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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/fork.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'fork.c' contains the help-routines for the 'fork' system call | |
9 | * (see also entry.S and others). | |
10 | * Fork is rather simple, once you get the hang of it, but the memory | |
11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
12 | */ | |
13 | ||
1da177e4 | 14 | #include <linux/slab.h> |
4eb5aaa3 | 15 | #include <linux/sched/autogroup.h> |
6e84f315 | 16 | #include <linux/sched/mm.h> |
f7ccbae4 | 17 | #include <linux/sched/coredump.h> |
8703e8a4 | 18 | #include <linux/sched/user.h> |
6a3827d7 | 19 | #include <linux/sched/numa_balancing.h> |
03441a34 | 20 | #include <linux/sched/stat.h> |
29930025 | 21 | #include <linux/sched/task.h> |
68db0cf1 | 22 | #include <linux/sched/task_stack.h> |
037741a6 | 23 | #include <linux/rtmutex.h> |
1da177e4 LT |
24 | #include <linux/init.h> |
25 | #include <linux/unistd.h> | |
1da177e4 LT |
26 | #include <linux/module.h> |
27 | #include <linux/vmalloc.h> | |
28 | #include <linux/completion.h> | |
1da177e4 LT |
29 | #include <linux/personality.h> |
30 | #include <linux/mempolicy.h> | |
31 | #include <linux/sem.h> | |
32 | #include <linux/file.h> | |
9f3acc31 | 33 | #include <linux/fdtable.h> |
da9cbc87 | 34 | #include <linux/iocontext.h> |
1da177e4 LT |
35 | #include <linux/key.h> |
36 | #include <linux/binfmts.h> | |
37 | #include <linux/mman.h> | |
cddb8a5c | 38 | #include <linux/mmu_notifier.h> |
1da177e4 | 39 | #include <linux/fs.h> |
615d6e87 DB |
40 | #include <linux/mm.h> |
41 | #include <linux/vmacache.h> | |
ab516013 | 42 | #include <linux/nsproxy.h> |
c59ede7b | 43 | #include <linux/capability.h> |
1da177e4 | 44 | #include <linux/cpu.h> |
b4f48b63 | 45 | #include <linux/cgroup.h> |
1da177e4 | 46 | #include <linux/security.h> |
a1e78772 | 47 | #include <linux/hugetlb.h> |
e2cfabdf | 48 | #include <linux/seccomp.h> |
1da177e4 LT |
49 | #include <linux/swap.h> |
50 | #include <linux/syscalls.h> | |
51 | #include <linux/jiffies.h> | |
52 | #include <linux/futex.h> | |
8141c7f3 | 53 | #include <linux/compat.h> |
207205a2 | 54 | #include <linux/kthread.h> |
7c3ab738 | 55 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 56 | #include <linux/rcupdate.h> |
1da177e4 LT |
57 | #include <linux/ptrace.h> |
58 | #include <linux/mount.h> | |
59 | #include <linux/audit.h> | |
78fb7466 | 60 | #include <linux/memcontrol.h> |
f201ae23 | 61 | #include <linux/ftrace.h> |
5e2bf014 | 62 | #include <linux/proc_fs.h> |
1da177e4 LT |
63 | #include <linux/profile.h> |
64 | #include <linux/rmap.h> | |
f8af4da3 | 65 | #include <linux/ksm.h> |
1da177e4 | 66 | #include <linux/acct.h> |
893e26e6 | 67 | #include <linux/userfaultfd_k.h> |
8f0ab514 | 68 | #include <linux/tsacct_kern.h> |
9f46080c | 69 | #include <linux/cn_proc.h> |
ba96a0c8 | 70 | #include <linux/freezer.h> |
ca74e92b | 71 | #include <linux/delayacct.h> |
ad4ecbcb | 72 | #include <linux/taskstats_kern.h> |
0a425405 | 73 | #include <linux/random.h> |
522ed776 | 74 | #include <linux/tty.h> |
fd0928df | 75 | #include <linux/blkdev.h> |
5ad4e53b | 76 | #include <linux/fs_struct.h> |
7c9f8861 | 77 | #include <linux/magic.h> |
cdd6c482 | 78 | #include <linux/perf_event.h> |
42c4ab41 | 79 | #include <linux/posix-timers.h> |
8e7cac79 | 80 | #include <linux/user-return-notifier.h> |
3d5992d2 | 81 | #include <linux/oom.h> |
ba76149f | 82 | #include <linux/khugepaged.h> |
d80e731e | 83 | #include <linux/signalfd.h> |
0326f5a9 | 84 | #include <linux/uprobes.h> |
a27bb332 | 85 | #include <linux/aio.h> |
52f5684c | 86 | #include <linux/compiler.h> |
16db3d3f | 87 | #include <linux/sysctl.h> |
5c9a8750 | 88 | #include <linux/kcov.h> |
1da177e4 LT |
89 | |
90 | #include <asm/pgtable.h> | |
91 | #include <asm/pgalloc.h> | |
7c0f6ba6 | 92 | #include <linux/uaccess.h> |
1da177e4 LT |
93 | #include <asm/mmu_context.h> |
94 | #include <asm/cacheflush.h> | |
95 | #include <asm/tlbflush.h> | |
96 | ||
ad8d75ff SR |
97 | #include <trace/events/sched.h> |
98 | ||
43d2b113 KH |
99 | #define CREATE_TRACE_POINTS |
100 | #include <trace/events/task.h> | |
101 | ||
ac1b398d HS |
102 | /* |
103 | * Minimum number of threads to boot the kernel | |
104 | */ | |
105 | #define MIN_THREADS 20 | |
106 | ||
107 | /* | |
108 | * Maximum number of threads | |
109 | */ | |
110 | #define MAX_THREADS FUTEX_TID_MASK | |
111 | ||
1da177e4 LT |
112 | /* |
113 | * Protected counters by write_lock_irq(&tasklist_lock) | |
114 | */ | |
115 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 116 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 LT |
117 | |
118 | int max_threads; /* tunable limit on nr_threads */ | |
119 | ||
120 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
121 | ||
c59923a1 | 122 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
123 | |
124 | #ifdef CONFIG_PROVE_RCU | |
125 | int lockdep_tasklist_lock_is_held(void) | |
126 | { | |
127 | return lockdep_is_held(&tasklist_lock); | |
128 | } | |
129 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
130 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
131 | |
132 | int nr_processes(void) | |
133 | { | |
134 | int cpu; | |
135 | int total = 0; | |
136 | ||
1d510750 | 137 | for_each_possible_cpu(cpu) |
1da177e4 LT |
138 | total += per_cpu(process_counts, cpu); |
139 | ||
140 | return total; | |
141 | } | |
142 | ||
f19b9f74 AM |
143 | void __weak arch_release_task_struct(struct task_struct *tsk) |
144 | { | |
145 | } | |
146 | ||
f5e10287 | 147 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 148 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
149 | |
150 | static inline struct task_struct *alloc_task_struct_node(int node) | |
151 | { | |
152 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
153 | } | |
154 | ||
41101809 TG |
155 | static inline void free_task_struct(struct task_struct *tsk) |
156 | { | |
41101809 TG |
157 | kmem_cache_free(task_struct_cachep, tsk); |
158 | } | |
1da177e4 LT |
159 | #endif |
160 | ||
b235beea | 161 | void __weak arch_release_thread_stack(unsigned long *stack) |
f19b9f74 AM |
162 | { |
163 | } | |
164 | ||
b235beea | 165 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 166 | |
0d15d74a TG |
167 | /* |
168 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
169 | * kmemcache based allocator. | |
170 | */ | |
ba14a194 | 171 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) |
ac496bf4 AL |
172 | |
173 | #ifdef CONFIG_VMAP_STACK | |
174 | /* | |
175 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB | |
176 | * flush. Try to minimize the number of calls by caching stacks. | |
177 | */ | |
178 | #define NR_CACHED_STACKS 2 | |
179 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); | |
180 | #endif | |
181 | ||
ba14a194 | 182 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) |
b69c49b7 | 183 | { |
ba14a194 | 184 | #ifdef CONFIG_VMAP_STACK |
ac496bf4 AL |
185 | void *stack; |
186 | int i; | |
187 | ||
188 | local_irq_disable(); | |
189 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
190 | struct vm_struct *s = this_cpu_read(cached_stacks[i]); | |
191 | ||
192 | if (!s) | |
193 | continue; | |
194 | this_cpu_write(cached_stacks[i], NULL); | |
195 | ||
196 | tsk->stack_vm_area = s; | |
197 | local_irq_enable(); | |
198 | return s->addr; | |
199 | } | |
200 | local_irq_enable(); | |
201 | ||
202 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE, | |
203 | VMALLOC_START, VMALLOC_END, | |
204 | THREADINFO_GFP | __GFP_HIGHMEM, | |
205 | PAGE_KERNEL, | |
206 | 0, node, __builtin_return_address(0)); | |
ba14a194 AL |
207 | |
208 | /* | |
209 | * We can't call find_vm_area() in interrupt context, and | |
210 | * free_thread_stack() can be called in interrupt context, | |
211 | * so cache the vm_struct. | |
212 | */ | |
213 | if (stack) | |
214 | tsk->stack_vm_area = find_vm_area(stack); | |
215 | return stack; | |
216 | #else | |
4949148a VD |
217 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
218 | THREAD_SIZE_ORDER); | |
b6a84016 ED |
219 | |
220 | return page ? page_address(page) : NULL; | |
ba14a194 | 221 | #endif |
b69c49b7 FT |
222 | } |
223 | ||
ba14a194 | 224 | static inline void free_thread_stack(struct task_struct *tsk) |
b69c49b7 | 225 | { |
ac496bf4 AL |
226 | #ifdef CONFIG_VMAP_STACK |
227 | if (task_stack_vm_area(tsk)) { | |
228 | unsigned long flags; | |
229 | int i; | |
230 | ||
231 | local_irq_save(flags); | |
232 | for (i = 0; i < NR_CACHED_STACKS; i++) { | |
233 | if (this_cpu_read(cached_stacks[i])) | |
234 | continue; | |
235 | ||
236 | this_cpu_write(cached_stacks[i], tsk->stack_vm_area); | |
237 | local_irq_restore(flags); | |
238 | return; | |
239 | } | |
240 | local_irq_restore(flags); | |
241 | ||
0f110a9b | 242 | vfree_atomic(tsk->stack); |
ac496bf4 AL |
243 | return; |
244 | } | |
245 | #endif | |
246 | ||
247 | __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER); | |
b69c49b7 | 248 | } |
0d15d74a | 249 | # else |
b235beea | 250 | static struct kmem_cache *thread_stack_cache; |
0d15d74a | 251 | |
9521d399 | 252 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, |
0d15d74a TG |
253 | int node) |
254 | { | |
b235beea | 255 | return kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); |
0d15d74a TG |
256 | } |
257 | ||
ba14a194 | 258 | static void free_thread_stack(struct task_struct *tsk) |
0d15d74a | 259 | { |
ba14a194 | 260 | kmem_cache_free(thread_stack_cache, tsk->stack); |
0d15d74a TG |
261 | } |
262 | ||
b235beea | 263 | void thread_stack_cache_init(void) |
0d15d74a | 264 | { |
