Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/fork.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
9 | * 'fork.c' contains the help-routines for the 'fork' system call | |
10 | * (see also entry.S and others). | |
11 | * Fork is rather simple, once you get the hang of it, but the memory | |
12 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
13 | */ | |
14 | ||
b3e58382 | 15 | #include <linux/anon_inodes.h> |
1da177e4 | 16 | #include <linux/slab.h> |
4eb5aaa3 | 17 | #include <linux/sched/autogroup.h> |
6e84f315 | 18 | #include <linux/sched/mm.h> |
f7ccbae4 | 19 | #include <linux/sched/coredump.h> |
8703e8a4 | 20 | #include <linux/sched/user.h> |
6a3827d7 | 21 | #include <linux/sched/numa_balancing.h> |
03441a34 | 22 | #include <linux/sched/stat.h> |
29930025 | 23 | #include <linux/sched/task.h> |
68db0cf1 | 24 | #include <linux/sched/task_stack.h> |
32ef5517 | 25 | #include <linux/sched/cputime.h> |
b3e58382 | 26 | #include <linux/seq_file.h> |
037741a6 | 27 | #include <linux/rtmutex.h> |
1da177e4 LT |
28 | #include <linux/init.h> |
29 | #include <linux/unistd.h> | |
1da177e4 LT |
30 | #include <linux/module.h> |
31 | #include <linux/vmalloc.h> | |
32 | #include <linux/completion.h> | |
1da177e4 LT |
33 | #include <linux/personality.h> |
34 | #include <linux/mempolicy.h> | |
35 | #include <linux/sem.h> | |
36 | #include <linux/file.h> | |
9f3acc31 | 37 | #include <linux/fdtable.h> |
da9cbc87 | 38 | #include <linux/iocontext.h> |
1da177e4 | 39 | #include <linux/key.h> |
50b5e49c | 40 | #include <linux/kmsan.h> |
1da177e4 LT |
41 | #include <linux/binfmts.h> |
42 | #include <linux/mman.h> | |
cddb8a5c | 43 | #include <linux/mmu_notifier.h> |
1da177e4 | 44 | #include <linux/fs.h> |
615d6e87 | 45 | #include <linux/mm.h> |
17fca131 | 46 | #include <linux/mm_inline.h> |
ab516013 | 47 | #include <linux/nsproxy.h> |
c59ede7b | 48 | #include <linux/capability.h> |
1da177e4 | 49 | #include <linux/cpu.h> |
b4f48b63 | 50 | #include <linux/cgroup.h> |
1da177e4 | 51 | #include <linux/security.h> |
a1e78772 | 52 | #include <linux/hugetlb.h> |
e2cfabdf | 53 | #include <linux/seccomp.h> |
1da177e4 LT |
54 | #include <linux/swap.h> |
55 | #include <linux/syscalls.h> | |
56 | #include <linux/jiffies.h> | |
57 | #include <linux/futex.h> | |
8141c7f3 | 58 | #include <linux/compat.h> |
207205a2 | 59 | #include <linux/kthread.h> |
7c3ab738 | 60 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 61 | #include <linux/rcupdate.h> |
1da177e4 LT |
62 | #include <linux/ptrace.h> |
63 | #include <linux/mount.h> | |
64 | #include <linux/audit.h> | |
78fb7466 | 65 | #include <linux/memcontrol.h> |
f201ae23 | 66 | #include <linux/ftrace.h> |
5e2bf014 | 67 | #include <linux/proc_fs.h> |
1da177e4 LT |
68 | #include <linux/profile.h> |
69 | #include <linux/rmap.h> | |
f8af4da3 | 70 | #include <linux/ksm.h> |
1da177e4 | 71 | #include <linux/acct.h> |
893e26e6 | 72 | #include <linux/userfaultfd_k.h> |
8f0ab514 | 73 | #include <linux/tsacct_kern.h> |
9f46080c | 74 | #include <linux/cn_proc.h> |
ba96a0c8 | 75 | #include <linux/freezer.h> |
ca74e92b | 76 | #include <linux/delayacct.h> |
ad4ecbcb | 77 | #include <linux/taskstats_kern.h> |
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); |
5c26f6ac | 478 | dup_anon_vma_name(orig, new); |
95faf699 LT |
479 | } |
480 | return new; | |
3928d4f5 LT |
481 | } |
482 | ||
483 | void vm_area_free(struct vm_area_struct *vma) | |
484 | { | |
5c26f6ac | 485 | free_anon_vma_name(vma); |
3928d4f5 LT |
486 | kmem_cache_free(vm_area_cachep, vma); |
487 | } | |
488 | ||
ba14a194 | 489 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 490 | { |
0ce055f8 SAS |
491 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
492 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
27faca83 | 493 | int i; |
ba14a194 | 494 | |
27faca83 MS |
495 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) |
496 | mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB, | |
497 | account * (PAGE_SIZE / 1024)); | |
498 | } else { | |
0ce055f8 SAS |
499 | void *stack = task_stack_page(tsk); |
500 | ||
27faca83 | 501 | /* All stack pages are in the same node. */ |
da3ceeff | 502 | mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB, |
991e7673 | 503 | account * (THREAD_SIZE / 1024)); |
27faca83 | 504 | } |
c6a7f572 KM |
505 | } |
506 | ||
1a03d3f1 | 507 | void exit_task_stack_account(struct task_struct *tsk) |
9b6f7e16 | 508 | { |
1a03d3f1 | 509 | account_kernel_stack(tsk, -1); |
991e7673 | 510 | |
1a03d3f1 SAS |
511 | if (IS_ENABLED(CONFIG_VMAP_STACK)) { |
512 | struct vm_struct *vm; | |
9b6f7e16 RG |
513 | int i; |
514 | ||
1a03d3f1 SAS |
515 | vm = task_stack_vm_area(tsk); |
516 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) | |
517 | memcg_kmem_uncharge_page(vm->pages[i], 0); | |
9b6f7e16 | 518 | } |
9b6f7e16 RG |
519 | } |
520 | ||
68f24b08 | 521 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 522 | { |
2f064a59 | 523 | if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD)) |
405c0759 AL |
524 | return; /* Better to leak the stack than to free prematurely */ |
525 | ||
ba14a194 | 526 | free_thread_stack(tsk); |
68f24b08 AL |
527 | } |
528 | ||
529 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
530 | void put_task_stack(struct task_struct *tsk) | |
531 | { | |
f0b89d39 | 532 | if (refcount_dec_and_test(&tsk->stack_refcount)) |
68f24b08 AL |
533 | release_task_stack(tsk); |
534 | } | |
535 | #endif | |
536 | ||
537 | void free_task(struct task_struct *tsk) | |
538 | { | |
b90ca8ba | 539 | release_user_cpus_ptr(tsk); |
d08b9f0c ST |
540 | scs_release(tsk); |
541 | ||
68f24b08 AL |
542 | #ifndef CONFIG_THREAD_INFO_IN_TASK |
543 | /* | |
544 | * The task is finally done with both the stack and thread_info, | |
545 | * so free both. | |
546 | */ | |
547 | release_task_stack(tsk); | |
548 | #else | |
549 | /* | |
550 | * If the task had a separate stack allocation, it should be gone | |
551 | * by now. | |
552 | */ | |
f0b89d39 | 553 | WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0); |
68f24b08 | 554 | #endif |
23f78d4a | 555 | rt_mutex_debug_task_free(tsk); |
fb52607a | 556 | ftrace_graph_exit_task(tsk); |
f19b9f74 | 557 | arch_release_task_struct(tsk); |
1da5c46f ON |
558 | if (tsk->flags & PF_KTHREAD) |
559 | free_kthread_struct(tsk); | |
1da177e4 LT |
560 | free_task_struct(tsk); |
561 | } | |
562 | EXPORT_SYMBOL(free_task); | |
563 | ||
fe69d560 DH |
564 | static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm) |
565 | { | |
566 | struct file *exe_file; | |
567 | ||
568 | exe_file = get_mm_exe_file(oldmm); | |
569 | RCU_INIT_POINTER(mm->exe_file, exe_file); | |
570 | /* | |
571 | * We depend on the oldmm having properly denied write access to the | |
572 | * exe_file already. | |
573 | */ | |
574 | if (exe_file && deny_write_access(exe_file)) | |
575 | pr_warn_once("deny_write_access() failed in %s\n", __func__); | |
576 | } | |
577 | ||
d70f2a14 AM |
578 | #ifdef CONFIG_MMU |
579 | static __latent_entropy int dup_mmap(struct mm_struct *mm, | |
580 | struct mm_struct *oldmm) | |
581 | { | |
763ecb03 | 582 | struct vm_area_struct *mpnt, *tmp; |
d70f2a14 | 583 | int retval; |
c9dbe82c | 584 | unsigned long charge = 0; |
d70f2a14 | 585 | LIST_HEAD(uf); |
c9dbe82c | 586 | MA_STATE(old_mas, &oldmm->mm_mt, 0, 0); |
d4af56c5 | 587 | MA_STATE(mas, &mm->mm_mt, 0, 0); |
d70f2a14 AM |
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 | ||
d70f2a14 AM |
609 | retval = ksm_fork(mm, oldmm); |
610 | if (retval) | |
611 | goto out; | |
d2081b2b | 612 | khugepaged_fork(mm, oldmm); |
d70f2a14 | 613 | |
c9dbe82c LH |
614 | retval = mas_expected_entries(&mas, oldmm->map_count); |
615 | if (retval) | |
616 | goto out; | |
617 | ||
618 | mas_for_each(&old_mas, mpnt, ULONG_MAX) { | |
d70f2a14 AM |
619 | struct file *file; |
620 | ||
621 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
622 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); | |
623 | continue; | |
624 | } | |
625 | charge = 0; | |
655c79bb TH |
626 | /* |
627 | * Don't duplicate many vmas if we've been oom-killed (for | |
628 | * example) | |
629 | */ | |
630 | if (fatal_signal_pending(current)) { | |
631 | retval = -EINTR; | |
d4af56c5 | 632 | goto loop_out; |
655c79bb | 633 | } |
d70f2a14 AM |
634 | if (mpnt->vm_flags & VM_ACCOUNT) { |
635 | unsigned long len = vma_pages(mpnt); | |
636 | ||
637 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ | |
638 | goto fail_nomem; | |
639 | charge = len; | |
640 | } | |
3928d4f5 | 641 | tmp = vm_area_dup(mpnt); |
d70f2a14 AM |
642 | if (!tmp) |
643 | goto fail_nomem; | |
d70f2a14 AM |
644 | retval = vma_dup_policy(mpnt, tmp); |
645 | if (retval) | |
646 | goto fail_nomem_policy; | |
647 | tmp->vm_mm = mm; | |
648 | retval = dup_userfaultfd(tmp, &uf); | |
649 | if (retval) | |
650 | goto fail_nomem_anon_vma_fork; | |
651 | if (tmp->vm_flags & VM_WIPEONFORK) { | |
93949bb2 LX |
652 | /* |
653 | * VM_WIPEONFORK gets a clean slate in the child. | |
654 | * Don't prepare anon_vma until fault since we don't | |
655 | * copy page for current vma. | |
656 | */ | |
d70f2a14 | 657 | tmp->anon_vma = NULL; |
d70f2a14 AM |
658 | } else if (anon_vma_fork(tmp, mpnt)) |
659 | goto fail_nomem_anon_vma_fork; | |
660 | tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); | |
d70f2a14 AM |
661 | file = tmp->vm_file; |
662 | if (file) { | |
d70f2a14 AM |
663 | struct address_space *mapping = file->f_mapping; |
664 | ||
665 | get_file(file); | |
d70f2a14 AM |
666 | i_mmap_lock_write(mapping); |
667 | if (tmp->vm_flags & VM_SHARED) | |
cf508b58 | 668 | mapping_allow_writable(mapping); |
d70f2a14 AM |
669 | flush_dcache_mmap_lock(mapping); |
670 | /* insert tmp into the share list, just after mpnt */ | |
671 | vma_interval_tree_insert_after(tmp, mpnt, | |
672 | &mapping->i_mmap); | |
673 | flush_dcache_mmap_unlock(mapping); | |
674 | i_mmap_unlock_write(mapping); | |
675 | } | |
676 | ||
677 | /* | |
8d9bfb26 | 678 | * Copy/update hugetlb private vma information. |
d70f2a14 AM |
679 | */ |
680 | if (is_vm_hugetlb_page(tmp)) | |
8d9bfb26 | 681 | hugetlb_dup_vma_private(tmp); |
d70f2a14 | 682 | |
d4af56c5 LH |
683 | /* Link the vma into the MT */ |
684 | mas.index = tmp->vm_start; | |
685 | mas.last = tmp->vm_end - 1; | |
686 | mas_store(&mas, tmp); | |
c9dbe82c LH |
687 | if (mas_is_err(&mas)) |
688 | goto fail_nomem_mas_store; | |
d4af56c5 | 689 | |
d70f2a14 AM |
690 | mm->map_count++; |
691 | if (!(tmp->vm_flags & VM_WIPEONFORK)) | |
c78f4636 | 692 | retval = copy_page_range(tmp, mpnt); |
d70f2a14 AM |
693 | |
694 | if (tmp->vm_ops && tmp->vm_ops->open) | |
695 | tmp->vm_ops->open(tmp); | |
696 | ||
697 | if (retval) | |
d4af56c5 | 698 | goto loop_out; |
d70f2a14 AM |
699 | } |
700 | /* a new mm has just been created */ | |
1ed0cc5a | 701 | retval = arch_dup_mmap(oldmm, mm); |
d4af56c5 LH |
702 | loop_out: |
703 | mas_destroy(&mas); | |
d70f2a14 | 704 | out: |
d8ed45c5 | 705 | mmap_write_unlock(mm); |
d70f2a14 | 706 | flush_tlb_mm(oldmm); |
d8ed45c5 | 707 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
708 | dup_userfaultfd_complete(&uf); |
709 | fail_uprobe_end: | |
710 | uprobe_end_dup_mmap(); | |
711 | return retval; | |
c9dbe82c LH |
712 | |
713 | fail_nomem_mas_store: | |
714 | unlink_anon_vmas(tmp); | |
d70f2a14 AM |
715 | fail_nomem_anon_vma_fork: |
716 | mpol_put(vma_policy(tmp)); | |
717 | fail_nomem_policy: | |
3928d4f5 | 718 | vm_area_free(tmp); |
d70f2a14 AM |
719 | fail_nomem: |
720 | retval = -ENOMEM; | |
721 | vm_unacct_memory(charge); | |
d4af56c5 | 722 | goto loop_out; |
d70f2a14 AM |
723 | } |
724 | ||
725 | static inline int mm_alloc_pgd(struct mm_struct *mm) | |
726 | { | |
727 | mm->pgd = pgd_alloc(mm); | |
728 | if (unlikely(!mm->pgd)) | |
729 | return -ENOMEM; | |
730 | return 0; | |
731 | } | |
732 | ||
733 | static inline void mm_free_pgd(struct mm_struct *mm) | |
734 | { | |
735 | pgd_free(mm, mm->pgd); | |
736 | } | |
737 | #else | |
738 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) | |
739 | { | |
d8ed45c5 | 740 | mmap_write_lock(oldmm); |
fe69d560 | 741 | dup_mm_exe_file(mm, oldmm); |
d8ed45c5 | 742 | mmap_write_unlock(oldmm); |
d70f2a14 AM |
743 | return 0; |
744 | } | |
745 | #define mm_alloc_pgd(mm) (0) | |
746 | #define mm_free_pgd(mm) | |
747 | #endif /* CONFIG_MMU */ | |
748 | ||
749 | static void check_mm(struct mm_struct *mm) | |
750 | { | |
751 | int i; | |
752 | ||
8495f7e6 SPP |
753 | BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS, |
754 | "Please make sure 'struct resident_page_types[]' is updated as well"); | |
755 | ||
d70f2a14 AM |
756 | for (i = 0; i < NR_MM_COUNTERS; i++) { |
757 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
758 | ||
759 | if (unlikely(x)) | |
8495f7e6 SPP |
760 | pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n", |
761 | mm, resident_page_types[i], x); | |
d70f2a14 AM |
762 | } |
763 | ||
764 | if (mm_pgtables_bytes(mm)) | |
765 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", | |
766 | mm_pgtables_bytes(mm)); | |
767 | ||
768 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
769 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); | |
770 | #endif | |
771 | } | |
772 | ||
773 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) | |
774 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
775 | ||
776 | /* | |
777 | * Called when the last reference to the mm | |
778 | * is dropped: either by a lazy thread or by | |
779 | * mmput. Free the page directory and the mm. | |
780 | */ | |
d34bc48f | 781 | void __mmdrop(struct mm_struct *mm) |
d70f2a14 AM |
782 | { |
783 | BUG_ON(mm == &init_mm); | |
3eda69c9 MR |
784 | WARN_ON_ONCE(mm == current->mm); |
785 | WARN_ON_ONCE(mm == current->active_mm); | |
d70f2a14 AM |
786 | mm_free_pgd(mm); |
