
3179 | commit_creds(new_cred); | |
3180 | new_cred = NULL; | |
3181 | } | |
cf2e340f JD |
3182 | } |
3183 | ||
e4222673 HB |
3184 | perf_event_namespaces(current); |
3185 | ||
b2e0d987 EB |
3186 | bad_unshare_cleanup_cred: |
3187 | if (new_cred) | |
3188 | put_cred(new_cred); | |
cf2e340f JD |
3189 | bad_unshare_cleanup_fd: |
3190 | if (new_fd) | |
3191 | put_files_struct(new_fd); | |
3192 | ||
cf2e340f JD |
3193 | bad_unshare_cleanup_fs: |
3194 | if (new_fs) | |
498052bb | 3195 | free_fs_struct(new_fs); |
cf2e340f | 3196 | |
cf2e340f JD |
3197 | bad_unshare_out: |
3198 | return err; | |
3199 | } | |
3b125388 | 3200 | |
9b32105e DB |
3201 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
3202 | { | |
3203 | return ksys_unshare(unshare_flags); | |
3204 | } | |
3205 | ||
3b125388 AV |
3206 | /* |
3207 | * Helper to unshare the files of the current task. | |
3208 | * We don't want to expose copy_files internals to | |
3209 | * the exec layer of the kernel. | |
3210 | */ | |
3211 | ||
1f702603 | 3212 | int unshare_files(void) |
3b125388 AV |
3213 | { |
3214 | struct task_struct *task = current; | |
1f702603 | 3215 | struct files_struct *old, *copy = NULL; |
3b125388 AV |
3216 | int error; |
3217 | ||
60997c3d | 3218 | error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); |
1f702603 | 3219 | if (error || !copy) |
3b125388 | 3220 | return error; |
1f702603 EB |
3221 | |
3222 | old = task->files; | |
3b125388 AV |
3223 | task_lock(task); |
3224 | task->files = copy; | |
3225 | task_unlock(task); | |
1f702603 | 3226 | put_files_struct(old); |
3b125388 AV |
3227 | return 0; |
3228 | } | |
16db3d3f HS |
3229 | |
3230 | int sysctl_max_threads(struct ctl_table *table, int write, | |
b0daa2c7 | 3231 | void *buffer, size_t *lenp, loff_t *ppos) |
16db3d3f HS |
3232 | { |
3233 | struct ctl_table t; | |
3234 | int ret; | |
3235 | int threads = max_threads; | |
b0f53dbc | 3236 | int min = 1; |
16db3d3f HS |
3237 | int max = MAX_THREADS; |
3238 | ||
3239 | t = *table; | |
3240 | t.data = &threads; | |
3241 | t.extra1 = &min; | |
3242 | t.extra2 = &max; | |
3243 | ||
3244 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
3245 | if (ret || !write) | |
3246 | return ret; | |
3247 | ||
b0f53dbc | 3248 | max_threads = threads; |
16db3d3f HS |
3249 | |
3250 | return 0; | |
3251 | } |