b235beea | 265 | thread_stack_cache = kmem_cache_create("thread_stack", THREAD_SIZE, |
0d15d74a | 266 | THREAD_SIZE, 0, NULL); |
b235beea | 267 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a TG |
268 | } |
269 | # endif | |
b69c49b7 FT |
270 | #endif |
271 | ||
1da177e4 | 272 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 273 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
274 | |
275 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 276 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
277 | |
278 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 279 | struct kmem_cache *files_cachep; |
1da177e4 LT |
280 | |
281 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 282 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
283 | |
284 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 285 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
286 | |
287 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 288 | static struct kmem_cache *mm_cachep; |
1da177e4 | 289 | |
ba14a194 | 290 | static void account_kernel_stack(struct task_struct *tsk, int account) |
c6a7f572 | 291 | { |
ba14a194 AL |
292 | void *stack = task_stack_page(tsk); |
293 | struct vm_struct *vm = task_stack_vm_area(tsk); | |
294 | ||
295 | BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); | |
296 | ||
297 | if (vm) { | |
298 | int i; | |
299 | ||
300 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); | |
301 | ||
302 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { | |
303 | mod_zone_page_state(page_zone(vm->pages[i]), | |
304 | NR_KERNEL_STACK_KB, | |
305 | PAGE_SIZE / 1024 * account); | |
306 | } | |
307 | ||
308 | /* All stack pages belong to the same memcg. */ | |
309 | memcg_kmem_update_page_stat(vm->pages[0], MEMCG_KERNEL_STACK_KB, | |
310 | account * (THREAD_SIZE / 1024)); | |
311 | } else { | |
312 | /* | |
313 | * All stack pages are in the same zone and belong to the | |
314 | * same memcg. | |
315 | */ | |
316 | struct page *first_page = virt_to_page(stack); | |
317 | ||
318 | mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, | |
319 | THREAD_SIZE / 1024 * account); | |
320 | ||
321 | memcg_kmem_update_page_stat(first_page, MEMCG_KERNEL_STACK_KB, | |
322 | account * (THREAD_SIZE / 1024)); | |
323 | } | |
c6a7f572 KM |
324 | } |
325 | ||
68f24b08 | 326 | static void release_task_stack(struct task_struct *tsk) |
1da177e4 | 327 | { |
405c0759 AL |
328 | if (WARN_ON(tsk->state != TASK_DEAD)) |
329 | return; /* Better to leak the stack than to free prematurely */ | |
330 | ||
ba14a194 | 331 | account_kernel_stack(tsk, -1); |
b235beea | 332 | arch_release_thread_stack(tsk->stack); |
ba14a194 | 333 | free_thread_stack(tsk); |
68f24b08 AL |
334 | tsk->stack = NULL; |
335 | #ifdef CONFIG_VMAP_STACK | |
336 | tsk->stack_vm_area = NULL; | |
337 | #endif | |
338 | } | |
339 | ||
340 | #ifdef CONFIG_THREAD_INFO_IN_TASK | |
341 | void put_task_stack(struct task_struct *tsk) | |
342 | { | |
343 | if (atomic_dec_and_test(&tsk->stack_refcount)) | |
344 | release_task_stack(tsk); | |
345 | } | |
346 | #endif | |
347 | ||
348 | void free_task(struct task_struct *tsk) | |
349 | { | |
350 | #ifndef CONFIG_THREAD_INFO_IN_TASK | |
351 | /* | |
352 | * The task is finally done with both the stack and thread_info, | |
353 | * so free both. | |
354 | */ | |
355 | release_task_stack(tsk); | |
356 | #else | |
357 | /* | |
358 | * If the task had a separate stack allocation, it should be gone | |
359 | * by now. | |
360 | */ | |
361 | WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0); | |
362 | #endif | |
23f78d4a | 363 | rt_mutex_debug_task_free(tsk); |
fb52607a | 364 | ftrace_graph_exit_task(tsk); |
e2cfabdf | 365 | put_seccomp_filter(tsk); |
f19b9f74 | 366 | arch_release_task_struct(tsk); |
1da5c46f ON |
367 | if (tsk->flags & PF_KTHREAD) |
368 | free_kthread_struct(tsk); | |
1da177e4 LT |
369 | free_task_struct(tsk); |
370 | } | |
371 | EXPORT_SYMBOL(free_task); | |
372 | ||
ea6d290c ON |
373 | static inline void free_signal_struct(struct signal_struct *sig) |
374 | { | |
97101eb4 | 375 | taskstats_tgid_free(sig); |
1c5354de | 376 | sched_autogroup_exit(sig); |
7283094e MH |
377 | /* |
378 | * __mmdrop is not safe to call from softirq context on x86 due to | |
379 | * pgd_dtor so postpone it to the async context | |
380 | */ | |
26db62f1 | 381 | if (sig->oom_mm) |
7283094e | 382 | mmdrop_async(sig->oom_mm); |
ea6d290c ON |
383 | kmem_cache_free(signal_cachep, sig); |
384 | } | |
385 | ||
386 | static inline void put_signal_struct(struct signal_struct *sig) | |
387 | { | |
1c5354de | 388 | if (atomic_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
389 | free_signal_struct(sig); |
390 | } | |
391 | ||
158d9ebd | 392 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 393 | { |
270f722d | 394 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
395 | WARN_ON(atomic_read(&tsk->usage)); |
396 | WARN_ON(tsk == current); | |
397 | ||
2e91fa7f | 398 | cgroup_free(tsk); |
156654f4 | 399 | task_numa_free(tsk); |
1a2a4d06 | 400 | security_task_free(tsk); |
e0e81739 | 401 | exit_creds(tsk); |
35df17c5 | 402 | delayacct_tsk_free(tsk); |
ea6d290c | 403 | put_signal_struct(tsk->signal); |
1da177e4 LT |
404 | |
405 | if (!profile_handoff_task(tsk)) | |
406 | free_task(tsk); | |
407 | } | |
77c100c8 | 408 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 409 | |
6c0a9fa6 | 410 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 411 | |
ff691f6e HS |
412 | /* |
413 | * set_max_threads | |
414 | */ | |
16db3d3f | 415 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 416 | { |
ac1b398d | 417 | u64 threads; |
ff691f6e HS |
418 | |
419 | /* | |
ac1b398d HS |
420 | * The number of threads shall be limited such that the thread |
421 | * structures may only consume a small part of the available memory. | |
ff691f6e | 422 | */ |
ac1b398d HS |
423 | if (fls64(totalram_pages) + fls64(PAGE_SIZE) > 64) |
424 | threads = MAX_THREADS; | |
425 | else | |
426 | threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE, | |
427 | (u64) THREAD_SIZE * 8UL); | |
428 | ||
16db3d3f HS |
429 | if (threads > max_threads_suggested) |
430 | threads = max_threads_suggested; | |
431 | ||
ac1b398d | 432 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
433 | } |
434 | ||
5aaeb5c0 IM |
435 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
436 | /* Initialized by the architecture: */ | |
437 | int arch_task_struct_size __read_mostly; | |
438 | #endif | |
0c8c0f03 | 439 | |
ff691f6e | 440 | void __init fork_init(void) |
1da177e4 | 441 | { |
25f9c081 | 442 | int i; |
f5e10287 | 443 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 | 444 | #ifndef ARCH_MIN_TASKALIGN |
e274795e | 445 | #define ARCH_MIN_TASKALIGN 0 |
1da177e4 | 446 | #endif |
95cb64c1 | 447 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN); |
e274795e | 448 | |
1da177e4 | 449 | /* create a slab on which task_structs can be allocated */ |
5d097056 | 450 | task_struct_cachep = kmem_cache_create("task_struct", |
e274795e | 451 | arch_task_struct_size, align, |
5d097056 | 452 | SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, NULL); |
1da177e4 LT |
453 | #endif |
454 | ||
61c4628b SS |
455 | /* do the arch specific task caches init */ |
456 | arch_task_cache_init(); | |
457 | ||
16db3d3f | 458 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
459 | |
460 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
461 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
462 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
463 | init_task.signal->rlim[RLIMIT_NPROC]; | |
b376c3e1 | 464 | |
25f9c081 EB |
465 | for (i = 0; i < UCOUNT_COUNTS; i++) { |
466 | init_user_ns.ucount_max[i] = max_threads/2; | |
467 | } | |
1da177e4 LT |
468 | } |
469 | ||
52f5684c | 470 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
471 | struct task_struct *src) |
472 | { | |
473 | *dst = *src; | |
474 | return 0; | |
475 | } | |
476 | ||
d4311ff1 AT |
477 | void set_task_stack_end_magic(struct task_struct *tsk) |
478 | { | |
479 | unsigned long *stackend; | |
480 | ||
481 | stackend = end_of_stack(tsk); | |
482 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
483 | } | |
484 | ||
725fc629 | 485 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
486 | { |
487 | struct task_struct *tsk; | |
b235beea | 488 | unsigned long *stack; |
ba14a194 | 489 | struct vm_struct *stack_vm_area; |
3e26c149 | 490 | int err; |
1da177e4 | 491 | |
725fc629 AK |
492 | if (node == NUMA_NO_NODE) |
493 | node = tsk_fork_get_node(orig); | |
504f52b5 | 494 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
495 | if (!tsk) |
496 | return NULL; | |
497 | ||
b235beea LT |
498 | stack = alloc_thread_stack_node(tsk, node); |
499 | if (!stack) | |
f19b9f74 | 500 | goto free_tsk; |
1da177e4 | 501 | |
ba14a194 AL |
502 | stack_vm_area = task_stack_vm_area(tsk); |
503 | ||
fb0a685c | 504 | err = arch_dup_task_struct(tsk, orig); |
ba14a194 AL |
505 | |
506 | /* | |
507 | * arch_dup_task_struct() clobbers the stack-related fields. Make | |
508 | * sure they're properly initialized before using any stack-related | |
509 | * functions again. | |
510 | */ | |
511 | tsk->stack = stack; | |
512 | #ifdef CONFIG_VMAP_STACK | |
513 | tsk->stack_vm_area = stack_vm_area; | |
514 | #endif | |
68f24b08 AL |
515 | #ifdef CONFIG_THREAD_INFO_IN_TASK |
516 | atomic_set(&tsk->stack_refcount, 1); | |
517 | #endif | |
ba14a194 | 518 | |
164c33c6 | 519 | if (err) |
b235beea | 520 | goto free_stack; |
164c33c6 | 521 | |
dbd95212 KC |
522 | #ifdef CONFIG_SECCOMP |
523 | /* | |