787 | destroy_context(mm); | |
984cfe4e | 788 | mmu_notifier_subscriptions_destroy(mm); |
d70f2a14 AM |
789 | check_mm(mm); |
790 | put_user_ns(mm->user_ns); | |
2667ed10 | 791 | mm_pasid_drop(mm); |
d70f2a14 AM |
792 | free_mm(mm); |
793 | } | |
d34bc48f | 794 | EXPORT_SYMBOL_GPL(__mmdrop); |
d70f2a14 AM |
795 | |
796 | static void mmdrop_async_fn(struct work_struct *work) | |
797 | { | |
798 | struct mm_struct *mm; | |
799 | ||
800 | mm = container_of(work, struct mm_struct, async_put_work); | |
801 | __mmdrop(mm); | |
802 | } | |
803 | ||
804 | static void mmdrop_async(struct mm_struct *mm) | |
805 | { | |
806 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) { | |
807 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn); | |
808 | schedule_work(&mm->async_put_work); | |
809 | } | |
810 | } | |
811 | ||
ea6d290c ON |
812 | static inline void free_signal_struct(struct signal_struct *sig) |
813 | { | |
97101eb4 | 814 | taskstats_tgid_free(sig); |
1c5354de | 815 | sched_autogroup_exit(sig); |
7283094e MH |
816 | /* |
817 | * __mmdrop is not safe to call from softirq context on x86 due to | |
818 | * pgd_dtor so postpone it to the async context | |
819 | */ | |
26db62f1 | 820 | if (sig->oom_mm) |
7283094e | 821 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
822 | kmem_cache_free(signal_cachep, sig); |
823 | } | |
824 | ||
825 | static inline void put_signal_struct(struct signal_struct *sig) | |
826 | { | |
60d4de3f | 827 | if (refcount_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
828 | free_signal_struct(sig); |
829 | } | |
830 | ||
158d9ebd | 831 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 832 | { |
270f722d | 833 | WARN_ON(!tsk->exit_state); |
ec1d2819 | 834 | WARN_ON(refcount_read(&tsk->usage)); |
1da177e4 LT |
835 | WARN_ON(tsk == current); |
836 | ||
0f212204 | 837 | io_uring_free(tsk); |
2e91fa7f | 838 | cgroup_free(tsk); |
16d51a59 | 839 | task_numa_free(tsk, true); |
1a2a4d06 | 840 | security_task_free(tsk); |
a10787e6 | 841 | bpf_task_storage_free(tsk); |
e0e81739 | 842 | exit_creds(tsk); |
35df17c5 | 843 | delayacct_tsk_free(tsk); |
ea6d290c | 844 | put_signal_struct(tsk->signal); |
6e33cad0 | 845 | sched_core_free(tsk); |
2873cd31 | 846 | free_task(tsk); |
1da177e4 | 847 | } |
77c100c8 | 848 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 849 | |
6c0a9fa6 | 850 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 851 | |
ff691f6e HS |
852 | /* |
853 | * set_max_threads | |
854 | */ | |
16db3d3f | 855 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 856 | { |
ac1b398d | 857 | u64 threads; |
ca79b0c2 | 858 | unsigned long nr_pages = totalram_pages(); |
ff691f6e HS |
859 | |
860 | /* | |
ac1b398d HS |
861 | * The number of threads shall be limited such that the thread |
862 | * structures may only consume a small part of the available memory. | |
ff691f6e | 863 | */ |
3d6357de | 864 | if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64) |
ac1b398d HS |
865 | threads = MAX_THREADS; |
866 | else | |
3d6357de | 867 | threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE, |
ac1b398d HS |
868 | (u64) THREAD_SIZE * 8UL); |
869 | ||
16db3d3f HS |
870 | if (threads > max_threads_suggested) |
871 | threads = max_threads_suggested; | |
872 | ||
ac1b398d | 873 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
874 | } |
875 | ||
5aaeb5c0 IM |
876 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
877 | /* Initialized by the architecture: */ | |
878 | int arch_task_struct_size __read_mostly; | |
879 | #endif | |
0c8c0f03 | 880 | |
4189ff23 | 881 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
5905429a KC |
882 | static void task_struct_whitelist(unsigned long *offset, unsigned long *size) |
883 | { | |
884 | /* Fetch thread_struct whitelist for the architecture. */ | |
885 | arch_thread_struct_whitelist(offset, size); | |
886 | ||
887 | /* | |
888 | * Handle zero-sized whitelist or empty thread_struct, otherwise | |
889 | * adjust offset to position of thread_struct in task_struct. | |
890 | */ | |
891 | if (unlikely(*size == 0)) | |
892 | *offset = 0; | |
893 | else | |
894 | *offset += offsetof(struct task_struct, thread); | |
895 | } | |
4189ff23 | 896 | #endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */ |
5905429a | 897 | |
ff691f6e | 898 | void __init fork_init(void) |
1da177e4 | 899 | { |
25f9c081 | 900 | int i; |
f5e10287 | 901 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 902 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 903 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 904 | #endif |
95cb64c1 | 905 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
5905429a | 906 | unsigned long useroffset, usersize; |
e274795e | 907 | |
1da177e4 | 908 | /* create a slab on which task_structs can be allocated */ |
5905429a KC |
909 | task_struct_whitelist(&useroffset, &usersize); |
910 | task_struct_cachep = kmem_cache_create_usercopy("task_struct", | |
e274795e | 911 | arch_task_struct_size, align, |
5905429a KC |
912 | SLAB_PANIC|SLAB_ACCOUNT, |
913 | useroffset, usersize, NULL); | |
1da177e4 LT |
914 | #endif |
915 | ||
61c4628b SS |
916 | /* do the arch specific task caches init */ |
917 | arch_task_cache_init(); | |
918 | ||
16db3d3f | 919 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
920 | |
921 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
922 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
923 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
924 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 925 | |
21d1c5e3 | 926 | for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) |
25f9c081 | 927 | init_user_ns.ucount_max[i] = max_threads/2; |
19659c59 | 928 | |
5ddf994f EB |
929 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); |
930 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); | |
931 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); | |
932 | set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); | |
21d1c5e3 | 933 | |
19659c59 HR |
934 | #ifdef CONFIG_VMAP_STACK |
935 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", | |
936 | NULL, free_vm_stack_cache); | |
937 | #endif | |
b09be676 | 938 | |
d08b9f0c ST |
939 | scs_init(); |
940 | ||
b09be676 | 941 | lockdep_init_task(&init_task); |
aad42dd4 | 942 | uprobes_init(); |
1da177e4 LT |
943 | } |
944 | ||
52f5684c | 945 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
946 | struct task_struct *src) |
947 | { | |
948 | *dst = *src; | |
949 | return 0; | |
950 | } | |
951 | ||
d4311ff1 AT |
952 | void set_task_stack_end_magic(struct task_struct *tsk) |
953 | { | |
954 | unsigned long *stackend; | |
955 | ||
956 | stackend = end_of_stack(tsk); | |
957 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
958 | } | |
959 | ||
725fc629 | 960 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
961 | { |
962 | struct task_struct *tsk; | |
3e26c149 | 963 | int err; |
1da177e4 | 964 | |
725fc629 AK |
965 | if (node == NUMA_NO_NODE) |
966 | node = tsk_fork_get_node(orig); | |
504f52b5 | 967 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
968 | if (!tsk) |
969 | return NULL; | |
970 | ||
546c42b2 SAS |
971 | err = arch_dup_task_struct(tsk, orig); |
972 | if (err) | |
f19b9f74 | 973 | goto free_tsk; |
1da177e4 | 974 | |
7865aba3 SAS |
975 | err = alloc_thread_stack_node(tsk, node); |
976 | if (err) | |
f19b9f74 | 977 | goto free_tsk; |
ba14a194 | 978 | |
68f24b08 | 979 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
f0b89d39 | 980 | refcount_set(&tsk->stack_refcount, 1); |
68f24b08 | 981 | #endif |
1a03d3f1 | 982 | account_kernel_stack(tsk, 1); |
164c33c6 | 983 | |
d08b9f0c ST |
984 | err = scs_prepare(tsk, node); |
985 | if (err) | |
986 | goto free_stack; | |
987 | ||
dbd95212 KC |
988 | #ifdef CONFIG_SECCOMP |
989 | /* | |
990 | * We must handle setting up seccomp filters once we're under | |
991 | * the sighand lock in case orig has changed between now and | |
992 | * then. Until then, filter must be NULL to avoid messing up | |
993 | * the usage counts on the error path calling free_task. | |
994 | */ | |
995 | tsk->seccomp.filter = NULL; | |
996 | #endif | |
87bec58a AM |
997 | |
998 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 999 | clear_user_return_notifier(tsk); |
f26f9aff | 1000 | clear_tsk_need_resched(tsk); |
d4311ff1 | 1001 | set_task_stack_end_magic(tsk); |
1446e1df | 1002 | clear_syscall_work_syscall_user_dispatch(tsk); |
1da177e4 | 1003 | |
050e9baa | 1004 | #ifdef CONFIG_STACKPROTECTOR |
7cd815bc | 1005 | tsk->stack_canary = get_random_canary(); |
0a425405 | 1006 | #endif |
3bd37062 SAS |
1007 | if (orig->cpus_ptr == &orig->cpus_mask) |
1008 | tsk->cpus_ptr = &tsk->cpus_mask; | |
b90ca8ba | 1009 | dup_user_cpus_ptr(tsk, orig, node); |
0a425405 | 1010 | |
fb0a685c | 1011 | /* |
0ff7b2cf EB |
1012 | * One for the user space visible state that goes away when reaped. |
1013 | * One for the scheduler. | |
fb0a685c | 1014 | */ |
0ff7b2cf EB |
1015 | refcount_set(&tsk->rcu_users, 2); |
1016 | /* One for the rcu users */ | |
1017 | refcount_set(&tsk->usage, 1); | |
6c5c9341 | 1018 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 1019 | tsk->btrace_seq = 0; |
6c5c9341 | 1020 | #endif |
a0aa7f68 | 1021 | tsk->splice_pipe = NULL; |
5640f768 | 1022 | tsk->task_frag.page = NULL; |
093e5840 | 1023 | tsk->wake_q.next = NULL; |
e32cf5df | 1024 | tsk->worker_private = NULL; |
c6a7f572 | 1025 | |
5c9a8750 | 1026 | kcov_task_init(tsk); |
50b5e49c | 1027 | kmsan_task_create(tsk); |
5fbda3ec | 1028 | kmap_local_fork(tsk); |
5c9a8750 | 1029 | |
e41d5818 DV |
1030 | #ifdef CONFIG_FAULT_INJECTION |
1031 | tsk->fail_nth = 0; | |
1032 | #endif | |
1033 | ||
2c323017 JB |
1034 | #ifdef CONFIG_BLK_CGROUP |
1035 | tsk->throttle_queue = NULL; | |
1036 | tsk->use_memdelay = 0; | |
1037 | #endif | |
1038 | ||
a3d29e82 PZ |
1039 | #ifdef CONFIG_IOMMU_SVA |
1040 | tsk->pasid_activated = 0; | |
1041 | #endif | |
1042 | ||
d46eb14b SB |
1043 | #ifdef CONFIG_MEMCG |
1044 | tsk->active_memcg = NULL; | |
1045 | #endif | |
b041b525 TL |
1046 | |
1047 | #ifdef CONFIG_CPU_SUP_INTEL | |
1048 | tsk->reported_split_lock = 0; | |
1049 | #endif | |
1050 | ||
1da177e4 | 1051 | return tsk; |
61c4628b | 1052 | |
b235beea | 1053 | free_stack: |
1a03d3f1 | 1054 | exit_task_stack_account(tsk); |
ba14a194 | 1055 | free_thread_stack(tsk); |
f19b9f74 | 1056 | free_tsk: |
61c4628b SS |
1057 | free_task_struct(tsk); |
1058 | return NULL; | |
1da177e4 LT |
1059 | } |
1060 | ||
23ff4440 | 1061 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 1062 | |
4cb0e11b HK |
1063 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
1064 | ||
1065 | static int __init coredump_filter_setup(char *s) | |
1066 | { | |
1067 | default_dump_filter = | |
1068 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
1069 | MMF_DUMP_FILTER_MASK; | |
1070 | return 1; | |
1071 | } | |
1072 | ||
1073 | __setup("coredump_filter=", coredump_filter_setup); | |
1074 | ||
1da177e4 LT |
1075 | #include <linux/init_task.h> |
1076 | ||
858f0993 AD |
1077 | static void mm_init_aio(struct mm_struct *mm) |
1078 | { | |
1079 | #ifdef CONFIG_AIO | |
1080 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 1081 | mm->ioctx_table = NULL; |
858f0993 AD |
1082 | #endif |
1083 | } | |
1084 | ||
c3f3ce04 AA |
1085 | static __always_inline void mm_clear_owner(struct mm_struct *mm, |
1086 | struct task_struct *p) | |
1087 | { | |
1088 | #ifdef CONFIG_MEMCG | |
1089 | if (mm->owner == p) | |
1090 | WRITE_ONCE(mm->owner, NULL); | |
1091 | #endif | |
1092 | } | |
1093 | ||
33144e84 VD |
1094 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
1095 | { | |
1096 | #ifdef CONFIG_MEMCG | |
1097 | mm->owner = p; | |
1098 | #endif | |
1099 | } | |
1100 | ||
355627f5 EB |
1101 | static void mm_init_uprobes_state(struct mm_struct *mm) |
1102 | { | |
1103 | #ifdef CONFIG_UPROBES | |
1104 | mm->uprobes_state.xol_area = NULL; | |
1105 | #endif | |
1106 | } | |
1107 | ||
bfedb589 EB |
1108 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
1109 | struct user_namespace *user_ns) | |
1da177e4 | 1110 | { |
d4af56c5 LH |
1111 | mt_init_flags(&mm->mm_mt, MM_MT_FLAGS); |
1112 | mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock); | |
1da177e4 LT |
1113 | atomic_set(&mm->mm_users, 1); |
1114 | atomic_set(&mm->mm_count, 1); | |
57efa1fe | 1115 | seqcount_init(&mm->write_protect_seq); |
d8ed45c5 | 1116 | mmap_init_lock(mm); |
1da177e4 | 1117 | INIT_LIST_HEAD(&mm->mmlist); |
af5b0f6a | 1118 | mm_pgtables_bytes_init(mm); |
41f727fd VD |
1119 | mm->map_count = 0; |
1120 | mm->locked_vm = 0; | |
70f8a3ca | 1121 | atomic64_set(&mm->pinned_vm, 0); |
d559db08 | 1122 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 1123 | spin_lock_init(&mm->page_table_lock); |
88aa7cc6 | 1124 | spin_lock_init(&mm->arg_lock); |
41f727fd | 1125 | mm_init_cpumask(mm); |
858f0993 | 1126 | mm_init_aio(mm); |
cf475ad2 | 1127 | mm_init_owner(mm, p); |
a6cbd440 | 1128 | mm_pasid_init(mm); |
2b7e8665 | 1129 | RCU_INIT_POINTER(mm->exe_file, NULL); |
984cfe4e | 1130 | mmu_notifier_subscriptions_init(mm); |
16af97dc | 1131 | init_tlb_flush_pending(mm); |
41f727fd VD |
1132 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
1133 | mm->pmd_huge_pte = NULL; | |
1134 | #endif | |
355627f5 | 1135 | mm_init_uprobes_state(mm); |
13db8c50 | 1136 | hugetlb_count_init(mm); |
1da177e4 | 1137 | |
a0715cc2 AT |
1138 | if (current->mm) { |
1139 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
1140 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
1141 | } else { | |
1142 | mm->flags = default_dump_filter; | |
1da177e4 | 1143 | mm->def_flags = 0; |
a0715cc2 AT |
1144 | } |
1145 | ||
41f727fd VD |
1146 | if (mm_alloc_pgd(mm)) |
1147 | goto fail_nopgd; | |
1148 | ||
1149 | if (init_new_context(p, mm)) | |