524 | * We must handle setting up seccomp filters once we're under | |
525 | * the sighand lock in case orig has changed between now and | |
526 | * then. Until then, filter must be NULL to avoid messing up | |
527 | * the usage counts on the error path calling free_task. | |
528 | */ | |
529 | tsk->seccomp.filter = NULL; | |
530 | #endif | |
87bec58a AM |
531 | |
532 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 533 | clear_user_return_notifier(tsk); |
f26f9aff | 534 | clear_tsk_need_resched(tsk); |
d4311ff1 | 535 | set_task_stack_end_magic(tsk); |
1da177e4 | 536 | |
0a425405 AV |
537 | #ifdef CONFIG_CC_STACKPROTECTOR |
538 | tsk->stack_canary = get_random_int(); | |
539 | #endif | |
540 | ||
fb0a685c DRO |
541 | /* |
542 | * One for us, one for whoever does the "release_task()" (usually | |
543 | * parent) | |
544 | */ | |
545 | atomic_set(&tsk->usage, 2); | |
6c5c9341 | 546 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 547 | tsk->btrace_seq = 0; |
6c5c9341 | 548 | #endif |
a0aa7f68 | 549 | tsk->splice_pipe = NULL; |
5640f768 | 550 | tsk->task_frag.page = NULL; |
093e5840 | 551 | tsk->wake_q.next = NULL; |
c6a7f572 | 552 | |
ba14a194 | 553 | account_kernel_stack(tsk, 1); |
c6a7f572 | 554 | |
5c9a8750 DV |
555 | kcov_task_init(tsk); |
556 | ||
1da177e4 | 557 | return tsk; |
61c4628b | 558 | |
b235beea | 559 | free_stack: |
ba14a194 | 560 | free_thread_stack(tsk); |
f19b9f74 | 561 | free_tsk: |
61c4628b SS |
562 | free_task_struct(tsk); |
563 | return NULL; | |
1da177e4 LT |
564 | } |
565 | ||
566 | #ifdef CONFIG_MMU | |
0766f788 ER |
567 | static __latent_entropy int dup_mmap(struct mm_struct *mm, |
568 | struct mm_struct *oldmm) | |
1da177e4 | 569 | { |
297c5eee | 570 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; |
1da177e4 LT |
571 | struct rb_node **rb_link, *rb_parent; |
572 | int retval; | |
573 | unsigned long charge; | |
893e26e6 | 574 | LIST_HEAD(uf); |
1da177e4 | 575 | |
32cdba1e | 576 | uprobe_start_dup_mmap(); |
7c051267 MH |
577 | if (down_write_killable(&oldmm->mmap_sem)) { |
578 | retval = -EINTR; | |
579 | goto fail_uprobe_end; | |
580 | } | |
ec8c0446 | 581 | flush_cache_dup_mm(oldmm); |
f8ac4ec9 | 582 | uprobe_dup_mmap(oldmm, mm); |
ad339451 IM |
583 | /* |
584 | * Not linked in yet - no deadlock potential: | |
585 | */ | |
586 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 587 | |
90f31d0e KK |
588 | /* No ordering required: file already has been exposed. */ |
589 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
590 | ||
4f7d4614 | 591 | mm->total_vm = oldmm->total_vm; |
84638335 | 592 | mm->data_vm = oldmm->data_vm; |
4f7d4614 VD |
593 | mm->exec_vm = oldmm->exec_vm; |
594 | mm->stack_vm = oldmm->stack_vm; | |
595 | ||
1da177e4 LT |
596 | rb_link = &mm->mm_rb.rb_node; |
597 | rb_parent = NULL; | |
598 | pprev = &mm->mmap; | |
f8af4da3 | 599 | retval = ksm_fork(mm, oldmm); |
ba76149f AA |
600 | if (retval) |
601 | goto out; | |
602 | retval = khugepaged_fork(mm, oldmm); | |
f8af4da3 HD |
603 | if (retval) |
604 | goto out; | |
1da177e4 | 605 | |
297c5eee | 606 | prev = NULL; |
fd3e42fc | 607 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
608 | struct file *file; |
609 | ||
610 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
84638335 | 611 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); |
1da177e4 LT |
612 | continue; |
613 | } | |
614 | charge = 0; | |
615 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
b2412b7f HS |
616 | unsigned long len = vma_pages(mpnt); |
617 | ||
191c5424 | 618 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ |
1da177e4 LT |
619 | goto fail_nomem; |
620 | charge = len; | |
621 | } | |
e94b1766 | 622 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
623 | if (!tmp) |
624 | goto fail_nomem; | |
625 | *tmp = *mpnt; | |
5beb4930 | 626 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
ef0855d3 ON |
627 | retval = vma_dup_policy(mpnt, tmp); |
628 | if (retval) | |
1da177e4 | 629 | goto fail_nomem_policy; |
a247c3a9 | 630 | tmp->vm_mm = mm; |
893e26e6 PE |
631 | retval = dup_userfaultfd(tmp, &uf); |
632 | if (retval) | |
633 | goto fail_nomem_anon_vma_fork; | |
5beb4930 RR |
634 | if (anon_vma_fork(tmp, mpnt)) |
635 | goto fail_nomem_anon_vma_fork; | |
893e26e6 | 636 | tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); |
297c5eee | 637 | tmp->vm_next = tmp->vm_prev = NULL; |
1da177e4 LT |
638 | file = tmp->vm_file; |
639 | if (file) { | |
496ad9aa | 640 | struct inode *inode = file_inode(file); |
b88ed205 HD |
641 | struct address_space *mapping = file->f_mapping; |
642 | ||
1da177e4 LT |
643 | get_file(file); |
644 | if (tmp->vm_flags & VM_DENYWRITE) | |
645 | atomic_dec(&inode->i_writecount); | |
83cde9e8 | 646 | i_mmap_lock_write(mapping); |
b88ed205 | 647 | if (tmp->vm_flags & VM_SHARED) |
4bb5f5d9 | 648 | atomic_inc(&mapping->i_mmap_writable); |
b88ed205 HD |
649 | flush_dcache_mmap_lock(mapping); |
650 | /* insert tmp into the share list, just after mpnt */ | |
27ba0644 KS |
651 | vma_interval_tree_insert_after(tmp, mpnt, |
652 | &mapping->i_mmap); | |
b88ed205 | 653 | flush_dcache_mmap_unlock(mapping); |
83cde9e8 | 654 | i_mmap_unlock_write(mapping); |
1da177e4 LT |
655 | } |
656 | ||
a1e78772 MG |
657 | /* |
658 | * Clear hugetlb-related page reserves for children. This only | |
659 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
660 | * are not guaranteed to succeed, even if read-only | |
661 | */ | |
662 | if (is_vm_hugetlb_page(tmp)) | |
663 | reset_vma_resv_huge_pages(tmp); | |
664 | ||
1da177e4 | 665 | /* |
7ee78232 | 666 | * Link in the new vma and copy the page table entries. |
1da177e4 | 667 | */ |
1da177e4 LT |
668 | *pprev = tmp; |
669 | pprev = &tmp->vm_next; | |
297c5eee LT |
670 | tmp->vm_prev = prev; |
671 | prev = tmp; | |
1da177e4 LT |
672 | |
673 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
674 | rb_link = &tmp->vm_rb.rb_right; | |
675 | rb_parent = &tmp->vm_rb; | |
676 | ||
677 | mm->map_count++; | |
0b0db14c | 678 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
679 | |
680 | if (tmp->vm_ops && tmp->vm_ops->open) | |
681 | tmp->vm_ops->open(tmp); | |
682 | ||
683 | if (retval) | |
684 | goto out; | |
685 | } | |
d6dd61c8 JF |
686 | /* a new mm has just been created */ |
687 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 688 | retval = 0; |
1da177e4 | 689 | out: |
7ee78232 | 690 | up_write(&mm->mmap_sem); |
fd3e42fc | 691 | flush_tlb_mm(oldmm); |
1da177e4 | 692 | up_write(&oldmm->mmap_sem); |
893e26e6 | 693 | dup_userfaultfd_complete(&uf); |
7c051267 | 694 | fail_uprobe_end: |
32cdba1e | 695 | uprobe_end_dup_mmap(); |
1da177e4 | 696 | return retval; |
5beb4930 | 697 | fail_nomem_anon_vma_fork: |
ef0855d3 | 698 | mpol_put(vma_policy(tmp)); |
1da177e4 LT |
699 | fail_nomem_policy: |
700 | kmem_cache_free(vm_area_cachep, tmp); | |
701 | fail_nomem: | |
702 | retval = -ENOMEM; | |
703 | vm_unacct_memory(charge); | |
704 | goto out; | |
705 | } | |
706 | ||
fb0a685c | 707 | static inline int mm_alloc_pgd(struct mm_struct *mm) |
1da177e4 LT |
708 | { |
709 | mm->pgd = pgd_alloc(mm); | |
710 | if (unlikely(!mm->pgd)) | |
711 | return -ENOMEM; | |
712 | return 0; | |
713 | } | |
714 | ||
fb0a685c | 715 | static inline void mm_free_pgd(struct mm_struct *mm) |
1da177e4 | 716 | { |
5e541973 | 717 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
718 | } |
719 | #else | |
90f31d0e KK |
720 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
721 | { | |
722 | down_write(&oldmm->mmap_sem); | |
723 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
724 | up_write(&oldmm->mmap_sem); | |
725 | return 0; | |
726 | } | |
1da177e4 LT |
727 | #define mm_alloc_pgd(mm) (0) |
728 | #define mm_free_pgd(mm) | |
729 | #endif /* CONFIG_MMU */ | |
730 | ||
23ff4440 | 731 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 732 | |
e94b1766 | 733 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
734 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
735 | ||
4cb0e11b HK |
736 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
737 | ||
738 | static int __init coredump_filter_setup(char *s) | |
739 | { | |
740 | default_dump_filter = | |
741 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
742 | MMF_DUMP_FILTER_MASK; | |
743 | return 1; | |
744 | } | |
745 | ||
746 | __setup("coredump_filter=", coredump_filter_setup); | |
747 | ||
1da177e4 LT |
748 | #include <linux/init_task.h> |
749 | ||
858f0993 AD |
750 | static void mm_init_aio(struct mm_struct *mm) |
751 | { | |
752 | #ifdef CONFIG_AIO | |
753 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 754 | mm->ioctx_table = NULL; |
858f0993 AD |
755 | #endif |
756 | } | |
757 | ||
33144e84 VD |
758 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
759 | { | |
760 | #ifdef CONFIG_MEMCG | |
761 | mm->owner = p; | |
762 | #endif | |
763 | } | |
764 | ||
bfedb589 EB |
765 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, |
766 | struct user_namespace *user_ns) | |
1da177e4 | 767 | { |
41f727fd VD |
768 | mm->mmap = NULL; |
769 | mm->mm_rb = RB_ROOT; | |
770 | mm->vmacache_seqnum = 0; | |
1da177e4 LT |
771 | atomic_set(&mm->mm_users, 1); |
772 | atomic_set(&mm->mm_count, 1); | |
773 | init_rwsem(&mm->mmap_sem); | |
774 | INIT_LIST_HEAD(&mm->mmlist); | |
999d9fc1 | 775 | mm->core_state = NULL; |
e1f56c89 | 776 | atomic_long_set(&mm->nr_ptes, 0); |
2d2f5119 | 777 | mm_nr_pmds_init(mm); |
41f727fd VD |
778 | mm->map_count = 0; |
779 | mm->locked_vm = 0; | |
ce65cefa | 780 | mm->pinned_vm = 0; |
d559db08 | 781 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 782 | spin_lock_init(&mm->page_table_lock); |
41f727fd | 783 | mm_init_cpumask(mm); |
858f0993 | 784 | mm_init_aio(mm); |
cf475ad2 | 785 | mm_init_owner(mm, p); |
41f727fd | 786 | mmu_notifier_mm_init(mm); |
20841405 | 787 | clear_tlb_flush_pending(mm); |
41f727fd VD |
788 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
789 | mm->pmd_huge_pte = NULL; | |
790 | #endif | |
1da177e4 | 791 | |
a0715cc2 AT |
792 | if (current->mm) { |
793 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
794 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
795 | } else { | |
796 | mm->flags = default_dump_filter; | |
1da177e4 | 797 | mm->def_flags = 0; |
a0715cc2 AT |
798 | } |
799 | ||
41f727fd VD |
800 | if (mm_alloc_pgd(mm)) |
801 | goto fail_nopgd; | |
802 | ||
803 | if (init_new_context(p, mm)) | |
804 | goto fail_nocontext; | |
78fb7466 | 805 | |
bfedb589 | 806 | mm->user_ns = get_user_ns(user_ns); |
41f727fd VD |
807 | return mm; |
808 | ||
809 | fail_nocontext: | |
810 | mm_free_pgd(mm); | |
811 | fail_nopgd: | |
1da177e4 LT |
812 | free_mm(mm); |
813 | return NULL; | |
814 | } | |
815 | ||
c3f0327f KK |
816 | static void check_mm(struct mm_struct *mm) |
817 | { | |
818 | int i; | |
819 | ||
820 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
821 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
822 | ||
823 | if (unlikely(x)) | |
824 | printk(KERN_ALERT "BUG: Bad rss-counter state " | |
825 | "mm:%p idx:%d val:%ld\n", mm, i, x); | |
826 | } | |
b30fe6c7 KS |
827 | |
828 | if (atomic_long_read(&mm->nr_ptes)) | |
829 | pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld\n", | |
830 | atomic_long_read(&mm->nr_ptes)); | |
831 | if (mm_nr_pmds(mm)) | |
832 | pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld\n", | |
833 | mm_nr_pmds(mm)); | |
834 | ||
e009bb30 | 835 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
96dad67f | 836 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); |
c3f0327f KK |
837 | #endif |
838 | } | |
839 | ||
1da177e4 LT |
840 | /* |
841 | * Allocate and initialize an mm_struct. | |
842 | */ | |
fb0a685c | 843 | struct mm_struct *mm_alloc(void) |
1da177e4 | 844 | { |
fb0a685c | 845 | struct mm_struct *mm; |
1da177e4 LT |
846 | |
847 | mm = allocate_mm(); | |
de03c72c KM |
848 | if (!mm) |
849 | return NULL; | |
850 | ||
851 | memset(mm, 0, sizeof(*mm)); | |
bfedb589 | 852 | return mm_init(mm, current, current_user_ns()); |
1da177e4 LT |
853 | } |
854 | ||
855 | /* | |
856 | * Called when the last reference to the mm | |
857 | * is dropped: either by a lazy thread or by | |
858 | * mmput. Free the page directory and the mm. | |
859 | */ | |
7ad5b3a5 | 860 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
861 | { |
862 | BUG_ON(mm == &init_mm); | |
863 | mm_free_pgd(mm); | |
864 | destroy_context(mm); | |
cddb8a5c | 865 | mmu_notifier_mm_destroy(mm); |
c3f0327f | 866 | check_mm(mm); |
bfedb589 | 867 | put_user_ns(mm->user_ns); |
1da177e4 LT |
868 | free_mm(mm); |
869 | } | |
6d4e4c4f | 870 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 | 871 | |
ec8d7c14 MH |
872 | static inline void __mmput(struct mm_struct *mm) |
873 | { | |
874 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
875 | ||
876 | uprobe_clear_state(mm); | |
877 | exit_aio(mm); | |
878 | ksm_exit(mm); | |
879 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
880 | exit_mmap(mm); | |
6fcb52a5 | 881 | mm_put_huge_zero_page(mm); |
ec8d7c14 MH |
882 | set_mm_exe_file(mm, NULL); |
883 | if (!list_empty(&mm->mmlist)) { | |
884 | spin_lock(&mmlist_lock); | |
885 | list_del(&mm->mmlist); | |
886 | spin_unlock(&mmlist_lock); | |
887 | } | |
888 | if (mm->binfmt) | |
889 | module_put(mm->binfmt->module); | |
862e3073 | 890 | set_bit(MMF_OOM_SKIP, &mm->flags); |
ec8d7c14 MH |
891 | mmdrop(mm); |
892 | } | |
893 | ||
1da177e4 LT |
894 | /* |
895 | * Decrement the use count and release all resources for an mm. | |
896 | */ | |
897 | void mmput(struct mm_struct *mm) | |
898 | { | |
0ae26f1b AM |
899 | might_sleep(); |
900 | ||
ec8d7c14 MH |
901 | if (atomic_dec_and_test(&mm->mm_users)) |
902 | __mmput(mm); | |
903 | } | |
904 | EXPORT_SYMBOL_GPL(mmput); | |
905 | ||
7ef949d7 | 906 | #ifdef CONFIG_MMU |
ec8d7c14 MH |
907 | static void mmput_async_fn(struct work_struct *work) |
908 | { | |
909 | struct mm_struct *mm = container_of(work, struct mm_struct, async_put_work); | |
910 | __mmput(mm); | |
911 | } | |
912 | ||
913 | void mmput_async(struct mm_struct *mm) | |
914 | { | |
1da177e4 | 915 | if (atomic_dec_and_test(&mm->mm_users)) { |
ec8d7c14 MH |
916 | INIT_WORK(&mm->async_put_work, mmput_async_fn); |
917 | schedule_work(&mm->async_put_work); | |
1da177e4 LT |
918 | } |
919 | } | |
7ef949d7 | 920 | #endif |
1da177e4 | 921 | |
90f31d0e KK |
922 | /** |
923 | * set_mm_exe_file - change a reference to the mm's executable file | |
924 | * | |
925 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
926 | * | |
6e399cd1 DB |
927 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
928 | * invocations: in mmput() nobody alive left, in execve task is single | |
929 | * threaded. sys_prctl(PR_SET_MM_MAP/EXE_FILE) also needs to set the | |
930 | * mm->exe_file, but does so without using set_mm_exe_file() in order | |
931 | * to do avoid the need for any locks. | |
90f31d0e | 932 | */ |
38646013 JS |
933 | void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
934 | { | |
6e399cd1 DB |
935 | struct file *old_exe_file; |
936 | ||
937 | /* | |
938 | * It is safe to dereference the exe_file without RCU as | |
939 | * this function is only called if nobody else can access | |
940 | * this mm -- see comment above for justification. | |
941 | */ | |
942 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 943 | |
38646013 JS |
944 | if (new_exe_file) |
945 | get_file(new_exe_file); | |
90f31d0e KK |
946 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
947 | if (old_exe_file) | |
948 | fput(old_exe_file); | |
38646013 JS |
949 | } |
950 | ||
90f31d0e KK |
951 | /** |
952 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
953 | * | |
954 | * Returns %NULL if mm has no associated executable file. | |
955 | * User must release file via fput(). | |
956 | */ | |
38646013 JS |
957 | struct file *get_mm_exe_file(struct mm_struct *mm) |
958 | { | |
959 | struct file *exe_file; | |
960 | ||
90f31d0e KK |
961 | rcu_read_lock(); |
962 | exe_file = rcu_dereference(mm->exe_file); | |
963 | if (exe_file && !get_file_rcu(exe_file)) | |
964 | exe_file = NULL; | |
965 | rcu_read_unlock(); | |
38646013 JS |
966 | return exe_file; |
967 | } | |
11163348 | 968 | EXPORT_SYMBOL(get_mm_exe_file); |
38646013 | 969 | |
cd81a917 MG |
970 | /** |
971 | * get_task_exe_file - acquire a reference to the task's executable file | |
972 | * | |
973 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
974 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
975 | * User must release file via fput(). | |
976 | */ | |
977 | struct file *get_task_exe_file(struct task_struct *task) | |
978 | { | |
979 | struct file *exe_file = NULL; | |
980 | struct mm_struct *mm; | |
981 | ||
982 | task_lock(task); | |
983 | mm = task->mm; | |
984 | if (mm) { | |
985 | if (!(task->flags & PF_KTHREAD)) | |
986 | exe_file = get_mm_exe_file(mm); | |
987 | } | |
988 | task_unlock(task); | |
989 | return exe_file; | |
990 | } | |
991 | EXPORT_SYMBOL(get_task_exe_file); | |
38646013 | 992 | |
1da177e4 LT |
993 | /** |
994 | * get_task_mm - acquire a reference to the task's mm | |
995 | * | |
246bb0b1 | 996 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
997 | * this kernel workthread has transiently adopted a user mm with use_mm, |
998 | * to do its AIO) is not set and if so returns a reference to it, after | |
999 | * bumping up the use count. User must release the mm via mmput() | |
1000 | * after use. Typically used by /proc and ptrace. | |
1001 | */ | |
1002 | struct mm_struct *get_task_mm(struct task_struct *task) | |
1003 | { | |
1004 | struct mm_struct *mm; | |
1005 | ||
1006 | task_lock(task); | |
1007 | mm = task->mm; | |
1008 | if (mm) { | |
246bb0b1 | 1009 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
1010 | mm = NULL; |
1011 | else | |
3fce371b | 1012 | mmget(mm); |
1da177e4 LT |
1013 | } |
1014 | task_unlock(task); | |
1015 | return mm; | |
1016 | } | |
1017 | EXPORT_SYMBOL_GPL(get_task_mm); | |
1018 | ||
8cdb878d CY |
1019 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
1020 | { | |
1021 | struct mm_struct *mm; | |
1022 | int err; | |
1023 | ||
1024 | err = mutex_lock_killable(&task->signal->cred_guard_mutex); | |
1025 | if (err) | |
1026 | return ERR_PTR(err); | |
1027 | ||
1028 | mm = get_task_mm(task); | |
1029 | if (mm && mm != current->mm && | |
1030 | !ptrace_may_access(task, mode)) { | |
1031 | mmput(mm); | |
1032 | mm = ERR_PTR(-EACCES); | |
1033 | } | |
1034 | mutex_unlock(&task->signal->cred_guard_mutex); | |
1035 | ||
1036 | return mm; | |
1037 | } | |
1038 | ||
57b59c4a | 1039 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 1040 | { |
d68b46fe | 1041 | struct completion *vfork; |
c415c3b4 | 1042 | |
d68b46fe ON |
1043 | task_lock(tsk); |
1044 | vfork = tsk->vfork_done; | |
1045 | if (likely(vfork)) { | |
1046 | tsk->vfork_done = NULL; | |
1047 | complete(vfork); | |
1048 | } | |
1049 | task_unlock(tsk); | |
1050 | } | |
1051 | ||
1052 | static int wait_for_vfork_done(struct task_struct *child, | |
1053 | struct completion *vfork) | |
1054 | { | |
1055 | int killed; | |
1056 | ||
1057 | freezer_do_not_count(); | |
1058 | killed = wait_for_completion_killable(vfork); | |
1059 | freezer_count(); | |
1060 | ||
1061 | if (killed) { | |