1150 | goto fail_nocontext; | |
78fb7466 | 1151 | |
bfedb589 | 1152 | mm->user_ns = get_user_ns(user_ns); |
bd74fdae | 1153 | lru_gen_init_mm(mm); |
41f727fd VD |
1154 | return mm; |
1155 | ||
1156 | fail_nocontext: | |
1157 | mm_free_pgd(mm); | |
1158 | fail_nopgd: | |
1da177e4 LT |
1159 | free_mm(mm); |
1160 | return NULL; | |
1161 | } | |
1162 | ||
1163 | /* | |
1164 | * Allocate and initialize an mm_struct. | |
1165 | */ | |
fb0a685c | 1166 | struct mm_struct *mm_alloc(void) |
1da177e4 | 1167 | { |
fb0a685c | 1168 | struct mm_struct *mm; |
1da177e4 LT |
1169 | |
1170 | mm = allocate_mm(); | |
de03c72c KM |
1171 | if (!mm) |
1172 | return NULL; | |
1173 | ||
1174 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 1175 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
1176 | } |
1177 | ||
ec8d7c14 MH |
1178 | static inline void __mmput(struct mm_struct *mm) |
1179 | { | |
1180 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
1181 | ||
1182 | uprobe_clear_state(mm); | |
1183 | exit_aio(mm); | |
1184 | ksm_exit(mm); | |
1185 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
1186 | exit_mmap(mm); | |
6fcb52a5 | 1187 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
1188 | set_mm_exe_file(mm, NULL); |
1189 | if (!list_empty(&mm->mmlist)) { | |
1190 | spin_lock(&mmlist_lock); | |
1191 | list_del(&mm->mmlist); | |
1192 | spin_unlock(&mmlist_lock); | |
1193 | } | |
1194 | if (mm->binfmt) | |
1195 | module_put(mm->binfmt->module); | |
bd74fdae | 1196 | lru_gen_del_mm(mm); |
ec8d7c14 MH |
1197 | mmdrop(mm); |
1198 | } | |
1199 | ||
1da177e4 LT |
1200 | /* |
1201 | * Decrement the use count and release all resources for an mm. | |
1202 | */ | |
1203 | void mmput(struct mm_struct *mm) | |
1204 | { | |
0ae26f1b AM |
1205 | might_sleep(); |
1206 | ||
ec8d7c14 MH |
1207 | if (atomic_dec_and_test(&mm->mm_users)) |
1208 | __mmput(mm); | |
1209 | } | |
1210 | EXPORT_SYMBOL_GPL(mmput); | |
1211 | ||
a1b2289c SY |
1212 | #ifdef CONFIG_MMU |
1213 | static void mmput_async_fn(struct work_struct *work) | |
1214 | { | |
1215 | struct mm_struct *mm = container_of(work, struct mm_struct, | |
1216 | async_put_work); | |
1217 | ||
1218 | __mmput(mm); | |
1219 | } | |
1220 | ||
1221 | void mmput_async(struct mm_struct *mm) | |
1222 | { | |
1223 | if (atomic_dec_and_test(&mm->mm_users)) { | |
1224 | INIT_WORK(&mm->async_put_work, mmput_async_fn); | |
1225 | schedule_work(&mm->async_put_work); | |
1226 | } | |
1227 | } | |
1228 | #endif | |
1229 | ||
90f31d0e KK |
1230 | /** |
1231 | * set_mm_exe_file - change a reference to the mm's executable file | |
1232 | * | |
1233 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
1234 | * | |
6e399cd1 DB |
1235 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
1236 | * invocations: in mmput() nobody alive left, in execve task is single | |
35d7bdc8 | 1237 | * threaded. |
fe69d560 DH |
1238 | * |
1239 | * Can only fail if new_exe_file != NULL. | |
90f31d0e | 1240 | */ |
fe69d560 | 1241 | int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
38646013 | 1242 | { |
6e399cd1 DB |
1243 | struct file *old_exe_file; |
1244 | ||
1245 | /* | |
1246 | * It is safe to dereference the exe_file without RCU as | |
1247 | * this function is only called if nobody else can access | |
1248 | * this mm -- see comment above for justification. | |
1249 | */ | |
1250 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 1251 | |
fe69d560 DH |
1252 | if (new_exe_file) { |
1253 | /* | |
1254 | * We expect the caller (i.e., sys_execve) to already denied | |
1255 | * write access, so this is unlikely to fail. | |
1256 | */ | |
1257 | if (unlikely(deny_write_access(new_exe_file))) | |
1258 | return -EACCES; | |
38646013 | 1259 | get_file(new_exe_file); |
fe69d560 | 1260 | } |
90f31d0e | 1261 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
fe69d560 DH |
1262 | if (old_exe_file) { |
1263 | allow_write_access(old_exe_file); | |
90f31d0e | 1264 | fput(old_exe_file); |
fe69d560 DH |
1265 | } |
1266 | return 0; | |
38646013 JS |
1267 | } |
1268 | ||
35d7bdc8 DH |
1269 | /** |
1270 | * replace_mm_exe_file - replace a reference to the mm's executable file | |
1271 | * | |
1272 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe), | |
1273 | * dealing with concurrent invocation and without grabbing the mmap lock in | |
1274 | * write mode. | |
1275 | * | |
1276 | * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE). | |
1277 | */ | |
1278 | int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) | |
1279 | { | |
1280 | struct vm_area_struct *vma; | |
1281 | struct file *old_exe_file; | |
1282 | int ret = 0; | |
1283 | ||
1284 | /* Forbid mm->exe_file change if old file still mapped. */ | |
1285 | old_exe_file = get_mm_exe_file(mm); | |
1286 | if (old_exe_file) { | |
fa5e5876 | 1287 | VMA_ITERATOR(vmi, mm, 0); |
35d7bdc8 | 1288 | mmap_read_lock(mm); |
fa5e5876 | 1289 | for_each_vma(vmi, vma) { |
35d7bdc8 DH |
1290 | if (!vma->vm_file) |
1291 | continue; | |
1292 | if (path_equal(&vma->vm_file->f_path, | |
fa5e5876 | 1293 | &old_exe_file->f_path)) { |
35d7bdc8 | 1294 | ret = -EBUSY; |
fa5e5876 MWO |
1295 | break; |
1296 | } | |
35d7bdc8 DH |
1297 | } |
1298 | mmap_read_unlock(mm); | |
1299 | fput(old_exe_file); | |
1300 | if (ret) | |
1301 | return ret; | |
1302 | } | |
1303 | ||
1304 | /* set the new file, lockless */ | |
fe69d560 DH |
1305 | ret = deny_write_access(new_exe_file); |
1306 | if (ret) | |
1307 | return -EACCES; | |
35d7bdc8 | 1308 | get_file(new_exe_file); |
fe69d560 | 1309 | |
35d7bdc8 | 1310 | old_exe_file = xchg(&mm->exe_file, new_exe_file); |
fe69d560 DH |
1311 | if (old_exe_file) { |
1312 | /* | |
1313 | * Don't race with dup_mmap() getting the file and disallowing | |
1314 | * write access while someone might open the file writable. | |
1315 | */ | |
1316 | mmap_read_lock(mm); | |
1317 | allow_write_access(old_exe_file); | |
35d7bdc8 | 1318 | fput(old_exe_file); |
fe69d560 DH |
1319 | mmap_read_unlock(mm); |
1320 | } | |
35d7bdc8 | 1321 | return 0; |
38646013 JS |
1322 | } |
1323 | ||
90f31d0e KK |
1324 | /** |
1325 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
1326 | * | |
1327 | * Returns %NULL if mm has no associated executable file. | |
1328 | * User must release file via fput(). | |
1329 | */ | |
38646013 JS |
1330 | struct file *get_mm_exe_file(struct mm_struct *mm) |
1331 | { | |
1332 | struct file *exe_file; | |
1333 | ||
90f31d0e KK |
1334 | rcu_read_lock(); |
1335 | exe_file = rcu_dereference(mm->exe_file); | |
1336 | if (exe_file && !get_file_rcu(exe_file)) | |
1337 | exe_file = NULL; | |
1338 | rcu_read_unlock(); | |
38646013 JS |
1339 | return exe_file; |
1340 | } | |
1341 | ||
cd81a917 MG |
1342 | /** |
1343 | * get_task_exe_file - acquire a reference to the task's executable file | |
1344 | * | |
1345 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
1346 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
1347 | * User must release file via fput(). | |
1348 | */ | |
1349 | struct file *get_task_exe_file(struct task_struct *task) | |
1350 | { | |
1351 | struct file *exe_file = NULL; | |
1352 | struct mm_struct *mm; | |
1353 | ||
1354 | task_lock(task); | |
1355 | mm = task->mm; | |
1356 | if (mm) { | |
1357 | if (!(task->flags & PF_KTHREAD)) | |
1358 | exe_file = get_mm_exe_file(mm); | |
1359 | } | |
1360 | task_unlock(task); | |
1361 | return exe_file; | |
1362 | } | |
38646013 | 1363 | |
1da177e4 LT |
1364 | /** |
1365 | * get_task_mm - acquire a reference to the task's mm | |
1366 | * | |
246bb0b1 | 1367 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
1368 | * this kernel workthread has transiently adopted a user mm with use_mm, |
1369 | * to do its AIO) is not set and if so returns a reference to it, after | |
1370 | * bumping up the use count. User must release the mm via mmput() | |
1371 | * after use. Typically used by /proc and ptrace. | |
1372 | */ | |
1373 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1374 | { | |
1375 | struct mm_struct *mm; | |
1376 | ||
1377 | task_lock(task); | |
1378 | mm = task->mm; | |
1379 | if (mm) { | |
246bb0b1 | 1380 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1381 | mm = NULL; |
1382 | else | |
3fce371b | 1383 | mmget(mm); |
1da177e4 LT |
1384 | } |
1385 | task_unlock(task); | |
1386 | return mm; | |
1387 | } | |
1388 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1389 | ||
8cdb878d CY |
1390 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1391 | { | |
1392 | struct mm_struct *mm; | |
1393 | int err; | |
1394 | ||
f7cfd871 | 1395 | err = down_read_killable(&task->signal->exec_update_lock); |
8cdb878d CY |
1396 | if (err) |
1397 | return ERR_PTR(err); | |
1398 | ||
1399 | mm = get_task_mm(task); | |
1400 | if (mm && mm != current->mm && | |
1401 | !ptrace_may_access(task, mode)) { | |
1402 | mmput(mm); | |
1403 | mm = ERR_PTR(-EACCES); | |
1404 | } | |
f7cfd871 | 1405 | up_read(&task->signal->exec_update_lock); |
8cdb878d CY |
1406 | |
1407 | return mm; | |
1408 | } | |
1409 | ||
57b59c4a | 1410 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1411 | { |
d68b46fe | 1412 | struct completion *vfork; |
c415c3b4 | 1413 | |
d68b46fe ON |
1414 | task_lock(tsk); |
1415 | vfork = tsk->vfork_done; | |
1416 | if (likely(vfork)) { | |
1417 | tsk->vfork_done = NULL; | |
1418 | complete(vfork); | |
1419 | } | |
1420 | task_unlock(tsk); | |
1421 | } | |
1422 | ||
1423 | static int wait_for_vfork_done(struct task_struct *child, | |
1424 | struct completion *vfork) | |
1425 | { | |
1426 | int killed; | |
1427 | ||
1428 | freezer_do_not_count(); | |
76f969e8 | 1429 | cgroup_enter_frozen(); |
d68b46fe | 1430 | killed = wait_for_completion_killable(vfork); |
76f969e8 | 1431 | cgroup_leave_frozen(false); |
d68b46fe ON |
1432 | freezer_count(); |
1433 | ||
1434 | if (killed) { | |
1435 | task_lock(child); | |
1436 | child->vfork_done = NULL; | |
1437 | task_unlock(child); | |
1438 | } | |
1439 | ||
1440 | put_task_struct(child); | |
1441 | return killed; | |
c415c3b4 ON |
1442 | } |
1443 | ||
1da177e4 LT |
1444 | /* Please note the differences between mmput and mm_release. |
1445 | * mmput is called whenever we stop holding onto a mm_struct, | |
1446 | * error success whatever. | |
1447 | * | |
1448 | * mm_release is called after a mm_struct has been removed | |
1449 | * from the current process. | |
1450 | * | |
1451 | * This difference is important for error handling, when we | |
1452 | * only half set up a mm_struct for a new process and need to restore | |
1453 | * the old one. Because we mmput the new mm_struct before | |
1454 | * restoring the old one. . . | |
1455 | * Eric Biederman 10 January 1998 | |
1456 | */ | |
4610ba7a | 1457 | static void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1da177e4 | 1458 | { |
0326f5a9 SD |
1459 | uprobe_free_utask(tsk); |
1460 | ||
1da177e4 LT |
1461 | /* Get rid of any cached register state */ |
1462 | deactivate_mm(tsk, mm); | |
1463 | ||
fec1d011 | 1464 | /* |
735f2770 MH |
1465 | * Signal userspace if we're not exiting with a core dump |
1466 | * because we want to leave the value intact for debugging | |
1467 | * purposes. | |
fec1d011 | 1468 | */ |
9c8a8228 | 1469 | if (tsk->clear_child_tid) { |
92307383 | 1470 | if (atomic_read(&mm->mm_users) > 1) { |
9c8a8228 ED |
1471 | /* |
1472 | * We don't check the error code - if userspace has | |
1473 | * not set up a proper pointer then tough luck. | |
1474 | */ | |
1475 | put_user(0, tsk->clear_child_tid); | |
2de0db99 DB |
1476 | do_futex(tsk->clear_child_tid, FUTEX_WAKE, |
1477 | 1, NULL, NULL, 0, 0); | |
9c8a8228 | 1478 | } |
1da177e4 | 1479 | tsk->clear_child_tid = NULL; |
1da177e4 | 1480 | } |
f7505d64 KK |
1481 | |
1482 | /* | |
1483 | * All done, finally we can wake up parent and return this mm to him. | |
1484 | * Also kthread_stop() uses this completion for synchronization. | |
1485 | */ | |
1486 | if (tsk->vfork_done) | |
1487 | complete_vfork_done(tsk); | |
1da177e4 LT |
1488 | } |
1489 | ||
4610ba7a TG |
1490 | void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm) |
1491 | { | |
150d7158 | 1492 | futex_exit_release(tsk); |
4610ba7a TG |
1493 | mm_release(tsk, mm); |
1494 | } | |
1495 | ||
1496 | void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1497 | { | |
150d7158 | 1498 | futex_exec_release(tsk); |
4610ba7a TG |
1499 | mm_release(tsk, mm); |
1500 | } | |
1501 | ||
13585fa0 NA |
1502 | /** |
1503 | * dup_mm() - duplicates an existing mm structure | |
1504 | * @tsk: the task_struct with which the new mm will be associated. | |
1505 | * @oldmm: the mm to duplicate. | |
1506 | * | |
1507 | * Allocates a new mm structure and duplicates the provided @oldmm structure | |
1508 | * content into it. | |
1509 | * | |
1510 | * Return: the duplicated mm or NULL on failure. | |
a0a7ec30 | 1511 | */ |
13585fa0 NA |
1512 | static struct mm_struct *dup_mm(struct task_struct *tsk, |
1513 | struct mm_struct *oldmm) | |
a0a7ec30 | 1514 | { |
13585fa0 | 1515 | struct mm_struct *mm; |
a0a7ec30 JD |
1516 | int err; |
1517 | ||
a0a7ec30 JD |
1518 | mm = allocate_mm(); |
1519 | if (!mm) | |
1520 | goto fail_nomem; | |
1521 | ||
1522 | memcpy(mm, oldmm, sizeof(*mm)); | |
1523 | ||
bfedb589 | 1524 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1525 | goto fail_nomem; |
1526 | ||
a0a7ec30 JD |
1527 | err = dup_mmap(mm, oldmm); |
1528 | if (err) | |
1529 | goto free_pt; | |
1530 | ||
1531 | mm->hiwater_rss = get_mm_rss(mm); | |
1532 | mm->hiwater_vm = mm->total_vm; | |
1533 | ||
801460d0 HS |
1534 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1535 | goto free_pt; | |
1536 | ||
a0a7ec30 JD |
1537 | return mm; |
1538 | ||
1539 | free_pt: | |
801460d0 HS |
1540 | /* don't put binfmt in mmput, we haven't got module yet */ |
1541 | mm->binfmt = NULL; | |
c3f3ce04 | 1542 | mm_init_owner(mm, NULL); |
a0a7ec30 JD |
1543 | mmput(mm); |
1544 | ||
1545 | fail_nomem: | |
1546 | return NULL; | |
a0a7ec30 JD |
1547 | } |
1548 | ||
fb0a685c | 1549 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1550 | { |
fb0a685c | 1551 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1552 | |
1553 | tsk->min_flt = tsk->maj_flt = 0; | |
1554 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1555 | #ifdef CONFIG_DETECT_HUNG_TASK |
1556 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
a2e51445 | 1557 | tsk->last_switch_time = 0; |
17406b82 | 1558 | #endif |
1da177e4 LT |
1559 | |
1560 | tsk->mm = NULL; | |
1561 | tsk->active_mm = NULL; | |
1562 | ||
1563 | /* | |
1564 | * Are we cloning a kernel thread? | |
1565 | * | |
1566 | * We need to steal a active VM for that.. | |
1567 | */ | |
1568 | oldmm = current->mm; | |
1569 | if (!oldmm) | |
1570 | return 0; | |
1571 | ||
1572 | if (clone_flags & CLONE_VM) { | |
3fce371b | 1573 | mmget(oldmm); |
1da177e4 | 1574 | mm = oldmm; |
a6895399 REB |
1575 | } else { |
1576 | mm = dup_mm(tsk, current->mm); | |
1577 | if (!mm) | |
1578 | return -ENOMEM; | |
1da177e4 LT |
1579 | } |
1580 | ||
1da177e4 LT |
1581 | tsk->mm = mm; |
1582 | tsk->active_mm = mm; | |
1583 | return 0; | |
1da177e4 LT |
1584 | } |
1585 | ||
a39bc516 | 1586 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1587 | { |
498052bb | 1588 | struct fs_struct *fs = current->fs; |
1da177e4 | 1589 | if (clone_flags & CLONE_FS) { |
498052bb | 1590 | /* tsk->fs is already what we want */ |
2a4419b5 | 1591 | spin_lock(&fs->lock); |
498052bb | 1592 | if (fs->in_exec) { |
2a4419b5 | 1593 | spin_unlock(&fs->lock); |
498052bb AV |
1594 | return -EAGAIN; |
1595 | } | |
1596 | fs->users++; | |
2a4419b5 | 1597 | spin_unlock(&fs->lock); |
1da177e4 LT |
1598 | return 0; |
1599 | } | |
498052bb | 1600 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1601 | if (!tsk->fs) |
1602 | return -ENOMEM; | |
1603 | return 0; | |
1604 | } | |
1605 | ||
fb0a685c | 1606 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1607 | { |
1608 | struct files_struct *oldf, *newf; | |
1609 | int error = 0; | |
1610 | ||
1611 | /* | |
1612 | * A background process may not have any files ... | |
1613 | */ | |
1614 | oldf = current->files; | |
1615 | if (!oldf) | |
1616 | goto out; | |
1617 | ||
1618 | if (clone_flags & CLONE_FILES) { | |
1619 | atomic_inc(&oldf->count); | |
1620 | goto out; | |
1621 | } | |
1622 | ||
60997c3d | 1623 | newf = dup_fd(oldf, NR_OPEN_MAX, &error); |
a016f338 JD |
1624 | if (!newf) |
1625 | goto out; | |
1626 | ||
1627 | tsk->files = newf; | |
1628 | error = 0; | |
1629 | out: | |
1630 | return error; | |
1631 | } | |
1632 | ||
a39bc516 | 1633 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1634 | { |
1635 | struct sighand_struct *sig; | |
1636 | ||
60348802 | 1637 | if (clone_flags & CLONE_SIGHAND) { |
d036bda7 | 1638 | refcount_inc(¤t->sighand->count); |
1da177e4 LT |
1639 | return 0; |
1640 | } | |
1641 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
0c282b06 | 1642 | RCU_INIT_POINTER(tsk->sighand, sig); |
1da177e4 LT |
1643 | if (!sig) |
1644 | return -ENOMEM; | |
9d7fb042 | 1645 | |
d036bda7 | 1646 | refcount_set(&sig->count, 1); |
06e62a46 | 1647 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1648 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
06e62a46 | 1649 | spin_unlock_irq(¤t->sighand->siglock); |
b612e5df CB |
1650 | |
1651 | /* Reset all signal handler not set to SIG_IGN to SIG_DFL. */ | |
1652 | if (clone_flags & CLONE_CLEAR_SIGHAND) | |
1653 | flush_signal_handlers(tsk, 0); | |
1654 | ||
1da177e4 LT |
1655 | return 0; |
1656 | } | |
1657 | ||
a7e5328a | 1658 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1659 | { |
d036bda7 | 1660 | if (refcount_dec_and_test(&sighand->count)) { |
d80e731e | 1661 | signalfd_cleanup(sighand); |
392809b2 | 1662 | /* |
5f0d5a3a | 1663 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it |
392809b2 ON |
1664 | * without an RCU grace period, see __lock_task_sighand(). |
1665 | */ | |
c81addc9 | 1666 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1667 | } |
c81addc9 ON |
1668 | } |
1669 | ||
f06febc9 FM |
1670 | /* |
1671 | * Initialize POSIX timer handling for a thread group. | |
1672 | */ | |
1673 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1674 | { | |
2b69942f | 1675 | struct posix_cputimers *pct = &sig->posix_cputimers; |
78d7d407 JS |
1676 | unsigned long cpu_limit; |
1677 | ||
316c1608 | 1678 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
3a245c0f | 1679 | posix_cputimers_group_init(pct, cpu_limit); |
f06febc9 FM |
1680 | } |
1681 | ||
a39bc516 | 1682 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1683 | { |
1684 | struct signal_struct *sig; | |
1da177e4 | 1685 | |
4ab6c083 | 1686 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1687 | return 0; |
490dea45 | 1688 | |
a56704ef | 1689 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1690 | tsk->signal = sig; |
1691 | if (!sig) | |
1692 | return -ENOMEM; | |
1693 | ||
b3ac022c | 1694 | sig->nr_threads = 1; |
1da177e4 | 1695 | atomic_set(&sig->live, 1); |
60d4de3f | 1696 | refcount_set(&sig->sigcnt, 1); |
0c740d0a ON |
1697 | |
1698 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1699 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1700 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1701 | ||
1da177e4 | 1702 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1703 | sig->curr_target = tsk; |
1da177e4 | 1704 | init_sigpending(&sig->shared_pending); |
c3ad2c3b | 1705 | INIT_HLIST_HEAD(&sig->multiprocess); |
e78c3496 | 1706 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1707 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1708 | |
baa73d9e | 1709 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1710 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1711 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1712 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1713 | #endif |
1da177e4 | 1714 | |
1da177e4 LT |
1715 | task_lock(current->group_leader); |
1716 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1717 | task_unlock(current->group_leader); | |
1718 | ||
6279a751 ON |
1719 | posix_cpu_timers_init_group(sig); |
1720 | ||
522ed776 | 1721 | tty_audit_fork(sig); |
5091faa4 | 1722 | sched_autogroup_fork(sig); |
522ed776 | 1723 | |
a63d83f4 | 1724 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1725 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1726 | |
9b1bf12d | 1727 | mutex_init(&sig->cred_guard_mutex); |
f7cfd871 | 1728 | init_rwsem(&sig->exec_update_lock); |
9b1bf12d | 1729 | |
1da177e4 LT |
1730 | return 0; |
1731 | } | |
1732 | ||
dbd95212 KC |
1733 | static void copy_seccomp(struct task_struct *p) |
1734 | { | |
1735 | #ifdef CONFIG_SECCOMP | |
1736 | /* | |
1737 | * Must be called with sighand->lock held, which is common to | |
1738 | * all threads in the group. Holding cred_guard_mutex is not | |
1739 | * needed because this new task is not yet running and cannot | |
1740 | * be racing exec. | |
1741 | */ | |
69f6a34b | 1742 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1743 | |
1744 | /* Ref-count the new filter user, and assign it. */ | |
1745 | get_seccomp_filter(current); | |
1746 | p->seccomp = current->seccomp; | |
1747 | ||
1748 | /* | |
1749 | * Explicitly enable no_new_privs here in case it got set | |
1750 | * between the task_struct being duplicated and holding the | |
1751 | * sighand lock. The seccomp state and nnp must be in sync. | |
1752 | */ | |
1753 | if (task_no_new_privs(current)) | |
1754 | task_set_no_new_privs(p); | |
1755 | ||
1756 | /* | |
1757 | * If the parent gained a seccomp mode after copying thread | |
1758 | * flags and between before we held the sighand lock, we have | |
1759 | * to manually enable the seccomp thread flag here. | |
1760 | */ | |
1761 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
23d67a54 | 1762 | set_task_syscall_work(p, SECCOMP); |
dbd95212 KC |
1763 | #endif |
1764 | } | |
1765 | ||
17da2bd9 | 1766 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1767 | { |
1768 | current->clear_child_tid = tidptr; | |
1769 | ||
b488893a | 1770 | return task_pid_vnr(current); |
1da177e4 LT |
1771 | } |
1772 | ||
a39bc516 | 1773 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1774 | { |
1d615482 | 1775 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1776 | #ifdef CONFIG_RT_MUTEXES |
a23ba907 | 1777 | p->pi_waiters = RB_ROOT_CACHED; |
e96a7705 | 1778 | p->pi_top_task = NULL; |
23f78d4a | 1779 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1780 | #endif |
1781 | } | |
1782 | ||
2c470475 EB |
1783 | static inline void init_task_pid_links(struct task_struct *task) |
1784 | { | |
1785 | enum pid_type type; | |
1786 | ||
96e1e984 | 1787 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) |
2c470475 | 1788 | INIT_HLIST_NODE(&task->pid_links[type]); |
2c470475 EB |
1789 | } |
1790 | ||
81907739 ON |
1791 | static inline void |
1792 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1793 | { | |
2c470475 EB |
1794 | if (type == PIDTYPE_PID) |
1795 | task->thread_pid = pid; | |
1796 | else | |
1797 | task->signal->pids[type] = pid; | |
81907739 ON |
1798 | } |
1799 | ||
6bfbaa51 IM |
1800 | static inline void rcu_copy_process(struct task_struct *p) |
1801 | { | |
1802 | #ifdef CONFIG_PREEMPT_RCU | |
1803 | p->rcu_read_lock_nesting = 0; | |
1804 | p->rcu_read_unlock_special.s = 0; | |
1805 | p->rcu_blocked_node = NULL; | |
1806 | INIT_LIST_HEAD(&p->rcu_node_entry); | |
1807 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1808 | #ifdef CONFIG_TASKS_RCU | |
1809 | p->rcu_tasks_holdout = false; | |
1810 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); | |
1811 | p->rcu_tasks_idle_cpu = -1; | |
1812 | #endif /* #ifdef CONFIG_TASKS_RCU */ | |
d5f177d3 PM |
1813 | #ifdef CONFIG_TASKS_TRACE_RCU |
1814 | p->trc_reader_nesting = 0; | |
276c4104 | 1815 | p->trc_reader_special.s = 0; |
d5f177d3 | 1816 | INIT_LIST_HEAD(&p->trc_holdout_list); |
434c9eef | 1817 | INIT_LIST_HEAD(&p->trc_blkd_node); |
d5f177d3 | 1818 | #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ |
6bfbaa51 IM |
1819 | } |
1820 | ||
3695eae5 CB |
1821 | struct pid *pidfd_pid(const struct file *file) |
1822 | { | |
1823 | if (file->f_op == &pidfd_fops) | |
1824 | return file->private_data; | |
1825 | ||
1826 | return ERR_PTR(-EBADF); | |
1827 | } | |
1828 | ||
b3e58382 CB |
1829 | static int pidfd_release(struct inode *inode, struct file *file) |
1830 | { | |
1831 | struct pid *pid = file->private_data; | |
1832 | ||
1833 | file->private_data = NULL; | |
1834 | put_pid(pid); | |
1835 | return 0; | |
1836 | } | |
1837 | ||
1838 | #ifdef CONFIG_PROC_FS | |
15d42eb2 CK |
1839 | /** |
1840 | * pidfd_show_fdinfo - print information about a pidfd | |
1841 | * @m: proc fdinfo file | |
1842 | * @f: file referencing a pidfd | |
1843 | * | |
1844 | * Pid: | |
1845 | * This function will print the pid that a given pidfd refers to in the | |
1846 | * pid namespace of the procfs instance. | |
1847 | * If the pid namespace of the process is not a descendant of the pid | |
1848 | * namespace of the procfs instance 0 will be shown as its pid. This is | |
1849 | * similar to calling getppid() on a process whose parent is outside of | |
1850 | * its pid namespace. | |
1851 | * | |
1852 | * NSpid: | |
1853 | * If pid namespaces are supported then this function will also print | |
1854 | * the pid of a given pidfd refers to for all descendant pid namespaces | |
1855 | * starting from the current pid namespace of the instance, i.e. the | |
1856 | * Pid field and the first entry in the NSpid field will be identical. | |
1857 | * If the pid namespace of the process is not a descendant of the pid | |
1858 | * namespace of the procfs instance 0 will be shown as its first NSpid | |
1859 | * entry and no others will be shown. | |
1860 | * Note that this differs from the Pid and NSpid fields in | |
1861 | * /proc/<pid>/status where Pid and NSpid are always shown relative to | |
1862 | * the pid namespace of the procfs instance. The difference becomes | |
1863 | * obvious when sending around a pidfd between pid namespaces from a | |
a8ca6b13 | 1864 | * different branch of the tree, i.e. where no ancestral relation is |
15d42eb2 CK |
1865 | * present between the pid namespaces: |
1866 | * - create two new pid namespaces ns1 and ns2 in the initial pid | |
1867 | * namespace (also take care to create new mount namespaces in the | |
1868 | * new pid namespace and mount procfs) | |
1869 | * - create a process with a pidfd in ns1 | |
1870 | * - send pidfd from ns1 to ns2 | |
1871 | * - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid | |
1872 | * have exactly one entry, which is 0 | |
1873 | */ | |
b3e58382 CB |
1874 | static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) |
1875 | { | |
b3e58382 | 1876 | struct pid *pid = f->private_data; |
3d6d8da4 CB |
1877 | struct pid_namespace *ns; |
1878 | pid_t nr = -1; | |
15d42eb2 | 1879 | |
3d6d8da4 | 1880 | if (likely(pid_has_task(pid, PIDTYPE_PID))) { |
9d78edea | 1881 | ns = proc_pid_ns(file_inode(m->file)->i_sb); |
3d6d8da4 CB |
1882 | nr = pid_nr_ns(pid, ns); |
1883 | } | |
1884 | ||
1885 | seq_put_decimal_ll(m, "Pid:\t", nr); | |
b3e58382 | 1886 | |
15d42eb2 | 1887 | #ifdef CONFIG_PID_NS |
3d6d8da4 CB |
1888 | seq_put_decimal_ll(m, "\nNSpid:\t", nr); |
1889 | if (nr > 0) { | |
15d42eb2 | 1890 | int i; |
b3e58382 | 1891 | |
15d42eb2 CK |
1892 | /* If nr is non-zero it means that 'pid' is valid and that |
1893 | * ns, i.e. the pid namespace associated with the procfs | |
1894 | * instance, is in the pid namespace hierarchy of pid. | |
1895 | * Start at one below the already printed level. | |