1062 | task_lock(child); | |
1063 | child->vfork_done = NULL; | |
1064 | task_unlock(child); | |
1065 | } | |
1066 | ||
1067 | put_task_struct(child); | |
1068 | return killed; | |
c415c3b4 ON |
1069 | } |
1070 | ||
1da177e4 LT |
1071 | /* Please note the differences between mmput and mm_release. |
1072 | * mmput is called whenever we stop holding onto a mm_struct, | |
1073 | * error success whatever. | |
1074 | * | |
1075 | * mm_release is called after a mm_struct has been removed | |
1076 | * from the current process. | |
1077 | * | |
1078 | * This difference is important for error handling, when we | |
1079 | * only half set up a mm_struct for a new process and need to restore | |
1080 | * the old one. Because we mmput the new mm_struct before | |
1081 | * restoring the old one. . . | |
1082 | * Eric Biederman 10 January 1998 | |
1083 | */ | |
1084 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
1085 | { | |
8141c7f3 LT |
1086 | /* Get rid of any futexes when releasing the mm */ |
1087 | #ifdef CONFIG_FUTEX | |
fc6b177d | 1088 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 1089 | exit_robust_list(tsk); |
fc6b177d PZ |
1090 | tsk->robust_list = NULL; |
1091 | } | |
8141c7f3 | 1092 | #ifdef CONFIG_COMPAT |
fc6b177d | 1093 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 1094 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
1095 | tsk->compat_robust_list = NULL; |
1096 | } | |
8141c7f3 | 1097 | #endif |
322a2c10 TG |
1098 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
1099 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
1100 | #endif |
1101 | ||
0326f5a9 SD |
1102 | uprobe_free_utask(tsk); |
1103 | ||
1da177e4 LT |
1104 | /* Get rid of any cached register state */ |
1105 | deactivate_mm(tsk, mm); | |
1106 | ||
fec1d011 | 1107 | /* |
735f2770 MH |
1108 | * Signal userspace if we're not exiting with a core dump |
1109 | * because we want to leave the value intact for debugging | |
1110 | * purposes. | |
fec1d011 | 1111 | */ |
9c8a8228 | 1112 | if (tsk->clear_child_tid) { |
735f2770 | 1113 | if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) && |
9c8a8228 ED |
1114 | atomic_read(&mm->mm_users) > 1) { |
1115 | /* | |
1116 | * We don't check the error code - if userspace has | |
1117 | * not set up a proper pointer then tough luck. | |
1118 | */ | |
1119 | put_user(0, tsk->clear_child_tid); | |
1120 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
1121 | 1, NULL, NULL, 0); | |
1122 | } | |
1da177e4 | 1123 | tsk->clear_child_tid = NULL; |
1da177e4 | 1124 | } |
f7505d64 KK |
1125 | |
1126 | /* | |
1127 | * All done, finally we can wake up parent and return this mm to him. | |
1128 | * Also kthread_stop() uses this completion for synchronization. | |
1129 | */ | |
1130 | if (tsk->vfork_done) | |
1131 | complete_vfork_done(tsk); | |
1da177e4 LT |
1132 | } |
1133 | ||
a0a7ec30 JD |
1134 | /* |
1135 | * Allocate a new mm structure and copy contents from the | |
1136 | * mm structure of the passed in task structure. | |
1137 | */ | |
ff252c1f | 1138 | static struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
1139 | { |
1140 | struct mm_struct *mm, *oldmm = current->mm; | |
1141 | int err; | |
1142 | ||
a0a7ec30 JD |
1143 | mm = allocate_mm(); |
1144 | if (!mm) | |
1145 | goto fail_nomem; | |
1146 | ||
1147 | memcpy(mm, oldmm, sizeof(*mm)); | |
1148 | ||
bfedb589 | 1149 | if (!mm_init(mm, tsk, mm->user_ns)) |
a0a7ec30 JD |
1150 | goto fail_nomem; |
1151 | ||
a0a7ec30 JD |
1152 | err = dup_mmap(mm, oldmm); |
1153 | if (err) | |
1154 | goto free_pt; | |
1155 | ||
1156 | mm->hiwater_rss = get_mm_rss(mm); | |
1157 | mm->hiwater_vm = mm->total_vm; | |
1158 | ||
801460d0 HS |
1159 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
1160 | goto free_pt; | |
1161 | ||
a0a7ec30 JD |
1162 | return mm; |
1163 | ||
1164 | free_pt: | |
801460d0 HS |
1165 | /* don't put binfmt in mmput, we haven't got module yet */ |
1166 | mm->binfmt = NULL; | |
a0a7ec30 JD |
1167 | mmput(mm); |
1168 | ||
1169 | fail_nomem: | |
1170 | return NULL; | |
a0a7ec30 JD |
1171 | } |
1172 | ||
fb0a685c | 1173 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1174 | { |
fb0a685c | 1175 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1176 | int retval; |
1177 | ||
1178 | tsk->min_flt = tsk->maj_flt = 0; | |
1179 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1180 | #ifdef CONFIG_DETECT_HUNG_TASK |
1181 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
1182 | #endif | |
1da177e4 LT |
1183 | |
1184 | tsk->mm = NULL; | |
1185 | tsk->active_mm = NULL; | |
1186 | ||
1187 | /* | |
1188 | * Are we cloning a kernel thread? | |
1189 | * | |
1190 | * We need to steal a active VM for that.. | |
1191 | */ | |
1192 | oldmm = current->mm; | |
1193 | if (!oldmm) | |
1194 | return 0; | |
1195 | ||
615d6e87 DB |
1196 | /* initialize the new vmacache entries */ |
1197 | vmacache_flush(tsk); | |
1198 | ||
1da177e4 | 1199 | if (clone_flags & CLONE_VM) { |
3fce371b | 1200 | mmget(oldmm); |
1da177e4 | 1201 | mm = oldmm; |
1da177e4 LT |
1202 | goto good_mm; |
1203 | } | |
1204 | ||
1205 | retval = -ENOMEM; | |
a0a7ec30 | 1206 | mm = dup_mm(tsk); |
1da177e4 LT |
1207 | if (!mm) |
1208 | goto fail_nomem; | |
1209 | ||
1da177e4 LT |
1210 | good_mm: |
1211 | tsk->mm = mm; | |
1212 | tsk->active_mm = mm; | |
1213 | return 0; | |
1214 | ||
1da177e4 LT |
1215 | fail_nomem: |
1216 | return retval; | |
1da177e4 LT |
1217 | } |
1218 | ||
a39bc516 | 1219 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1220 | { |
498052bb | 1221 | struct fs_struct *fs = current->fs; |
1da177e4 | 1222 | if (clone_flags & CLONE_FS) { |
498052bb | 1223 | /* tsk->fs is already what we want */ |
2a4419b5 | 1224 | spin_lock(&fs->lock); |
498052bb | 1225 | if (fs->in_exec) { |
2a4419b5 | 1226 | spin_unlock(&fs->lock); |
498052bb AV |
1227 | return -EAGAIN; |
1228 | } | |
1229 | fs->users++; | |
2a4419b5 | 1230 | spin_unlock(&fs->lock); |
1da177e4 LT |
1231 | return 0; |
1232 | } | |
498052bb | 1233 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1234 | if (!tsk->fs) |
1235 | return -ENOMEM; | |
1236 | return 0; | |
1237 | } | |
1238 | ||
fb0a685c | 1239 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1240 | { |
1241 | struct files_struct *oldf, *newf; | |
1242 | int error = 0; | |
1243 | ||
1244 | /* | |
1245 | * A background process may not have any files ... | |
1246 | */ | |
1247 | oldf = current->files; | |
1248 | if (!oldf) | |
1249 | goto out; | |
1250 | ||
1251 | if (clone_flags & CLONE_FILES) { | |
1252 | atomic_inc(&oldf->count); | |
1253 | goto out; | |
1254 | } | |
1255 | ||
a016f338 JD |
1256 | newf = dup_fd(oldf, &error); |
1257 | if (!newf) | |
1258 | goto out; | |
1259 | ||
1260 | tsk->files = newf; | |
1261 | error = 0; | |
1262 | out: | |
1263 | return error; | |
1264 | } | |
1265 | ||
fadad878 | 1266 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
1267 | { |
1268 | #ifdef CONFIG_BLOCK | |
1269 | struct io_context *ioc = current->io_context; | |
6e736be7 | 1270 | struct io_context *new_ioc; |
fd0928df JA |
1271 | |
1272 | if (!ioc) | |
1273 | return 0; | |
fadad878 JA |
1274 | /* |
1275 | * Share io context with parent, if CLONE_IO is set | |
1276 | */ | |
1277 | if (clone_flags & CLONE_IO) { | |
3d48749d TH |
1278 | ioc_task_link(ioc); |
1279 | tsk->io_context = ioc; | |
fadad878 | 1280 | } else if (ioprio_valid(ioc->ioprio)) { |
6e736be7 TH |
1281 | new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE); |
1282 | if (unlikely(!new_ioc)) | |
fd0928df JA |
1283 | return -ENOMEM; |
1284 | ||
6e736be7 | 1285 | new_ioc->ioprio = ioc->ioprio; |
11a3122f | 1286 | put_io_context(new_ioc); |
fd0928df JA |
1287 | } |
1288 | #endif | |
1289 | return 0; | |
1290 | } | |
1291 | ||
a39bc516 | 1292 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1293 | { |
1294 | struct sighand_struct *sig; | |
1295 | ||
60348802 | 1296 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
1297 | atomic_inc(¤t->sighand->count); |
1298 | return 0; | |
1299 | } | |
1300 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 1301 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
1302 | if (!sig) |
1303 | return -ENOMEM; | |
9d7fb042 | 1304 | |
1da177e4 LT |
1305 | atomic_set(&sig->count, 1); |
1306 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
1307 | return 0; | |
1308 | } | |
1309 | ||
a7e5328a | 1310 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1311 | { |
d80e731e ON |
1312 | if (atomic_dec_and_test(&sighand->count)) { |
1313 | signalfd_cleanup(sighand); | |
392809b2 ON |
1314 | /* |
1315 | * sighand_cachep is SLAB_DESTROY_BY_RCU so we can free it | |
1316 | * without an RCU grace period, see __lock_task_sighand(). | |
1317 | */ | |
c81addc9 | 1318 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1319 | } |
c81addc9 ON |
1320 | } |
1321 | ||
b18b6a9c | 1322 | #ifdef CONFIG_POSIX_TIMERS |
f06febc9 FM |
1323 | /* |
1324 | * Initialize POSIX timer handling for a thread group. | |
1325 | */ | |
1326 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1327 | { | |
78d7d407 JS |
1328 | unsigned long cpu_limit; |
1329 | ||
316c1608 | 1330 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
78d7d407 | 1331 | if (cpu_limit != RLIM_INFINITY) { |
ebd7e7fc | 1332 | sig->cputime_expires.prof_exp = cpu_limit * NSEC_PER_SEC; |
d5c373eb | 1333 | sig->cputimer.running = true; |
6279a751 ON |
1334 | } |
1335 | ||
f06febc9 FM |
1336 | /* The timer lists. */ |
1337 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
1338 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
1339 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
1340 | } | |
b18b6a9c NP |
1341 | #else |
1342 | static inline void posix_cpu_timers_init_group(struct signal_struct *sig) { } | |
1343 | #endif | |
f06febc9 | 1344 | |
a39bc516 | 1345 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1346 | { |
1347 | struct signal_struct *sig; | |
1da177e4 | 1348 | |
4ab6c083 | 1349 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1350 | return 0; |
490dea45 | 1351 | |
a56704ef | 1352 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1353 | tsk->signal = sig; |
1354 | if (!sig) | |
1355 | return -ENOMEM; | |
1356 | ||
b3ac022c | 1357 | sig->nr_threads = 1; |
1da177e4 | 1358 | atomic_set(&sig->live, 1); |
b3ac022c | 1359 | atomic_set(&sig->sigcnt, 1); |
0c740d0a ON |
1360 | |
1361 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1362 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1363 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1364 | ||
1da177e4 | 1365 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1366 | sig->curr_target = tsk; |
1da177e4 | 1367 | init_sigpending(&sig->shared_pending); |
e78c3496 | 1368 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1369 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1370 | |
baa73d9e | 1371 | #ifdef CONFIG_POSIX_TIMERS |
b18b6a9c | 1372 | INIT_LIST_HEAD(&sig->posix_timers); |
c9cb2e3d | 1373 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1374 | sig->real_timer.function = it_real_fn; |
baa73d9e | 1375 | #endif |
1da177e4 | 1376 | |
1da177e4 LT |
1377 | task_lock(current->group_leader); |
1378 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1379 | task_unlock(current->group_leader); | |
1380 | ||
6279a751 ON |
1381 | posix_cpu_timers_init_group(sig); |
1382 | ||
522ed776 | 1383 | tty_audit_fork(sig); |
5091faa4 | 1384 | sched_autogroup_fork(sig); |
522ed776 | 1385 | |
a63d83f4 | 1386 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1387 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1388 | |
9b1bf12d KM |
1389 | mutex_init(&sig->cred_guard_mutex); |
1390 | ||
1da177e4 LT |
1391 | return 0; |
1392 | } | |
1393 | ||
dbd95212 KC |
1394 | static void copy_seccomp(struct task_struct *p) |
1395 | { | |
1396 | #ifdef CONFIG_SECCOMP | |
1397 | /* | |
1398 | * Must be called with sighand->lock held, which is common to | |
1399 | * all threads in the group. Holding cred_guard_mutex is not | |
1400 | * needed because this new task is not yet running and cannot | |
1401 | * be racing exec. | |
1402 | */ | |
69f6a34b | 1403 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1404 | |
1405 | /* Ref-count the new filter user, and assign it. */ | |
1406 | get_seccomp_filter(current); | |
1407 | p->seccomp = current->seccomp; | |
1408 | ||
1409 | /* | |
1410 | * Explicitly enable no_new_privs here in case it got set | |
1411 | * between the task_struct being duplicated and holding the | |
1412 | * sighand lock. The seccomp state and nnp must be in sync. | |
1413 | */ | |
1414 | if (task_no_new_privs(current)) | |
1415 | task_set_no_new_privs(p); | |
1416 | ||
1417 | /* | |
1418 | * If the parent gained a seccomp mode after copying thread | |
1419 | * flags and between before we held the sighand lock, we have | |
1420 | * to manually enable the seccomp thread flag here. | |
1421 | */ | |
1422 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
1423 | set_tsk_thread_flag(p, TIF_SECCOMP); | |
1424 | #endif | |
1425 | } | |
1426 | ||
17da2bd9 | 1427 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1428 | { |
1429 | current->clear_child_tid = tidptr; | |
1430 | ||
b488893a | 1431 | return task_pid_vnr(current); |
1da177e4 LT |
1432 | } |
1433 | ||
a39bc516 | 1434 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1435 | { |
1d615482 | 1436 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1437 | #ifdef CONFIG_RT_MUTEXES |
fb00aca4 PZ |
1438 | p->pi_waiters = RB_ROOT; |
1439 | p->pi_waiters_leftmost = NULL; | |
23f78d4a | 1440 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1441 | #endif |
1442 | } | |
1443 | ||
b18b6a9c | 1444 | #ifdef CONFIG_POSIX_TIMERS |
f06febc9 FM |
1445 | /* |
1446 | * Initialize POSIX timer handling for a single task. | |
1447 | */ | |
1448 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
1449 | { | |
64861634 MS |
1450 | tsk->cputime_expires.prof_exp = 0; |
1451 | tsk->cputime_expires.virt_exp = 0; | |
f06febc9 FM |
1452 | tsk->cputime_expires.sched_exp = 0; |
1453 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
1454 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
1455 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
1456 | } | |
b18b6a9c NP |
1457 | #else |
1458 | static inline void posix_cpu_timers_init(struct task_struct *tsk) { } | |
1459 | #endif | |
f06febc9 | 1460 | |
81907739 ON |
1461 | static inline void |
1462 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1463 | { | |
1464 | task->pids[type].pid = pid; | |
1465 | } | |
1466 | ||
1da177e4 LT |
1467 | /* |
1468 | * This creates a new process as a copy of the old one, | |
1469 | * but does not actually start it yet. | |
1470 | * | |
1471 | * It copies the registers, and all the appropriate | |
1472 | * parts of the process environment (as per the clone | |
1473 | * flags). The actual kick-off is left to the caller. | |
1474 | */ | |
0766f788 ER |
1475 | static __latent_entropy struct task_struct *copy_process( |
1476 | unsigned long clone_flags, | |
36c8b586 | 1477 | unsigned long stack_start, |
36c8b586 | 1478 | unsigned long stack_size, |
36c8b586 | 1479 | int __user *child_tidptr, |
09a05394 | 1480 | struct pid *pid, |
3033f14a | 1481 | int trace, |
725fc629 AK |
1482 | unsigned long tls, |
1483 | int node) | |
1da177e4 LT |
1484 | { |
1485 | int retval; | |
a24efe62 | 1486 | struct task_struct *p; |
1da177e4 LT |
1487 | |
1488 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
1489 | return ERR_PTR(-EINVAL); | |
1490 | ||
e66eded8 EB |
1491 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
1492 | return ERR_PTR(-EINVAL); | |
1493 | ||
1da177e4 LT |
1494 | /* |
1495 | * Thread groups must share signals as well, and detached threads | |
1496 | * can only be started up within the thread group. | |
1497 | */ | |
1498 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1499 | return ERR_PTR(-EINVAL); | |
1500 | ||
1501 | /* | |
1502 | * Shared signal handlers imply shared VM. By way of the above, | |
1503 | * thread groups also imply shared VM. Blocking this case allows | |
1504 | * for various simplifications in other code. | |
1505 | */ | |
1506 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1507 | return ERR_PTR(-EINVAL); | |
1508 | ||
123be07b SB |
1509 | /* |
1510 | * Siblings of global init remain as zombies on exit since they are | |
1511 | * not reaped by their parent (swapper). To solve this and to avoid | |
1512 | * multi-rooted process trees, prevent global and container-inits | |
1513 | * from creating siblings. | |
1514 | */ | |
1515 | if ((clone_flags & CLONE_PARENT) && | |
1516 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1517 | return ERR_PTR(-EINVAL); | |
1518 | ||
8382fcac | 1519 | /* |
40a0d32d | 1520 | * If the new process will be in a different pid or user namespace |
faf00da5 | 1521 | * do not allow it to share a thread group with the forking task. |
8382fcac | 1522 | */ |
faf00da5 | 1523 | if (clone_flags & CLONE_THREAD) { |
40a0d32d ON |
1524 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
1525 | (task_active_pid_ns(current) != | |
1526 | current->nsproxy->pid_ns_for_children)) | |
1527 | return ERR_PTR(-EINVAL); | |
1528 | } | |
8382fcac | 1529 | |
1da177e4 LT |
1530 | retval = security_task_create(clone_flags); |
1531 | if (retval) | |
1532 | goto fork_out; | |
1533 | ||
1534 | retval = -ENOMEM; | |
725fc629 | 1535 | p = dup_task_struct(current, node); |
1da177e4 LT |
1536 | if (!p) |
1537 | goto fork_out; | |
1538 | ||
f7e8b616 SR |
1539 | ftrace_graph_init_task(p); |
1540 | ||
bea493a0 PZ |
1541 | rt_mutex_init_task(p); |
1542 | ||
d12c1a37 | 1543 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1544 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1545 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1546 | #endif | |
1da177e4 | 1547 | retval = -EAGAIN; |
3b11a1de | 1548 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1549 | task_rlimit(p, RLIMIT_NPROC)) { |
b57922b6 EP |
1550 | if (p->real_cred->user != INIT_USER && |
1551 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
1552 | goto bad_fork_free; |
1553 | } | |
72fa5997 | 1554 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 1555 | |
f1752eec DH |
1556 | retval = copy_creds(p, clone_flags); |
1557 | if (retval < 0) | |
1558 | goto bad_fork_free; | |
1da177e4 LT |
1559 | |
1560 | /* | |
1561 | * If multiple threads are within copy_process(), then this check | |
1562 | * triggers too late. This doesn't hurt, the check is only there | |
1563 | * to stop root fork bombs. | |
1564 | */ | |
04ec93fe | 1565 | retval = -EAGAIN; |
1da177e4 LT |
1566 | if (nr_threads >= max_threads) |
1567 | goto bad_fork_cleanup_count; | |
1568 | ||
ca74e92b | 1569 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
c1de45ca | 1570 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE); |
514ddb44 | 1571 | p->flags |= PF_FORKNOEXEC; |
1da177e4 LT |
1572 | INIT_LIST_HEAD(&p->children); |
1573 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1574 | rcu_copy_process(p); |
1da177e4 LT |
1575 | p->vfork_done = NULL; |
1576 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1577 | |
1da177e4 LT |