1896 | */ | |
1897 | for (i = ns->level + 1; i <= pid->level; i++) | |
3d6d8da4 | 1898 | seq_put_decimal_ll(m, "\t", pid->numbers[i].nr); |
15d42eb2 CK |
1899 | } |
1900 | #endif | |
b3e58382 CB |
1901 | seq_putc(m, '\n'); |
1902 | } | |
1903 | #endif | |
1904 | ||
b53b0b9d JFG |
1905 | /* |
1906 | * Poll support for process exit notification. | |
1907 | */ | |
9e77716a | 1908 | static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) |
b53b0b9d | 1909 | { |
b53b0b9d | 1910 | struct pid *pid = file->private_data; |
9e77716a | 1911 | __poll_t poll_flags = 0; |
b53b0b9d JFG |
1912 | |
1913 | poll_wait(file, &pid->wait_pidfd, pts); | |
1914 | ||
b53b0b9d JFG |
1915 | /* |
1916 | * Inform pollers only when the whole thread group exits. | |
1917 | * If the thread group leader exits before all other threads in the | |
1918 | * group, then poll(2) should block, similar to the wait(2) family. | |
1919 | */ | |
38fd525a | 1920 | if (thread_group_exited(pid)) |
9e77716a | 1921 | poll_flags = EPOLLIN | EPOLLRDNORM; |
b53b0b9d JFG |
1922 | |
1923 | return poll_flags; | |
1924 | } | |
1925 | ||
b3e58382 CB |
1926 | const struct file_operations pidfd_fops = { |
1927 | .release = pidfd_release, | |
b53b0b9d | 1928 | .poll = pidfd_poll, |
b3e58382 CB |
1929 | #ifdef CONFIG_PROC_FS |
1930 | .show_fdinfo = pidfd_show_fdinfo, | |
1931 | #endif | |
1932 | }; | |
1933 | ||
c3f3ce04 AA |
1934 | static void __delayed_free_task(struct rcu_head *rhp) |
1935 | { | |
1936 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); | |
1937 | ||
1938 | free_task(tsk); | |
1939 | } | |
1940 | ||
1941 | static __always_inline void delayed_free_task(struct task_struct *tsk) | |
1942 | { | |
1943 | if (IS_ENABLED(CONFIG_MEMCG)) | |
1944 | call_rcu(&tsk->rcu, __delayed_free_task); | |
1945 | else | |
1946 | free_task(tsk); | |
1947 | } | |
1948 | ||
67197a4f SB |
1949 | static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk) |
1950 | { | |
1951 | /* Skip if kernel thread */ | |
1952 | if (!tsk->mm) | |
1953 | return; | |
1954 | ||
1955 | /* Skip if spawning a thread or using vfork */ | |
1956 | if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM) | |
1957 | return; | |
1958 | ||
1959 | /* We need to synchronize with __set_oom_adj */ | |
1960 | mutex_lock(&oom_adj_mutex); | |
1961 | set_bit(MMF_MULTIPROCESS, &tsk->mm->flags); | |
1962 | /* Update the values in case they were changed after copy_signal */ | |
1963 | tsk->signal->oom_score_adj = current->signal->oom_score_adj; | |
1964 | tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min; | |
1965 | mutex_unlock(&oom_adj_mutex); | |
1966 | } | |
1967 | ||
79257534 DBO |
1968 | #ifdef CONFIG_RV |
1969 | static void rv_task_fork(struct task_struct *p) | |
1970 | { | |
1971 | int i; | |
1972 | ||
1973 | for (i = 0; i < RV_PER_TASK_MONITORS; i++) | |
1974 | p->rv[i].da_mon.monitoring = false; | |
1975 | } | |
1976 | #else | |
1977 | #define rv_task_fork(p) do {} while (0) | |
1978 | #endif | |
1979 | ||
1da177e4 LT |
1980 | /* |
1981 | * This creates a new process as a copy of the old one, | |
1982 | * but does not actually start it yet. | |
1983 | * | |
1984 | * It copies the registers, and all the appropriate | |
1985 | * parts of the process environment (as per the clone | |
1986 | * flags). The actual kick-off is left to the caller. | |
1987 | */ | |
0766f788 | 1988 | static __latent_entropy struct task_struct *copy_process( |
09a05394 | 1989 | struct pid *pid, |
3033f14a | 1990 | int trace, |
7f192e3c CB |
1991 | int node, |
1992 | struct kernel_clone_args *args) | |
1da177e4 | 1993 | { |
b3e58382 | 1994 | int pidfd = -1, retval; |
a24efe62 | 1995 | struct task_struct *p; |
c3ad2c3b | 1996 | struct multiprocess_signals delayed; |
6fd2fe49 | 1997 | struct file *pidfile = NULL; |
c5febea0 | 1998 | const u64 clone_flags = args->flags; |
769071ac | 1999 | struct nsproxy *nsp = current->nsproxy; |
1da177e4 | 2000 | |
667b6094 MPS |
2001 | /* |
2002 | * Don't allow sharing the root directory with processes in a different | |
2003 | * namespace | |
2004 | */ | |
1da177e4 LT |
2005 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
2006 | return ERR_PTR(-EINVAL); | |
2007 | ||
e66eded8 EB |
2008 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
2009 | return ERR_PTR(-EINVAL); | |
2010 | ||
1da177e4 LT |
2011 | /* |
2012 | * Thread groups must share signals as well, and detached threads | |
2013 | * can only be started up within the thread group. | |
2014 | */ | |
2015 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
2016 | return ERR_PTR(-EINVAL); | |
2017 | ||
2018 | /* | |
2019 | * Shared signal handlers imply shared VM. By way of the above, | |
2020 | * thread groups also imply shared VM. Blocking this case allows | |
2021 | * for various simplifications in other code. | |
2022 | */ | |
2023 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
2024 | return ERR_PTR(-EINVAL); | |
2025 | ||
123be07b SB |
2026 | /* |
2027 | * Siblings of global init remain as zombies on exit since they are | |
2028 | * not reaped by their parent (swapper). To solve this and to avoid | |
2029 | * multi-rooted process trees, prevent global and container-inits | |
2030 | * from creating siblings. | |
2031 | */ | |
2032 | if ((clone_flags & CLONE_PARENT) && | |
2033 | current->signal->flags & SIGNAL_UNKILLABLE) | |
2034 | return ERR_PTR(-EINVAL); | |
2035 | ||
8382fcac | 2036 | /* |
40a0d32d | 2037 | * If the new process will be in a different pid or user namespace |
faf00da5 | 2038 | * do not allow it to share a thread group with the forking task. |
8382fcac | 2039 | */ |
faf00da5 | 2040 | if (clone_flags & CLONE_THREAD) { |
40a0d32d | 2041 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
769071ac AV |
2042 | (task_active_pid_ns(current) != nsp->pid_ns_for_children)) |
2043 | return ERR_PTR(-EINVAL); | |
2044 | } | |
2045 | ||
2046 | /* | |
2047 | * If the new process will be in a different time namespace | |
2048 | * do not allow it to share VM or a thread group with the forking task. | |
133e2d3e AV |
2049 | * |
2050 | * On vfork, the child process enters the target time namespace only | |
2051 | * after exec. | |
769071ac | 2052 | */ |
133e2d3e | 2053 | if ((clone_flags & (CLONE_VM | CLONE_VFORK)) == CLONE_VM) { |
769071ac | 2054 | if (nsp->time_ns != nsp->time_ns_for_children) |
40a0d32d ON |
2055 | return ERR_PTR(-EINVAL); |
2056 | } | |
8382fcac | 2057 | |
b3e58382 | 2058 | if (clone_flags & CLONE_PIDFD) { |
b3e58382 | 2059 | /* |
b3e58382 CB |
2060 | * - CLONE_DETACHED is blocked so that we can potentially |
2061 | * reuse it later for CLONE_PIDFD. | |
2062 | * - CLONE_THREAD is blocked until someone really needs it. | |
2063 | */ | |
7f192e3c | 2064 | if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) |
b3e58382 | 2065 | return ERR_PTR(-EINVAL); |
b3e58382 CB |
2066 | } |
2067 | ||
c3ad2c3b EB |
2068 | /* |
2069 | * Force any signals received before this point to be delivered | |
2070 | * before the fork happens. Collect up signals sent to multiple | |
2071 | * processes that happen during the fork and delay them so that | |
2072 | * they appear to happen after the fork. | |
2073 | */ | |
2074 | sigemptyset(&delayed.signal); | |
2075 | INIT_HLIST_NODE(&delayed.node); | |
2076 | ||
2077 | spin_lock_irq(¤t->sighand->siglock); | |
2078 | if (!(clone_flags & CLONE_THREAD)) | |
2079 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess); | |
2080 | recalc_sigpending(); | |
2081 | spin_unlock_irq(¤t->sighand->siglock); | |
2082 | retval = -ERESTARTNOINTR; | |
66ae0d1e | 2083 | if (task_sigpending(current)) |
c3ad2c3b EB |
2084 | goto fork_out; |
2085 | ||
1da177e4 | 2086 | retval = -ENOMEM; |
725fc629 | 2087 | p = dup_task_struct(current, node); |
1da177e4 LT |
2088 | if (!p) |
2089 | goto fork_out; | |
753550eb EB |
2090 | p->flags &= ~PF_KTHREAD; |
2091 | if (args->kthread) | |
2092 | p->flags |= PF_KTHREAD; | |
b16b3855 JA |
2093 | if (args->io_thread) { |
2094 | /* | |
2095 | * Mark us an IO worker, and block any signal that isn't | |
2096 | * fatal or STOP | |
2097 | */ | |
cc440e87 | 2098 | p->flags |= PF_IO_WORKER; |
b16b3855 JA |
2099 | siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
2100 | } | |
1da177e4 | 2101 | |
7f192e3c | 2102 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL; |
4d6501dc VN |
2103 | /* |
2104 | * Clear TID on mm_release()? | |
2105 | */ | |
7f192e3c | 2106 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL; |
4d6501dc | 2107 | |
f7e8b616 SR |
2108 | ftrace_graph_init_task(p); |
2109 | ||
bea493a0 PZ |
2110 | rt_mutex_init_task(p); |
2111 | ||
a21ee605 | 2112 | lockdep_assert_irqs_enabled(); |
d12c1a37 | 2113 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
2114 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
2115 | #endif | |
8f2f9c4d EB |
2116 | retval = copy_creds(p, clone_flags); |
2117 | if (retval < 0) | |
2118 | goto bad_fork_free; | |
2119 | ||
1da177e4 | 2120 | retval = -EAGAIN; |
21d1c5e3 | 2121 | if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { |
b57922b6 EP |
2122 | if (p->real_cred->user != INIT_USER && |
2123 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
8f2f9c4d | 2124 | goto bad_fork_cleanup_count; |
1da177e4 | 2125 | } |
72fa5997 | 2126 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 2127 | |
1da177e4 LT |
2128 | /* |
2129 | * If multiple threads are within copy_process(), then this check | |
2130 | * triggers too late. This doesn't hurt, the check is only there | |
2131 | * to stop root fork bombs. | |
2132 | */ | |
04ec93fe | 2133 | retval = -EAGAIN; |
c17d1a3a | 2134 | if (data_race(nr_threads >= max_threads)) |
1da177e4 LT |
2135 | goto bad_fork_cleanup_count; |
2136 | ||
ca74e92b | 2137 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
a8ea6fc9 | 2138 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY); |
514ddb44 | 2139 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
2140 | INIT_LIST_HEAD(&p->children); |
2141 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 2142 | rcu_copy_process(p); |
1da177e4 LT |
2143 | p->vfork_done = NULL; |
2144 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 2145 | |
1da177e4 LT |
2146 | init_sigpending(&p->pending); |
2147 | ||
64861634 | 2148 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 2149 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 2150 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 2151 | #endif |
9d7fb042 PZ |
2152 | prev_cputime_init(&p->prev_cputime); |
2153 | ||
6a61671b | 2154 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
bac5b6b6 FW |
2155 | seqcount_init(&p->vtime.seqcount); |
2156 | p->vtime.starttime = 0; | |
2157 | p->vtime.state = VTIME_INACTIVE; | |
6a61671b FW |
2158 | #endif |
2159 | ||
0f212204 JA |
2160 | #ifdef CONFIG_IO_URING |
2161 | p->io_uring = NULL; | |
2162 | #endif | |
2163 | ||
a3a2e76c KH |
2164 | #if defined(SPLIT_RSS_COUNTING) |
2165 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
2166 | #endif | |
172ba844 | 2167 | |
6976675d AV |
2168 | p->default_timer_slack_ns = current->timer_slack_ns; |
2169 | ||
eb414681 JW |
2170 | #ifdef CONFIG_PSI |
2171 | p->psi_flags = 0; | |
2172 | #endif | |
2173 | ||
5995477a | 2174 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
2175 | acct_clear_integrals(p); |
2176 | ||
3a245c0f | 2177 | posix_cputimers_init(&p->posix_cputimers); |
1da177e4 | 2178 | |
1da177e4 | 2179 | p->io_context = NULL; |
c0b0ae8a | 2180 | audit_set_context(p, NULL); |
b4f48b63 | 2181 | cgroup_fork(p); |
343f4c49 | 2182 | if (args->kthread) { |
40966e31 | 2183 | if (!set_kthread_struct(p)) |
ff8288ff | 2184 | goto bad_fork_cleanup_delayacct; |
40966e31 | 2185 | } |
1da177e4 | 2186 | #ifdef CONFIG_NUMA |
846a16bf | 2187 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
2188 | if (IS_ERR(p->mempolicy)) { |
2189 | retval = PTR_ERR(p->mempolicy); | |
2190 | p->mempolicy = NULL; | |
ff8288ff | 2191 | goto bad_fork_cleanup_delayacct; |
fb0a685c | 2192 | } |
1da177e4 | 2193 | #endif |
778d3b0f MH |
2194 | #ifdef CONFIG_CPUSETS |
2195 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
2196 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
b7505861 | 2197 | seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock); |
778d3b0f | 2198 | #endif |
de30a2b3 | 2199 | #ifdef CONFIG_TRACE_IRQFLAGS |
0584df9c ME |
2200 | memset(&p->irqtrace, 0, sizeof(p->irqtrace)); |
2201 | p->irqtrace.hardirq_disable_ip = _THIS_IP_; | |
2202 | p->irqtrace.softirq_enable_ip = _THIS_IP_; | |
2203 | p->softirqs_enabled = 1; | |
2204 | p->softirq_context = 0; | |
de30a2b3 | 2205 | #endif |
8bcbde54 DH |
2206 | |
2207 | p->pagefault_disabled = 0; | |
2208 | ||
fbb9ce95 | 2209 | #ifdef CONFIG_LOCKDEP |
b09be676 | 2210 | lockdep_init_task(p); |
fbb9ce95 | 2211 | #endif |
1da177e4 | 2212 | |
408894ee IM |
2213 | #ifdef CONFIG_DEBUG_MUTEXES |
2214 | p->blocked_on = NULL; /* not blocked yet */ | |
2215 | #endif | |
cafe5635 KO |
2216 | #ifdef CONFIG_BCACHE |
2217 | p->sequential_io = 0; | |
2218 | p->sequential_io_avg = 0; | |
2219 | #endif | |
a10787e6 SL |
2220 | #ifdef CONFIG_BPF_SYSCALL |
2221 | RCU_INIT_POINTER(p->bpf_storage, NULL); | |
c7603cfa | 2222 | p->bpf_ctx = NULL; |
a10787e6 | 2223 | #endif |
0f481406 | 2224 | |
3c90e6e9 | 2225 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
2226 | retval = sched_fork(clone_flags, p); |
2227 | if (retval) | |
2228 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 2229 | |
2b26f0aa | 2230 | retval = perf_event_init_task(p, clone_flags); |
6ab423e0 PZ |
2231 | if (retval) |
2232 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
2233 | retval = audit_alloc(p); |
2234 | if (retval) | |
6c72e350 | 2235 | goto bad_fork_cleanup_perf; |
1da177e4 | 2236 | /* copy all the process information */ |