1578 | init_sigpending(&p->pending); |
1579 | ||
64861634 | 1580 | p->utime = p->stime = p->gtime = 0; |
40565b5a | 1581 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME |
64861634 | 1582 | p->utimescaled = p->stimescaled = 0; |
40565b5a | 1583 | #endif |
9d7fb042 PZ |
1584 | prev_cputime_init(&p->prev_cputime); |
1585 | ||
6a61671b | 1586 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
b7ce2277 | 1587 | seqcount_init(&p->vtime_seqcount); |
6a61671b | 1588 | p->vtime_snap = 0; |
7098c1ea | 1589 | p->vtime_snap_whence = VTIME_INACTIVE; |
6a61671b FW |
1590 | #endif |
1591 | ||
a3a2e76c KH |
1592 | #if defined(SPLIT_RSS_COUNTING) |
1593 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1594 | #endif | |
172ba844 | 1595 | |
6976675d AV |
1596 | p->default_timer_slack_ns = current->timer_slack_ns; |
1597 | ||
5995477a | 1598 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1599 | acct_clear_integrals(p); |
1600 | ||
f06febc9 | 1601 | posix_cpu_timers_init(p); |
1da177e4 | 1602 | |
ccbf62d8 | 1603 | p->start_time = ktime_get_ns(); |
57e0be04 | 1604 | p->real_start_time = ktime_get_boot_ns(); |
1da177e4 | 1605 | p->io_context = NULL; |
1da177e4 | 1606 | p->audit_context = NULL; |
b4f48b63 | 1607 | cgroup_fork(p); |
1da177e4 | 1608 | #ifdef CONFIG_NUMA |
846a16bf | 1609 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
1610 | if (IS_ERR(p->mempolicy)) { |
1611 | retval = PTR_ERR(p->mempolicy); | |
1612 | p->mempolicy = NULL; | |
e8604cb4 | 1613 | goto bad_fork_cleanup_threadgroup_lock; |
fb0a685c | 1614 | } |
1da177e4 | 1615 | #endif |
778d3b0f MH |
1616 | #ifdef CONFIG_CPUSETS |
1617 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
1618 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
cc9a6c87 | 1619 | seqcount_init(&p->mems_allowed_seq); |
778d3b0f | 1620 | #endif |
de30a2b3 IM |
1621 | #ifdef CONFIG_TRACE_IRQFLAGS |
1622 | p->irq_events = 0; | |
1623 | p->hardirqs_enabled = 0; | |
1624 | p->hardirq_enable_ip = 0; | |
1625 | p->hardirq_enable_event = 0; | |
1626 | p->hardirq_disable_ip = _THIS_IP_; | |
1627 | p->hardirq_disable_event = 0; | |
1628 | p->softirqs_enabled = 1; | |
1629 | p->softirq_enable_ip = _THIS_IP_; | |
1630 | p->softirq_enable_event = 0; | |
1631 | p->softirq_disable_ip = 0; | |
1632 | p->softirq_disable_event = 0; | |
1633 | p->hardirq_context = 0; | |
1634 | p->softirq_context = 0; | |
1635 | #endif | |
8bcbde54 DH |
1636 | |
1637 | p->pagefault_disabled = 0; | |
1638 | ||
fbb9ce95 IM |
1639 | #ifdef CONFIG_LOCKDEP |
1640 | p->lockdep_depth = 0; /* no locks held yet */ | |
1641 | p->curr_chain_key = 0; | |
1642 | p->lockdep_recursion = 0; | |
1643 | #endif | |
1da177e4 | 1644 | |
408894ee IM |
1645 | #ifdef CONFIG_DEBUG_MUTEXES |
1646 | p->blocked_on = NULL; /* not blocked yet */ | |
1647 | #endif | |
cafe5635 KO |
1648 | #ifdef CONFIG_BCACHE |
1649 | p->sequential_io = 0; | |
1650 | p->sequential_io_avg = 0; | |
1651 | #endif | |
0f481406 | 1652 | |
3c90e6e9 | 1653 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
1654 | retval = sched_fork(clone_flags, p); |
1655 | if (retval) | |
1656 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 1657 | |
cdd6c482 | 1658 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1659 | if (retval) |
1660 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
1661 | retval = audit_alloc(p); |
1662 | if (retval) | |
6c72e350 | 1663 | goto bad_fork_cleanup_perf; |
1da177e4 | 1664 | /* copy all the process information */ |
ab602f79 | 1665 | shm_init_task(p); |
fb0a685c DRO |
1666 | retval = copy_semundo(clone_flags, p); |
1667 | if (retval) | |
1da177e4 | 1668 | goto bad_fork_cleanup_audit; |
fb0a685c DRO |
1669 | retval = copy_files(clone_flags, p); |
1670 | if (retval) | |
1da177e4 | 1671 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
1672 | retval = copy_fs(clone_flags, p); |
1673 | if (retval) | |
1da177e4 | 1674 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
1675 | retval = copy_sighand(clone_flags, p); |
1676 | if (retval) | |
1da177e4 | 1677 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
1678 | retval = copy_signal(clone_flags, p); |
1679 | if (retval) | |
1da177e4 | 1680 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
1681 | retval = copy_mm(clone_flags, p); |
1682 | if (retval) | |
1da177e4 | 1683 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
1684 | retval = copy_namespaces(clone_flags, p); |
1685 | if (retval) | |
d84f4f99 | 1686 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
1687 | retval = copy_io(clone_flags, p); |
1688 | if (retval) | |
fd0928df | 1689 | goto bad_fork_cleanup_namespaces; |
3033f14a | 1690 | retval = copy_thread_tls(clone_flags, stack_start, stack_size, p, tls); |
1da177e4 | 1691 | if (retval) |
fd0928df | 1692 | goto bad_fork_cleanup_io; |
1da177e4 | 1693 | |
425fb2b4 | 1694 | if (pid != &init_struct_pid) { |
c2b1df2e | 1695 | pid = alloc_pid(p->nsproxy->pid_ns_for_children); |
35f71bc0 MH |
1696 | if (IS_ERR(pid)) { |
1697 | retval = PTR_ERR(pid); | |
0740aa5f | 1698 | goto bad_fork_cleanup_thread; |
35f71bc0 | 1699 | } |
425fb2b4 PE |
1700 | } |
1701 | ||
1da177e4 LT |
1702 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1703 | /* | |
1704 | * Clear TID on mm_release()? | |
1705 | */ | |
fb0a685c | 1706 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL; |
73c10101 JA |
1707 | #ifdef CONFIG_BLOCK |
1708 | p->plug = NULL; | |
1709 | #endif | |
42b2dd0a | 1710 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1711 | p->robust_list = NULL; |
1712 | #ifdef CONFIG_COMPAT | |
1713 | p->compat_robust_list = NULL; | |
1714 | #endif | |
c87e2837 IM |
1715 | INIT_LIST_HEAD(&p->pi_state_list); |
1716 | p->pi_state_cache = NULL; | |
42b2dd0a | 1717 | #endif |
f9a3879a GM |
1718 | /* |
1719 | * sigaltstack should be cleared when sharing the same VM | |
1720 | */ | |
1721 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 1722 | sas_ss_reset(p); |
f9a3879a | 1723 | |
1da177e4 | 1724 | /* |
6580807d ON |
1725 | * Syscall tracing and stepping should be turned off in the |
1726 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1727 | */ |
6580807d | 1728 | user_disable_single_step(p); |
1da177e4 | 1729 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1730 | #ifdef TIF_SYSCALL_EMU |
1731 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1732 | #endif | |
9745512c | 1733 | clear_all_latency_tracing(p); |
1da177e4 | 1734 | |
1da177e4 | 1735 | /* ok, now we should be set up.. */ |
18c830df ON |
1736 | p->pid = pid_nr(pid); |
1737 | if (clone_flags & CLONE_THREAD) { | |
5f8aadd8 | 1738 | p->exit_signal = -1; |
18c830df ON |
1739 | p->group_leader = current->group_leader; |
1740 | p->tgid = current->tgid; | |
1741 | } else { | |
1742 | if (clone_flags & CLONE_PARENT) | |
1743 | p->exit_signal = current->group_leader->exit_signal; | |
1744 | else | |
1745 | p->exit_signal = (clone_flags & CSIGNAL); | |
1746 | p->group_leader = p; | |
1747 | p->tgid = p->pid; | |
1748 | } | |
5f8aadd8 | 1749 | |
9d823e8f WF |
1750 | p->nr_dirtied = 0; |
1751 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 1752 | p->dirty_paused_when = 0; |
9d823e8f | 1753 | |
bb8cbbfe | 1754 | p->pdeath_signal = 0; |
47e65328 | 1755 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 1756 | p->task_works = NULL; |
1da177e4 | 1757 | |
780de9dd | 1758 | cgroup_threadgroup_change_begin(current); |
7e47682e AS |
1759 | /* |
1760 | * Ensure that the cgroup subsystem policies allow the new process to be | |
1761 | * forked. It should be noted the the new process's css_set can be changed | |
1762 | * between here and cgroup_post_fork() if an organisation operation is in | |
1763 | * progress. | |
1764 | */ | |
b53202e6 | 1765 | retval = cgroup_can_fork(p); |
7e47682e AS |
1766 | if (retval) |
1767 | goto bad_fork_free_pid; | |
1768 | ||
18c830df ON |
1769 | /* |
1770 | * Make it visible to the rest of the system, but dont wake it up yet. | |
1771 | * Need tasklist lock for parent etc handling! | |
1772 | */ | |
1da177e4 LT |
1773 | write_lock_irq(&tasklist_lock); |
1774 | ||
1da177e4 | 1775 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1776 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1777 | p->real_parent = current->real_parent; |
2d5516cb ON |
1778 | p->parent_exec_id = current->parent_exec_id; |
1779 | } else { | |
1da177e4 | 1780 | p->real_parent = current; |
2d5516cb ON |
1781 | p->parent_exec_id = current->self_exec_id; |
1782 | } | |
1da177e4 | 1783 | |
3f17da69 | 1784 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 1785 | |
dbd95212 KC |
1786 | /* |
1787 | * Copy seccomp details explicitly here, in case they were changed | |
1788 | * before holding sighand lock. | |
1789 | */ | |
1790 | copy_seccomp(p); | |
1791 | ||
4a2c7a78 ON |
1792 | /* |
1793 | * Process group and session signals need to be delivered to just the | |
1794 | * parent before the fork or both the parent and the child after the | |
1795 | * fork. Restart if a signal comes in before we add the new process to | |
1796 | * it's process group. | |
1797 | * A fatal signal pending means that current will exit, so the new | |
1798 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
fb0a685c | 1799 | */ |
23ff4440 | 1800 | recalc_sigpending(); |
4a2c7a78 ON |
1801 | if (signal_pending(current)) { |
1802 | spin_unlock(¤t->sighand->siglock); | |
1803 | write_unlock_irq(&tasklist_lock); | |
1804 | retval = -ERESTARTNOINTR; | |
7e47682e | 1805 | goto bad_fork_cancel_cgroup; |
4a2c7a78 ON |
1806 | } |
1807 | ||
73b9ebfe | 1808 | if (likely(p->pid)) { |
4b9d33e6 | 1809 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 1810 | |