ab602f79 | 2237 | shm_init_task(p); |
e4e55b47 | 2238 | retval = security_task_alloc(p, clone_flags); |
fb0a685c | 2239 | if (retval) |
1da177e4 | 2240 | goto bad_fork_cleanup_audit; |
e4e55b47 TH |
2241 | retval = copy_semundo(clone_flags, p); |
2242 | if (retval) | |
2243 | goto bad_fork_cleanup_security; | |
fb0a685c DRO |
2244 | retval = copy_files(clone_flags, p); |
2245 | if (retval) | |
1da177e4 | 2246 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
2247 | retval = copy_fs(clone_flags, p); |
2248 | if (retval) | |
1da177e4 | 2249 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
2250 | retval = copy_sighand(clone_flags, p); |
2251 | if (retval) | |
1da177e4 | 2252 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
2253 | retval = copy_signal(clone_flags, p); |
2254 | if (retval) | |
1da177e4 | 2255 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
2256 | retval = copy_mm(clone_flags, p); |
2257 | if (retval) | |
1da177e4 | 2258 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
2259 | retval = copy_namespaces(clone_flags, p); |
2260 | if (retval) | |
d84f4f99 | 2261 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
2262 | retval = copy_io(clone_flags, p); |
2263 | if (retval) | |
fd0928df | 2264 | goto bad_fork_cleanup_namespaces; |
c5febea0 | 2265 | retval = copy_thread(p, args); |
1da177e4 | 2266 | if (retval) |
fd0928df | 2267 | goto bad_fork_cleanup_io; |
1da177e4 | 2268 | |
afaef01c AP |
2269 | stackleak_task_init(p); |
2270 | ||
425fb2b4 | 2271 | if (pid != &init_struct_pid) { |
49cb2fc4 AR |
2272 | pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid, |
2273 | args->set_tid_size); | |
35f71bc0 MH |
2274 | if (IS_ERR(pid)) { |
2275 | retval = PTR_ERR(pid); | |
0740aa5f | 2276 | goto bad_fork_cleanup_thread; |
35f71bc0 | 2277 | } |
425fb2b4 PE |
2278 | } |
2279 | ||
b3e58382 CB |
2280 | /* |
2281 | * This has to happen after we've potentially unshared the file | |
2282 | * descriptor table (so that the pidfd doesn't leak into the child | |
2283 | * if the fd table isn't shared). | |
2284 | */ | |
2285 | if (clone_flags & CLONE_PIDFD) { | |
6fd2fe49 | 2286 | retval = get_unused_fd_flags(O_RDWR | O_CLOEXEC); |
b3e58382 CB |
2287 | if (retval < 0) |
2288 | goto bad_fork_free_pid; | |
2289 | ||
2290 | pidfd = retval; | |
6fd2fe49 AV |
2291 | |
2292 | pidfile = anon_inode_getfile("[pidfd]", &pidfd_fops, pid, | |
2293 | O_RDWR | O_CLOEXEC); | |
2294 | if (IS_ERR(pidfile)) { | |
2295 | put_unused_fd(pidfd); | |
28dd29c0 | 2296 | retval = PTR_ERR(pidfile); |
6fd2fe49 AV |
2297 | goto bad_fork_free_pid; |
2298 | } | |
2299 | get_pid(pid); /* held by pidfile now */ | |
2300 | ||
7f192e3c | 2301 | retval = put_user(pidfd, args->pidfd); |
b3e58382 CB |
2302 | if (retval) |
2303 | goto bad_fork_put_pidfd; | |
2304 | } | |
2305 | ||
73c10101 JA |
2306 | #ifdef CONFIG_BLOCK |
2307 | p->plug = NULL; | |
2308 | #endif | |
ba31c1a4 TG |
2309 | futex_init_task(p); |
2310 | ||
f9a3879a GM |
2311 | /* |
2312 | * sigaltstack should be cleared when sharing the same VM | |
2313 | */ | |
2314 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 2315 | sas_ss_reset(p); |
f9a3879a | 2316 | |
1da177e4 | 2317 | /* |
6580807d ON |
2318 | * Syscall tracing and stepping should be turned off in the |
2319 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 2320 | */ |
6580807d | 2321 | user_disable_single_step(p); |
64c19ba2 | 2322 | clear_task_syscall_work(p, SYSCALL_TRACE); |
64eb35f7 GKB |
2323 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) |
2324 | clear_task_syscall_work(p, SYSCALL_EMU); | |
ed75e8d5 | 2325 | #endif |
e02c9b0d | 2326 | clear_tsk_latency_tracing(p); |
1da177e4 | 2327 | |
1da177e4 | 2328 | /* ok, now we should be set up.. */ |
18c830df ON |
2329 | p->pid = pid_nr(pid); |
2330 | if (clone_flags & CLONE_THREAD) { | |
18c830df ON |
2331 | p->group_leader = current->group_leader; |
2332 | p->tgid = current->tgid; | |
2333 | } else { | |
18c830df ON |
2334 | p->group_leader = p; |
2335 | p->tgid = p->pid; | |
2336 | } | |
5f8aadd8 | 2337 | |
9d823e8f WF |
2338 | p->nr_dirtied = 0; |
2339 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 2340 | p->dirty_paused_when = 0; |
9d823e8f | 2341 | |
bb8cbbfe | 2342 | p->pdeath_signal = 0; |
47e65328 | 2343 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 2344 | p->task_works = NULL; |
ca7752ca | 2345 | clear_posix_cputimers_work(p); |
1da177e4 | 2346 | |
d741bf41 PZ |
2347 | #ifdef CONFIG_KRETPROBES |
2348 | p->kretprobe_instances.first = NULL; | |
2349 | #endif | |
54ecbe6f MH |
2350 | #ifdef CONFIG_RETHOOK |
2351 | p->rethooks.first = NULL; | |
2352 | #endif | |
d741bf41 | 2353 | |
7e47682e AS |
2354 | /* |
2355 | * Ensure that the cgroup subsystem policies allow the new process to be | |
7b7b8a2c | 2356 | * forked. It should be noted that the new process's css_set can be changed |
7e47682e AS |
2357 | * between here and cgroup_post_fork() if an organisation operation is in |
2358 | * progress. | |
2359 | */ | |
ef2c41cf | 2360 | retval = cgroup_can_fork(p, args); |
7e47682e | 2361 | if (retval) |
5a5cf5cb | 2362 | goto bad_fork_put_pidfd; |
7e47682e | 2363 | |
b1e82065 PZ |
2364 | /* |
2365 | * Now that the cgroups are pinned, re-clone the parent cgroup and put | |
2366 | * the new task on the correct runqueue. All this *before* the task | |
2367 | * becomes visible. | |
2368 | * | |
2369 | * This isn't part of ->can_fork() because while the re-cloning is | |
2370 | * cgroup specific, it unconditionally needs to place the task on a | |
2371 | * runqueue. | |
2372 | */ | |
2373 | sched_cgroup_fork(p, args); | |
2374 | ||
7b558513 DH |
2375 | /* |
2376 | * From this point on we must avoid any synchronous user-space | |
2377 | * communication until we take the tasklist-lock. In particular, we do | |
2378 | * not want user-space to be able to predict the process start-time by | |
2379 | * stalling fork(2) after we recorded the start_time but before it is | |
2380 | * visible to the system. | |
2381 | */ | |
2382 | ||
2383 | p->start_time = ktime_get_ns(); | |
cf25e24d | 2384 | p->start_boottime = ktime_get_boottime_ns(); |
7b558513 | 2385 | |
18c830df ON |
2386 | /* |
2387 | * Make it visible to the rest of the system, but dont wake it up yet. | |
2388 | * Need tasklist lock for parent etc handling! | |
2389 | */ | |
1da177e4 LT |
2390 | write_lock_irq(&tasklist_lock); |
2391 | ||
1da177e4 | 2392 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 2393 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 2394 | p->real_parent = current->real_parent; |
2d5516cb | 2395 | p->parent_exec_id = current->parent_exec_id; |
b4e00444 EW |
2396 | if (clone_flags & CLONE_THREAD) |
2397 | p->exit_signal = -1; | |
2398 | else | |
2399 | p->exit_signal = current->group_leader->exit_signal; | |
2d5516cb | 2400 | } else { |
1da177e4 | 2401 | p->real_parent = current; |
2d5516cb | 2402 | p->parent_exec_id = current->self_exec_id; |
b4e00444 | 2403 | p->exit_signal = args->exit_signal; |
2d5516cb | 2404 | } |
1da177e4 | 2405 | |
d83a7cb3 JP |
2406 | klp_copy_process(p); |
2407 | ||
85dd3f61 PZ |
2408 | sched_core_fork(p); |
2409 | ||
3f17da69 | 2410 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 2411 | |
dbd95212 KC |
2412 | /* |
2413 | * Copy seccomp details explicitly here, in case they were changed | |
2414 | * before holding sighand lock. | |
2415 | */ | |
2416 | copy_seccomp(p); | |
2417 | ||
79257534 DBO |
2418 | rv_task_fork(p); |
2419 | ||
d7822b1e MD |
2420 | rseq_fork(p, clone_flags); |
2421 | ||
4ca1d3ee | 2422 | /* Don't start children in a dying pid namespace */ |
e8cfbc24 | 2423 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { |
3fd37226 KT |
2424 | retval = -ENOMEM; |
2425 | goto bad_fork_cancel_cgroup; | |
2426 | } | |
4a2c7a78 | 2427 | |
7673bf55 EB |
2428 | /* Let kill terminate clone/fork in the middle */ |
2429 | if (fatal_signal_pending(current)) { | |
2430 | retval = -EINTR; | |
2431 | goto bad_fork_cancel_cgroup; | |
2432 | } | |
2433 | ||
2c470475 | 2434 | init_task_pid_links(p); |
73b9ebfe | 2435 | if (likely(p->pid)) { |
4b9d33e6 | 2436 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 2437 | |
81907739 | 2438 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 2439 | if (thread_group_leader(p)) { |
6883f81a | 2440 | init_task_pid(p, PIDTYPE_TGID, pid); |
81907739 ON |
2441 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
2442 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
2443 | ||
1c4042c2 | 2444 | if (is_child_reaper(pid)) { |
17cf22c3 | 2445 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
2446 | p->signal->flags |= SIGNAL_UNKILLABLE; |
2447 | } | |
c3ad2c3b | 2448 | p->signal->shared_pending.signal = delayed.signal; |
9c9f4ded | 2449 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
2450 | /* |
2451 | * Inherit has_child_subreaper flag under the same | |
2452 | * tasklist_lock with adding child to the process tree | |
2453 | * for propagate_has_child_subreaper optimization. | |
2454 | */ | |
2455 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
2456 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 2457 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 2458 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
6883f81a | 2459 | attach_pid(p, PIDTYPE_TGID); |
81907739 ON |
2460 | attach_pid(p, PIDTYPE_PGID); |
2461 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 2462 | __this_cpu_inc(process_counts); |
80628ca0 ON |
2463 | } else { |
2464 | current->signal->nr_threads++; | |
2465 | atomic_inc(¤t->signal->live); | |
60d4de3f | 2466 | refcount_inc(¤t->signal->sigcnt); |
924de3b8 | 2467 | task_join_group_stop(p); |
80628ca0 ON |
2468 | list_add_tail_rcu(&p->thread_group, |
2469 | &p->group_leader->thread_group); | |
0c740d0a ON |
2470 | list_add_tail_rcu(&p->thread_node, |
2471 | &p->signal->thread_head); | |
73b9ebfe | 2472 | } |
81907739 | 2473 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 2474 | nr_threads++; |
1da177e4 | 2475 | } |
1da177e4 | 2476 | total_forks++; |
c3ad2c3b | 2477 | hlist_del_init(&delayed.node); |
3f17da69 | 2478 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 2479 | syscall_tracepoint_update(p); |
1da177e4 | 2480 | write_unlock_irq(&tasklist_lock); |
4af4206b | 2481 | |
ddc204b5 WL |
2482 | if (pidfile) |
2483 | fd_install(pidfd, pidfile); | |
2484 | ||
c13cf856 | 2485 | proc_fork_connector(p); |
b1e82065 | 2486 | sched_post_fork(p); |
ef2c41cf | 2487 | cgroup_post_fork(p, args); |
cdd6c482 | 2488 | perf_event_fork(p); |
43d2b113 KH |
2489 | |
2490 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 2491 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 2492 | |
67197a4f SB |
2493 | copy_oom_score_adj(clone_flags, p); |
2494 | ||
1da177e4 LT |
2495 | return p; |
2496 | ||
7e47682e | 2497 | bad_fork_cancel_cgroup: |
85dd3f61 | 2498 | sched_core_free(p); |
3fd37226 KT |
2499 | spin_unlock(¤t->sighand->siglock); |
2500 | write_unlock_irq(&tasklist_lock); | |
ef2c41cf | 2501 | cgroup_cancel_fork(p, args); |
b3e58382 | 2502 | bad_fork_put_pidfd: |
6fd2fe49 AV |
2503 | if (clone_flags & CLONE_PIDFD) { |
2504 | fput(pidfile); | |
2505 | put_unused_fd(pidfd); | |
2506 | } | |
425fb2b4 PE |
2507 | bad_fork_free_pid: |
2508 | if (pid != &init_struct_pid) | |
2509 | free_pid(pid); | |
0740aa5f JS |
2510 | bad_fork_cleanup_thread: |
2511 | exit_thread(p); | |
fd0928df | 2512 | bad_fork_cleanup_io: |
b69f2292 LR |
2513 | if (p->io_context) |
2514 | exit_io_context(p); | |
ab516013 | 2515 | bad_fork_cleanup_namespaces: |
444f378b | 2516 | exit_task_namespaces(p); |
1da177e4 | 2517 | bad_fork_cleanup_mm: |
c3f3ce04 AA |
2518 | if (p->mm) { |
2519 | mm_clear_owner(p->mm, p); | |
1da177e4 | 2520 | mmput(p->mm); |
c3f3ce04 | 2521 | } |
1da177e4 | 2522 | bad_fork_cleanup_signal: |
4ab6c083 | 2523 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 2524 | free_signal_struct(p->signal); |
1da177e4 | 2525 | bad_fork_cleanup_sighand: |
a7e5328a | 2526 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
2527 | bad_fork_cleanup_fs: |
2528 | exit_fs(p); /* blocking */ | |
2529 | bad_fork_cleanup_files: | |
2530 | exit_files(p); /* blocking */ | |
2531 | bad_fork_cleanup_semundo: | |
2532 | exit_sem(p); | |
e4e55b47 TH |
2533 | bad_fork_cleanup_security: |
2534 | security_task_free(p); | |
1da177e4 LT |
2535 | bad_fork_cleanup_audit: |
2536 | audit_free(p); | |
6c72e350 | 2537 | bad_fork_cleanup_perf: |
cdd6c482 | 2538 | perf_event_free_task(p); |
6c72e350 | 2539 | bad_fork_cleanup_policy: |
b09be676 | 2540 | lockdep_free_task(p); |
1da177e4 | 2541 | #ifdef CONFIG_NUMA |
f0be3d32 | 2542 | mpol_put(p->mempolicy); |
1da177e4 | 2543 | #endif |
ff8288ff | 2544 | bad_fork_cleanup_delayacct: |
35df17c5 | 2545 | delayacct_tsk_free(p); |
1da177e4 | 2546 | bad_fork_cleanup_count: |
21d1c5e3 | 2547 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); |
e0e81739 | 2548 | exit_creds(p); |
1da177e4 | 2549 | bad_fork_free: |
2f064a59 | 2550 | WRITE_ONCE(p->__state, TASK_DEAD); |
1a03d3f1 | 2551 | exit_task_stack_account(p); |
68f24b08 | 2552 | put_task_stack(p); |
c3f3ce04 | 2553 | delayed_free_task(p); |
fe7d37d1 | 2554 | fork_out: |
c3ad2c3b EB |
2555 | spin_lock_irq(¤t->sighand->siglock); |
2556 | hlist_del_init(&delayed.node); | |
2557 | spin_unlock_irq(¤t->sighand->siglock); | |
fe7d37d1 | 2558 | return ERR_PTR(retval); |
1da177e4 LT |
2559 | } |
2560 | ||
2c470475 | 2561 | static inline void init_idle_pids(struct task_struct *idle) |
f106eee1 ON |
2562 | { |
2563 | enum pid_type type; | |
2564 | ||
2565 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
2c470475 EB |
2566 | INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */ |
2567 | init_task_pid(idle, type, &init_struct_pid); | |
f106eee1 ON |
2568 | } |
2569 | } | |
2570 | ||
36cb0e1c EB |
2571 | static int idle_dummy(void *dummy) |
2572 | { | |
2573 | /* This function is never called */ | |
2574 | return 0; | |
2575 | } | |
2576 | ||
f1a0a376 | 2577 | struct task_struct * __init fork_idle(int cpu) |
1da177e4 | 2578 | { |
36c8b586 | 2579 | struct task_struct *task; |
7f192e3c | 2580 | struct kernel_clone_args args = { |
343f4c49 | 2581 | .flags = CLONE_VM, |
5bd2e97c EB |
2582 | .fn = &idle_dummy, |
2583 | .fn_arg = NULL, | |
343f4c49 | 2584 | .kthread = 1, |
36cb0e1c | 2585 | .idle = 1, |
7f192e3c CB |
2586 | }; |
2587 | ||
2588 | task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args); | |
f106eee1 | 2589 | if (!IS_ERR(task)) { |
2c470475 | 2590 | init_idle_pids(task); |
753ca4f3 | 2591 | init_idle(task, cpu); |
f106eee1 | 2592 | } |
73b9ebfe | 2593 | |
1da177e4 LT |
2594 | return task; |
2595 | } | |
2596 | ||
13585fa0 NA |
2597 | struct mm_struct *copy_init_mm(void) |
2598 | { | |
2599 | return dup_mm(NULL, &init_mm); | |
2600 | } | |
2601 | ||
cc440e87 JA |
2602 | /* |
2603 | * This is like kernel_clone(), but shaved down and tailored to just | |
2604 | * creating io_uring workers. It returns a created task, or an error pointer. | |
2605 | * The returned task is inactive, and the caller must fire it up through | |
2606 | * wake_up_new_task(p). All signals are blocked in the created task. | |
2607 | */ | |
2608 | struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) | |
2609 | { | |
2610 | unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD| | |
2611 | CLONE_IO; | |
2612 | struct kernel_clone_args args = { | |
2613 | .flags = ((lower_32_bits(flags) | CLONE_VM | | |
2614 | CLONE_UNTRACED) & ~CSIGNAL), | |
2615 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2616 | .fn = fn, |
2617 | .fn_arg = arg, | |
cc440e87 JA |
2618 | .io_thread = 1, |
2619 | }; | |
cc440e87 | 2620 | |
b16b3855 | 2621 | return copy_process(NULL, 0, node, &args); |
cc440e87 JA |
2622 | } |
2623 | ||
1da177e4 LT |
2624 | /* |
2625 | * Ok, this is the main fork-routine. | |
2626 | * | |
2627 | * It copies the process, and if successful kick-starts | |
2628 | * it and waits for it to finish using the VM if required. | |
a0eb9abd ES |
2629 | * |
2630 | * args->exit_signal is expected to be checked for sanity by the caller. | |
1da177e4 | 2631 | */ |
cad6967a | 2632 | pid_t kernel_clone(struct kernel_clone_args *args) |
1da177e4 | 2633 | { |
7f192e3c | 2634 | u64 clone_flags = args->flags; |
9f5325aa MPS |
2635 | struct completion vfork; |
2636 | struct pid *pid; | |
1da177e4 LT |
2637 | struct task_struct *p; |
2638 | int trace = 0; | |
cad6967a | 2639 | pid_t nr; |
1da177e4 | 2640 | |
3af8588c CB |
2641 | /* |
2642 | * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument | |
2643 | * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are | |
2644 | * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate | |
2645 | * field in struct clone_args and it still doesn't make sense to have | |
2646 | * them both point at the same memory location. Performing this check | |
2647 | * here has the advantage that we don't need to have a separate helper | |
2648 | * to check for legacy clone(). | |
2649 | */ | |
2650 | if ((args->flags & CLONE_PIDFD) && | |
2651 | (args->flags & CLONE_PARENT_SETTID) && | |
2652 | (args->pidfd == args->parent_tid)) | |
2653 | return -EINVAL; | |
2654 | ||
09a05394 | 2655 | /* |
4b9d33e6 TH |
2656 | * Determine whether and which event to report to ptracer. When |
2657 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
2658 | * requested, no event is reported; otherwise, report if the event | |
2659 | * for the type of forking is enabled. | |
09a05394 | 2660 | */ |
e80d6661 | 2661 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
2662 | if (clone_flags & CLONE_VFORK) |
2663 | trace = PTRACE_EVENT_VFORK; | |
7f192e3c | 2664 | else if (args->exit_signal != SIGCHLD) |
4b9d33e6 TH |
2665 | trace = PTRACE_EVENT_CLONE; |
2666 | else | |
2667 | trace = PTRACE_EVENT_FORK; | |
2668 | ||
2669 | if (likely(!ptrace_event_enabled(current, trace))) | |
2670 | trace = 0; | |
2671 | } | |
1da177e4 | 2672 | |
7f192e3c | 2673 | p = copy_process(NULL, trace, NUMA_NO_NODE, args); |
38addce8 | 2674 | add_latent_entropy(); |
9f5325aa MPS |
2675 | |
2676 | if (IS_ERR(p)) | |
2677 | return PTR_ERR(p); | |
2678 | ||
1da177e4 LT |
2679 | /* |
2680 | * Do this prior waking up the new thread - the thread pointer | |
2681 | * might get invalid after that point, if the thread exits quickly. | |
2682 | */ | |
9f5325aa | 2683 | trace_sched_process_fork(current, p); |
0a16b607 | 2684 | |
9f5325aa MPS |
2685 | pid = get_task_pid(p, PIDTYPE_PID); |
2686 | nr = pid_vnr(pid); | |
30e49c26 | 2687 | |
9f5325aa | 2688 | if (clone_flags & CLONE_PARENT_SETTID) |
7f192e3c | 2689 | put_user(nr, args->parent_tid); |
a6f5e063 | 2690 | |
9f5325aa MPS |
2691 | if (clone_flags & CLONE_VFORK) { |
2692 | p->vfork_done = &vfork; | |
2693 | init_completion(&vfork); | |
2694 | get_task_struct(p); | |
2695 | } | |
1da177e4 | 2696 | |
bd74fdae YZ |
2697 | if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) { |
2698 | /* lock the task to synchronize with memcg migration */ | |
2699 | task_lock(p); | |
2700 | lru_gen_add_mm(p->mm); | |
2701 | task_unlock(p); | |
2702 | } | |
2703 | ||
9f5325aa | 2704 | wake_up_new_task(p); |
09a05394 | 2705 | |
9f5325aa MPS |
2706 | /* forking complete and child started to run, tell ptracer */ |
2707 | if (unlikely(trace)) | |
2708 | ptrace_event_pid(trace, pid); | |
4e52365f | 2709 | |
9f5325aa MPS |
2710 | if (clone_flags & CLONE_VFORK) { |
2711 | if (!wait_for_vfork_done(p, &vfork)) | |
2712 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); | |
1da177e4 | 2713 | } |
9f5325aa MPS |
2714 | |
2715 | put_pid(pid); | |
92476d7f | 2716 | return nr; |
1da177e4 LT |
2717 | } |
2718 | ||
2aa3a7f8 AV |
2719 | /* |
2720 | * Create a kernel thread. | |
2721 | */ | |
2722 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2723 | { | |
7f192e3c | 2724 | struct kernel_clone_args args = { |
3f2c788a CB |
2725 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2726 | CLONE_UNTRACED) & ~CSIGNAL), | |
2727 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2728 | .fn = fn, |
2729 | .fn_arg = arg, | |
343f4c49 EB |
2730 | .kthread = 1, |
2731 | }; | |
2732 | ||
2733 | return kernel_clone(&args); | |
2734 | } | |
2735 | ||
2736 | /* | |
2737 | * Create a user mode thread. | |
2738 | */ | |
2739 | pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2aa3a7f8 | 2740 | { |
7f192e3c | 2741 | struct kernel_clone_args args = { |
3f2c788a CB |
2742 | .flags = ((lower_32_bits(flags) | CLONE_VM | |
2743 | CLONE_UNTRACED) & ~CSIGNAL), | |
2744 | .exit_signal = (lower_32_bits(flags) & CSIGNAL), | |
5bd2e97c EB |
2745 | .fn = fn, |
2746 | .fn_arg = arg, | |
7f192e3c CB |
2747 | }; |
2748 | ||
cad6967a | 2749 | return kernel_clone(&args); |
2aa3a7f8 | 2750 | } |
2aa3a7f8 | 2751 | |
d2125043 AV |
2752 | #ifdef __ARCH_WANT_SYS_FORK |
2753 | SYSCALL_DEFINE0(fork) | |
2754 | { | |
2755 | #ifdef CONFIG_MMU | |
7f192e3c CB |
2756 | struct kernel_clone_args args = { |
2757 | .exit_signal = SIGCHLD, | |
2758 | }; | |
2759 | ||
cad6967a | 2760 | return kernel_clone(&args); |
d2125043 AV |
2761 | #else |
2762 | /* can not support in nommu mode */ | |
5d59e182 | 2763 | return -EINVAL; |
d2125043 AV |
2764 | #endif |
2765 | } | |
2766 | #endif | |
2767 | ||
2768 | #ifdef __ARCH_WANT_SYS_VFORK | |
2769 | SYSCALL_DEFINE0(vfork) | |
2770 | { | |
7f192e3c CB |
2771 | struct kernel_clone_args args = { |
2772 | .flags = CLONE_VFORK | CLONE_VM, | |
2773 | .exit_signal = SIGCHLD, | |
2774 | }; | |
2775 | ||
cad6967a | 2776 | return kernel_clone(&args); |
d2125043 AV |
2777 | } |
2778 | #endif | |
2779 | ||
2780 | #ifdef __ARCH_WANT_SYS_CLONE | |
2781 | #ifdef CONFIG_CLONE_BACKWARDS | |
2782 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2783 | int __user *, parent_tidptr, | |
3033f14a | 2784 | unsigned long, tls, |
d2125043 AV |
2785 | int __user *, child_tidptr) |
2786 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
2787 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
2788 | int __user *, parent_tidptr, | |
2789 | int __user *, child_tidptr, | |
3033f14a | 2790 | unsigned long, tls) |
dfa9771a MS |
2791 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
2792 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2793 | int, stack_size, | |
2794 | int __user *, parent_tidptr, | |
2795 | int __user *, child_tidptr, | |
3033f14a | 2796 | unsigned long, tls) |
d2125043 AV |
2797 | #else |
2798 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2799 | int __user *, parent_tidptr, | |
2800 | int __user *, child_tidptr, | |
3033f14a | 2801 | unsigned long, tls) |
d2125043 AV |
2802 | #endif |
2803 | { | |
7f192e3c | 2804 | struct kernel_clone_args args = { |
3f2c788a | 2805 | .flags = (lower_32_bits(clone_flags) & ~CSIGNAL), |
7f192e3c CB |
2806 | .pidfd = parent_tidptr, |
2807 | .child_tid = child_tidptr, | |
2808 | .parent_tid = parent_tidptr, | |
3f2c788a | 2809 | .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL), |
7f192e3c CB |
2810 | .stack = newsp, |
2811 | .tls = tls, | |
2812 | }; | |
2813 | ||
cad6967a | 2814 | return kernel_clone(&args); |
7f192e3c | 2815 | } |
d68dbb0c | 2816 | #endif |
7f192e3c | 2817 | |
d68dbb0c | 2818 | #ifdef __ARCH_WANT_SYS_CLONE3 |
dd499f7a | 2819 | |
7f192e3c CB |
2820 | noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, |
2821 | struct clone_args __user *uargs, | |
f14c234b | 2822 | size_t usize) |
7f192e3c | 2823 | { |
f14c234b | 2824 | int err; |
7f192e3c | 2825 | struct clone_args args; |
49cb2fc4 | 2826 | pid_t *kset_tid = kargs->set_tid; |
7f192e3c | 2827 | |
a966dcfe ES |
2828 | BUILD_BUG_ON(offsetofend(struct clone_args, tls) != |
2829 | CLONE_ARGS_SIZE_VER0); | |
2830 | BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) != | |
2831 | CLONE_ARGS_SIZE_VER1); | |
2832 | BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != | |
2833 | CLONE_ARGS_SIZE_VER2); | |
2834 | BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); | |
2835 | ||
f14c234b | 2836 | if (unlikely(usize > PAGE_SIZE)) |
7f192e3c | 2837 | return -E2BIG; |
f14c234b | 2838 | if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) |
7f192e3c CB |
2839 | return -EINVAL; |
2840 | ||
f14c234b AS |
2841 | err = copy_struct_from_user(&args, sizeof(args), uargs, usize); |
2842 | if (err) | |
2843 | return err; | |
7f192e3c | 2844 | |
49cb2fc4 AR |
2845 | if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL)) |
2846 | return -EINVAL; | |
2847 | ||
2848 | if (unlikely(!args.set_tid && args.set_tid_size > 0)) | |
2849 | return -EINVAL; | |
2850 | ||
2851 | if (unlikely(args.set_tid && args.set_tid_size == 0)) | |
2852 | return -EINVAL; | |
2853 | ||
a0eb9abd ES |
2854 | /* |
2855 | * Verify that higher 32bits of exit_signal are unset and that | |
2856 | * it is a valid signal | |
2857 | */ | |
2858 | if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) || | |
2859 | !valid_signal(args.exit_signal))) | |
2860 | return -EINVAL; | |
2861 | ||
62173872 ES |
2862 | if ((args.flags & CLONE_INTO_CGROUP) && |
2863 | (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2)) | |
ef2c41cf CB |
2864 | return -EINVAL; |
2865 | ||
7f192e3c CB |
2866 | *kargs = (struct kernel_clone_args){ |
2867 | .flags = args.flags, | |
2868 | .pidfd = u64_to_user_ptr(args.pidfd), | |
2869 | .child_tid = u64_to_user_ptr(args.child_tid), | |
2870 | .parent_tid = u64_to_user_ptr(args.parent_tid), | |
2871 | .exit_signal = args.exit_signal, | |
2872 | .stack = args.stack, | |
2873 | .stack_size = args.stack_size, | |
2874 | .tls = args.tls, | |
49cb2fc4 | 2875 | .set_tid_size = args.set_tid_size, |
ef2c41cf | 2876 | .cgroup = args.cgroup, |
7f192e3c CB |
2877 | }; |
2878 | ||
49cb2fc4 AR |
2879 | if (args.set_tid && |
2880 | copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid), | |
2881 | (kargs->set_tid_size * sizeof(pid_t)))) | |
2882 | return -EFAULT; | |
2883 | ||
2884 | kargs->set_tid = kset_tid; | |
2885 | ||
7f192e3c CB |
2886 | return 0; |
2887 | } | |
2888 | ||
fa729c4d CB |
2889 | /** |
2890 | * clone3_stack_valid - check and prepare stack | |
2891 | * @kargs: kernel clone args | |
2892 | * | |
2893 | * Verify that the stack arguments userspace gave us are sane. | |
2894 | * In addition, set the stack direction for userspace since it's easy for us to | |
2895 | * determine. | |
2896 | */ | |
2897 | static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) | |
2898 | { | |
2899 | if (kargs->stack == 0) { | |
2900 | if (kargs->stack_size > 0) | |
2901 | return false; | |
2902 | } else { | |
2903 | if (kargs->stack_size == 0) | |
2904 | return false; | |
2905 | ||
2906 | if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) | |
2907 | return false; | |
2908 | ||
2909 | #if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64) | |
2910 | kargs->stack += kargs->stack_size; | |
2911 | #endif | |
2912 | } | |
2913 | ||
2914 | return true; | |
2915 | } | |
2916 | ||
2917 | static bool clone3_args_valid(struct kernel_clone_args *kargs) | |
7f192e3c | 2918 | { |
b612e5df | 2919 | /* Verify that no unknown flags are passed along. */ |
ef2c41cf CB |
2920 | if (kargs->flags & |
2921 | ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP)) | |
7f192e3c CB |
2922 | return false; |
2923 | ||
2924 | /* | |
a8ca6b13 XC |
2925 | * - make the CLONE_DETACHED bit reusable for clone3 |
2926 | * - make the CSIGNAL bits reusable for clone3 | |
7f192e3c CB |
2927 | */ |
2928 | if (kargs->flags & (CLONE_DETACHED | CSIGNAL)) | |
2929 | return false; | |
2930 | ||
b612e5df CB |
2931 | if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) == |
2932 | (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) | |
2933 | return false; | |
2934 | ||
7f192e3c CB |
2935 | if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) && |
2936 | kargs->exit_signal) | |
2937 | return false; | |
2938 | ||
fa729c4d CB |
2939 | if (!clone3_stack_valid(kargs)) |
2940 | return false; | |
2941 | ||
7f192e3c CB |
2942 | return true; |
2943 | } | |
2944 | ||
501bd016 CB |
2945 | /** |
2946 | * clone3 - create a new process with specific properties | |
2947 | * @uargs: argument structure | |
2948 | * @size: size of @uargs | |
2949 | * | |
2950 | * clone3() is the extensible successor to clone()/clone2(). | |
2951 | * It takes a struct as argument that is versioned by its size. | |
2952 | * | |
2953 | * Return: On success, a positive PID for the child process. | |
2954 | * On error, a negative errno number. | |
2955 | */ | |
7f192e3c CB |
2956 | SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) |
2957 | { | |
2958 | int err; | |
2959 | ||
2960 | struct kernel_clone_args kargs; | |
49cb2fc4 AR |
2961 | pid_t set_tid[MAX_PID_NS_LEVEL]; |
2962 | ||
2963 | kargs.set_tid = set_tid; | |
7f192e3c CB |
2964 | |
2965 | err = copy_clone_args_from_user(&kargs, uargs, size); | |
2966 | if (err) | |
2967 | return err; | |
2968 | ||
2969 | if (!clone3_args_valid(&kargs)) | |
2970 | return -EINVAL; | |
2971 | ||
cad6967a | 2972 | return kernel_clone(&kargs); |
d2125043 AV |
2973 | } |
2974 | #endif | |
2975 | ||
0f1b92cb ON |
2976 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
2977 | { | |
2978 | struct task_struct *leader, *parent, *child; | |
2979 | int res; | |
2980 | ||
2981 | read_lock(&tasklist_lock); | |
2982 | leader = top = top->group_leader; | |
2983 | down: | |
2984 | for_each_thread(leader, parent) { | |
2985 | list_for_each_entry(child, &parent->children, sibling) { | |
2986 | res = visitor(child, data); | |
2987 | if (res) { | |
2988 | if (res < 0) | |
2989 | goto out; | |
2990 | leader = child; | |
2991 | goto down; | |
2992 | } | |
2993 | up: | |
2994 | ; | |
2995 | } | |
2996 | } | |
2997 | ||
2998 | if (leader != top) { | |
2999 | child = leader; | |
3000 | parent = child->real_parent; | |
3001 | leader = parent->group_leader; | |
3002 | goto up; | |
3003 | } | |
3004 | out: | |
3005 | read_unlock(&tasklist_lock); | |
3006 | } | |
3007 | ||
5fd63b30 RT |
3008 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
3009 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
3010 | #endif | |
3011 | ||
51cc5068 | 3012 | static void sighand_ctor(void *data) |
aa1757f9 ON |
3013 | { |
3014 | struct sighand_struct *sighand = data; | |
3015 | ||
a35afb83 | 3016 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 3017 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
3018 | } |
3019 | ||
1da177e4 LT |
3020 | void __init proc_caches_init(void) |
3021 | { | |
c1a2f7f0 RR |
3022 | unsigned int mm_size; |
3023 | ||
1da177e4 LT |
3024 | sighand_cachep = kmem_cache_create("sighand_cache", |
3025 | sizeof(struct sighand_struct), 0, | |
5f0d5a3a | 3026 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| |
75f296d9 | 3027 | SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
3028 | signal_cachep = kmem_cache_create("signal_cache", |
3029 | sizeof(struct signal_struct), 0, | |
75f296d9 | 3030 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3031 | NULL); |
20c2df83 | 3032 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 3033 | sizeof(struct files_struct), 0, |
75f296d9 | 3034 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3035 | NULL); |
20c2df83 | 3036 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 3037 | sizeof(struct fs_struct), 0, |
75f296d9 | 3038 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
5d097056 | 3039 | NULL); |
c1a2f7f0 | 3040 | |
6345d24d | 3041 | /* |
c1a2f7f0 RR |
3042 | * The mm_cpumask is located at the end of mm_struct, and is |
3043 | * dynamically sized based on the maximum CPU number this system | |
3044 | * can have, taking hotplug into account (nr_cpu_ids). | |
6345d24d | 3045 | */ |
c1a2f7f0 RR |
3046 | mm_size = sizeof(struct mm_struct) + cpumask_size(); |
3047 | ||
07dcd7fe | 3048 | mm_cachep = kmem_cache_create_usercopy("mm_struct", |
c1a2f7f0 | 3049 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN, |
75f296d9 | 3050 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, |
07dcd7fe DW |
3051 | offsetof(struct mm_struct, saved_auxv), |
3052 | sizeof_field(struct mm_struct, saved_auxv), | |
5d097056 VD |
3053 | NULL); |
3054 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 3055 | mmap_init(); |
66577193 | 3056 | nsproxy_cache_init(); |
1da177e4 | 3057 | } |
cf2e340f | 3058 | |
cf2e340f | 3059 | /* |
9bfb23fc | 3060 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 3061 | */ |
9bfb23fc | 3062 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 3063 | { |
9bfb23fc ON |
3064 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
3065 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 3066 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
769071ac AV |
3067 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP| |
3068 | CLONE_NEWTIME)) | |
9bfb23fc | 3069 | return -EINVAL; |
cf2e340f | 3070 | /* |
12c641ab EB |
3071 | * Not implemented, but pretend it works if there is nothing |
3072 | * to unshare. Note that unsharing the address space or the | |
3073 | * signal handlers also need to unshare the signal queues (aka | |
3074 | * CLONE_THREAD). | |
cf2e340f | 3075 | */ |
9bfb23fc | 3076 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
3077 | if (!thread_group_empty(current)) |
3078 | return -EINVAL; | |
3079 | } | |
3080 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
d036bda7 | 3081 | if (refcount_read(¤t->sighand->count) > 1) |
12c641ab EB |
3082 | return -EINVAL; |
3083 | } | |
3084 | if (unshare_flags & CLONE_VM) { | |
3085 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
3086 | return -EINVAL; |
3087 | } | |
cf2e340f JD |
3088 | |
3089 | return 0; | |
3090 | } | |
3091 | ||
3092 | /* | |
99d1419d | 3093 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
3094 | */ |
3095 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
3096 | { | |
3097 | struct fs_struct *fs = current->fs; | |
3098 | ||
498052bb AV |
3099 | if (!(unshare_flags & CLONE_FS) || !fs) |
3100 | return 0; | |
3101 | ||
3102 | /* don't need lock here; in the worst case we'll do useless copy */ | |
3103 | if (fs->users == 1) | |
3104 | return 0; | |
3105 | ||
3106 | *new_fsp = copy_fs_struct(fs); | |
3107 | if (!*new_fsp) | |
3108 | return -ENOMEM; | |
cf2e340f JD |
3109 | |
3110 | return 0; | |
3111 | } | |
3112 | ||
cf2e340f | 3113 | /* |
a016f338 | 3114 | * Unshare file descriptor table if it is being shared |
cf2e340f | 3115 | */ |
60997c3d CB |
3116 | int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, |
3117 | struct files_struct **new_fdp) | |
cf2e340f JD |
3118 | { |
3119 | struct files_struct *fd = current->files; | |
a016f338 | 3120 | int error = 0; |
cf2e340f JD |
3121 | |
3122 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 | 3123 | (fd && atomic_read(&fd->count) > 1)) { |
60997c3d | 3124 | *new_fdp = dup_fd(fd, max_fds, &error); |
a016f338 JD |
3125 | if (!*new_fdp) |
3126 | return error; | |
3127 | } | |
cf2e340f JD |
3128 | |
3129 | return 0; | |
3130 | } | |
3131 | ||
cf2e340f JD |
3132 | /* |
3133 | * unshare allows a process to 'unshare' part of the process | |
3134 | * context which was originally shared using clone. copy_* | |
cad6967a | 3135 | * functions used by kernel_clone() cannot be used here directly |
cf2e340f JD |
3136 | * because they modify an inactive task_struct that is being |
3137 | * constructed. Here we are modifying the current, active, | |
3138 | * task_struct. | |
3139 | */ | |
9b32105e | 3140 | int ksys_unshare(unsigned long unshare_flags) |
cf2e340f | 3141 | { |
cf2e340f | 3142 | struct fs_struct *fs, *new_fs = NULL; |
ba1f70dd | 3143 | struct files_struct *new_fd = NULL; |
b2e0d987 | 3144 | struct cred *new_cred = NULL; |
cf7b708c | 3145 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 3146 | int do_sysvsem = 0; |
9bfb23fc | 3147 | int err; |
cf2e340f | 3148 | |
b2e0d987 | 3149 | /* |
faf00da5 EB |
3150 | * If unsharing a user namespace must also unshare the thread group |
3151 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
3152 | */ |
3153 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 3154 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
3155 | /* |
3156 | * If unsharing vm, must also unshare signal handlers. | |
3157 | */ | |
3158 | if (unshare_flags & CLONE_VM) | |
3159 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
3160 | /* |
3161 | * If unsharing a signal handlers, must also unshare the signal queues. | |
3162 | */ | |
3163 | if (unshare_flags & CLONE_SIGHAND) | |
3164 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
3165 | /* |
3166 | * If unsharing namespace, must also unshare filesystem information. | |
3167 | */ | |
3168 | if (unshare_flags & CLONE_NEWNS) | |
3169 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
3170 | |
3171 | err = check_unshare_flags(unshare_flags); | |
3172 | if (err) | |
3173 | goto bad_unshare_out; | |
6013f67f MS |
3174 | /* |
3175 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
3176 | * to a new ipc namespace, the semaphore arrays from the old | |
3177 | * namespace are unreachable. | |
3178 | */ | |
3179 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 3180 | do_sysvsem = 1; |
fb0a685c DRO |
3181 | err = unshare_fs(unshare_flags, &new_fs); |
3182 | if (err) | |
9bfb23fc | 3183 | goto bad_unshare_out; |
60997c3d | 3184 | err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd); |
fb0a685c | 3185 | if (err) |
9bfb23fc | 3186 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 3187 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 3188 | if (err) |
9edff4ab | 3189 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
3190 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
3191 | new_cred, new_fs); | |
3192 | if (err) | |
3193 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 3194 | |
905ae01c AG |
3195 | if (new_cred) { |
3196 | err = set_cred_ucounts(new_cred); | |
3197 | if (err) | |
3198 | goto bad_unshare_cleanup_cred; | |
3199 | } | |
3200 | ||
b2e0d987 | 3201 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
3202 | if (do_sysvsem) { |
3203 | /* | |
3204 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
3205 | */ | |
3206 | exit_sem(current); | |
3207 | } | |
ab602f79 JM |
3208 | if (unshare_flags & CLONE_NEWIPC) { |
3209 | /* Orphan segments in old ns (see sem above). */ | |
3210 | exit_shm(current); | |
3211 | shm_init_task(current); | |
3212 | } | |
ab516013 | 3213 | |
6f977e6b | 3214 | if (new_nsproxy) |
cf7b708c | 3215 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 3216 | |
cf7b708c PE |
3217 | task_lock(current); |
3218 | ||
cf2e340f JD |
3219 | if (new_fs) { |
3220 | fs = current->fs; | |
2a4419b5 | 3221 | spin_lock(&fs->lock); |
cf2e340f | 3222 | current->fs = new_fs; |
498052bb AV |
3223 | if (--fs->users) |
3224 | new_fs = NULL; | |
3225 | else | |
3226 | new_fs = fs; | |
2a4419b5 | 3227 | spin_unlock(&fs->lock); |
cf2e340f JD |
3228 | } |
3229 | ||
ba1f70dd RX |
3230 | if (new_fd) |
3231 | swap(current->files, new_fd); | |
cf2e340f JD |
3232 | |
3233 | task_unlock(current); | |
b2e0d987 EB |
3234 | |
3235 | if (new_cred) { | |
3236 | /* Install the new user namespace */ | |
3237 | commit_creds(new_cred); | |
3238 | new_cred = NULL; | |
3239 | } | |
cf2e340f JD |
3240 | } |
3241 | ||
e4222673 HB |
3242 | perf_event_namespaces(current); |
3243 | ||
b2e0d987 EB |
3244 | bad_unshare_cleanup_cred: |
3245 | if (new_cred) | |
3246 | put_cred(new_cred); | |
cf2e340f JD |
3247 | bad_unshare_cleanup_fd: |
3248 | if (new_fd) | |
3249 | put_files_struct(new_fd); | |
3250 | ||
cf2e340f JD |
3251 | bad_unshare_cleanup_fs: |
3252 | if (new_fs) | |
498052bb | 3253 | free_fs_struct(new_fs); |
cf2e340f | 3254 | |
cf2e340f JD |
3255 | bad_unshare_out: |
3256 | return err; | |
3257 | } | |
3b125388 | 3258 | |
9b32105e DB |
3259 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
3260 | { | |
3261 | return ksys_unshare(unshare_flags); | |
3262 | } | |
3263 | ||
3b125388 AV |
3264 | /* |
3265 | * Helper to unshare the files of the current task. | |
3266 | * We don't want to expose copy_files internals to | |
3267 | * the exec layer of the kernel. | |
3268 | */ | |
3269 | ||
1f702603 | 3270 | int unshare_files(void) |
3b125388 AV |
3271 | { |
3272 | struct task_struct *task = current; | |
1f702603 | 3273 | struct files_struct *old, *copy = NULL; |
3b125388 AV |
3274 | int error; |
3275 | ||
60997c3d | 3276 | error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); |
1f702603 | 3277 | if (error || !copy) |
3b125388 | 3278 | return error; |
1f702603 EB |
3279 | |
3280 | old = task->files; | |
3b125388 AV |
3281 | task_lock(task); |
3282 | task->files = copy; | |
3283 | task_unlock(task); | |
1f702603 | 3284 | put_files_struct(old); |
3b125388 AV |
3285 | return 0; |
3286 | } | |
16db3d3f HS |
3287 | |
3288 | int sysctl_max_threads(struct ctl_table *table, int write, | |
b0daa2c7 | 3289 | void *buffer, size_t *lenp, loff_t *ppos) |
16db3d3f HS |
3290 | { |
3291 | struct ctl_table t; | |
3292 | int ret; | |
3293 | int threads = max_threads; | |
b0f53dbc | 3294 | int min = 1; |
16db3d3f HS |
3295 | int max = MAX_THREADS; |
3296 | ||
3297 | t = *table; | |
3298 | t.data = &threads; | |
3299 | t.extra1 = &min; | |
3300 | t.extra2 = &max; | |
3301 | ||
3302 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
3303 | if (ret || !write) | |
3304 | return ret; | |
3305 | ||
b0f53dbc | 3306 | max_threads = threads; |
16db3d3f HS |
3307 | |
3308 | return 0; | |
3309 | } |