81907739 | 1811 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1812 | if (thread_group_leader(p)) { |
81907739 ON |
1813 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1814 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
1815 | ||
1c4042c2 | 1816 | if (is_child_reaper(pid)) { |
17cf22c3 | 1817 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
1818 | p->signal->flags |= SIGNAL_UNKILLABLE; |
1819 | } | |
73b9ebfe | 1820 | |
fea9d175 | 1821 | p->signal->leader_pid = pid; |
9c9f4ded | 1822 | p->signal->tty = tty_kref_get(current->signal->tty); |
749860ce PT |
1823 | /* |
1824 | * Inherit has_child_subreaper flag under the same | |
1825 | * tasklist_lock with adding child to the process tree | |
1826 | * for propagate_has_child_subreaper optimization. | |
1827 | */ | |
1828 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || | |
1829 | p->real_parent->signal->is_child_subreaper; | |
9cd80bbb | 1830 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 1831 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
81907739 ON |
1832 | attach_pid(p, PIDTYPE_PGID); |
1833 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 1834 | __this_cpu_inc(process_counts); |
80628ca0 ON |
1835 | } else { |
1836 | current->signal->nr_threads++; | |
1837 | atomic_inc(¤t->signal->live); | |
1838 | atomic_inc(¤t->signal->sigcnt); | |
80628ca0 ON |
1839 | list_add_tail_rcu(&p->thread_group, |
1840 | &p->group_leader->thread_group); | |
0c740d0a ON |
1841 | list_add_tail_rcu(&p->thread_node, |
1842 | &p->signal->thread_head); | |
73b9ebfe | 1843 | } |
81907739 | 1844 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 1845 | nr_threads++; |
1da177e4 LT |
1846 | } |
1847 | ||
1da177e4 | 1848 | total_forks++; |
3f17da69 | 1849 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 1850 | syscall_tracepoint_update(p); |
1da177e4 | 1851 | write_unlock_irq(&tasklist_lock); |
4af4206b | 1852 | |
c13cf856 | 1853 | proc_fork_connector(p); |
b53202e6 | 1854 | cgroup_post_fork(p); |
780de9dd | 1855 | cgroup_threadgroup_change_end(current); |
cdd6c482 | 1856 | perf_event_fork(p); |
43d2b113 KH |
1857 | |
1858 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 1859 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 1860 | |
1da177e4 LT |
1861 | return p; |
1862 | ||
7e47682e | 1863 | bad_fork_cancel_cgroup: |
b53202e6 | 1864 | cgroup_cancel_fork(p); |
425fb2b4 | 1865 | bad_fork_free_pid: |
780de9dd | 1866 | cgroup_threadgroup_change_end(current); |
425fb2b4 PE |
1867 | if (pid != &init_struct_pid) |
1868 | free_pid(pid); | |
0740aa5f JS |
1869 | bad_fork_cleanup_thread: |
1870 | exit_thread(p); | |
fd0928df | 1871 | bad_fork_cleanup_io: |
b69f2292 LR |
1872 | if (p->io_context) |
1873 | exit_io_context(p); | |
ab516013 | 1874 | bad_fork_cleanup_namespaces: |
444f378b | 1875 | exit_task_namespaces(p); |
1da177e4 | 1876 | bad_fork_cleanup_mm: |
c9f01245 | 1877 | if (p->mm) |
1da177e4 LT |
1878 | mmput(p->mm); |
1879 | bad_fork_cleanup_signal: | |
4ab6c083 | 1880 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 1881 | free_signal_struct(p->signal); |
1da177e4 | 1882 | bad_fork_cleanup_sighand: |
a7e5328a | 1883 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1884 | bad_fork_cleanup_fs: |
1885 | exit_fs(p); /* blocking */ | |
1886 | bad_fork_cleanup_files: | |
1887 | exit_files(p); /* blocking */ | |
1888 | bad_fork_cleanup_semundo: | |
1889 | exit_sem(p); | |
1890 | bad_fork_cleanup_audit: | |
1891 | audit_free(p); | |
6c72e350 | 1892 | bad_fork_cleanup_perf: |
cdd6c482 | 1893 | perf_event_free_task(p); |
6c72e350 | 1894 | bad_fork_cleanup_policy: |
1da177e4 | 1895 | #ifdef CONFIG_NUMA |
f0be3d32 | 1896 | mpol_put(p->mempolicy); |
e8604cb4 | 1897 | bad_fork_cleanup_threadgroup_lock: |
1da177e4 | 1898 | #endif |
35df17c5 | 1899 | delayacct_tsk_free(p); |
1da177e4 | 1900 | bad_fork_cleanup_count: |
d84f4f99 | 1901 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1902 | exit_creds(p); |
1da177e4 | 1903 | bad_fork_free: |
405c0759 | 1904 | p->state = TASK_DEAD; |
68f24b08 | 1905 | put_task_stack(p); |
1da177e4 | 1906 | free_task(p); |
fe7d37d1 ON |
1907 | fork_out: |
1908 | return ERR_PTR(retval); | |
1da177e4 LT |
1909 | } |
1910 | ||
f106eee1 ON |
1911 | static inline void init_idle_pids(struct pid_link *links) |
1912 | { | |
1913 | enum pid_type type; | |
1914 | ||
1915 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
1916 | INIT_HLIST_NODE(&links[type].node); /* not really needed */ | |
1917 | links[type].pid = &init_struct_pid; | |
1918 | } | |
1919 | } | |
1920 | ||
0db0628d | 1921 | struct task_struct *fork_idle(int cpu) |
1da177e4 | 1922 | { |
36c8b586 | 1923 | struct task_struct *task; |
725fc629 AK |
1924 | task = copy_process(CLONE_VM, 0, 0, NULL, &init_struct_pid, 0, 0, |
1925 | cpu_to_node(cpu)); | |
f106eee1 ON |
1926 | if (!IS_ERR(task)) { |
1927 | init_idle_pids(task->pids); | |
753ca4f3 | 1928 | init_idle(task, cpu); |
f106eee1 | 1929 | } |
73b9ebfe | 1930 | |
1da177e4 LT |
1931 | return task; |
1932 | } | |
1933 | ||
1da177e4 LT |
1934 | /* |
1935 | * Ok, this is the main fork-routine. | |
1936 | * | |
1937 | * It copies the process, and if successful kick-starts | |
1938 | * it and waits for it to finish using the VM if required. | |
1939 | */ | |
3033f14a | 1940 | long _do_fork(unsigned long clone_flags, |
1da177e4 | 1941 | unsigned long stack_start, |
1da177e4 LT |
1942 | unsigned long stack_size, |
1943 | int __user *parent_tidptr, | |
3033f14a JT |
1944 | int __user *child_tidptr, |
1945 | unsigned long tls) | |
1da177e4 LT |
1946 | { |
1947 | struct task_struct *p; | |
1948 | int trace = 0; | |
92476d7f | 1949 | long nr; |
1da177e4 | 1950 | |
09a05394 | 1951 | /* |
4b9d33e6 TH |
1952 | * Determine whether and which event to report to ptracer. When |
1953 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
1954 | * requested, no event is reported; otherwise, report if the event | |
1955 | * for the type of forking is enabled. | |
09a05394 | 1956 | */ |
e80d6661 | 1957 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
1958 | if (clone_flags & CLONE_VFORK) |
1959 | trace = PTRACE_EVENT_VFORK; | |
1960 | else if ((clone_flags & CSIGNAL) != SIGCHLD) | |
1961 | trace = PTRACE_EVENT_CLONE; | |
1962 | else | |
1963 | trace = PTRACE_EVENT_FORK; | |
1964 | ||
1965 | if (likely(!ptrace_event_enabled(current, trace))) | |
1966 | trace = 0; | |
1967 | } | |
1da177e4 | 1968 | |
62e791c1 | 1969 | p = copy_process(clone_flags, stack_start, stack_size, |
725fc629 | 1970 | child_tidptr, NULL, trace, tls, NUMA_NO_NODE); |
38addce8 | 1971 | add_latent_entropy(); |
1da177e4 LT |
1972 | /* |
1973 | * Do this prior waking up the new thread - the thread pointer | |
1974 | * might get invalid after that point, if the thread exits quickly. | |
1975 | */ | |
1976 | if (!IS_ERR(p)) { | |
1977 | struct completion vfork; | |
4e52365f | 1978 | struct pid *pid; |
1da177e4 | 1979 | |
0a16b607 MD |
1980 | trace_sched_process_fork(current, p); |
1981 | ||
4e52365f MD |
1982 | pid = get_task_pid(p, PIDTYPE_PID); |
1983 | nr = pid_vnr(pid); | |
30e49c26 PE |
1984 | |
1985 | if (clone_flags & CLONE_PARENT_SETTID) | |
1986 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1987 | |
1da177e4 LT |
1988 | if (clone_flags & CLONE_VFORK) { |
1989 | p->vfork_done = &vfork; | |
1990 | init_completion(&vfork); | |
d68b46fe | 1991 | get_task_struct(p); |
1da177e4 LT |
1992 | } |
1993 | ||
3e51e3ed | 1994 | wake_up_new_task(p); |
1da177e4 | 1995 | |
4b9d33e6 TH |
1996 | /* forking complete and child started to run, tell ptracer */ |
1997 | if (unlikely(trace)) | |
4e52365f | 1998 | ptrace_event_pid(trace, pid); |
09a05394 | 1999 | |
1da177e4 | 2000 | if (clone_flags & CLONE_VFORK) { |
d68b46fe | 2001 | if (!wait_for_vfork_done(p, &vfork)) |
4e52365f | 2002 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); |
1da177e4 | 2003 | } |
4e52365f MD |
2004 | |
2005 | put_pid(pid); | |
1da177e4 | 2006 | } else { |
92476d7f | 2007 | nr = PTR_ERR(p); |
1da177e4 | 2008 | } |
92476d7f | 2009 | return nr; |
1da177e4 LT |
2010 | } |
2011 | ||
3033f14a JT |
2012 | #ifndef CONFIG_HAVE_COPY_THREAD_TLS |
2013 | /* For compatibility with architectures that call do_fork directly rather than | |
2014 | * using the syscall entry points below. */ | |
2015 | long do_fork(unsigned long clone_flags, | |
2016 | unsigned long stack_start, | |
2017 | unsigned long stack_size, | |
2018 | int __user *parent_tidptr, | |
2019 | int __user *child_tidptr) | |
2020 | { | |
2021 | return _do_fork(clone_flags, stack_start, stack_size, | |
2022 | parent_tidptr, child_tidptr, 0); | |
2023 | } | |
2024 | #endif | |
2025 | ||
2aa3a7f8 AV |
2026 | /* |
2027 | * Create a kernel thread. | |
2028 | */ | |
2029 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
2030 | { | |
3033f14a JT |
2031 | return _do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn, |
2032 | (unsigned long)arg, NULL, NULL, 0); | |
2aa3a7f8 | 2033 | } |
2aa3a7f8 | 2034 | |
d2125043 AV |
2035 | #ifdef __ARCH_WANT_SYS_FORK |
2036 | SYSCALL_DEFINE0(fork) | |
2037 | { | |
2038 | #ifdef CONFIG_MMU | |
3033f14a | 2039 | return _do_fork(SIGCHLD, 0, 0, NULL, NULL, 0); |
d2125043 AV |
2040 | #else |
2041 | /* can not support in nommu mode */ | |
5d59e182 | 2042 | return -EINVAL; |
d2125043 AV |
2043 | #endif |
2044 | } | |
2045 | #endif | |
2046 | ||
2047 | #ifdef __ARCH_WANT_SYS_VFORK | |
2048 | SYSCALL_DEFINE0(vfork) | |
2049 | { | |
3033f14a JT |
2050 | return _do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0, |
2051 | 0, NULL, NULL, 0); | |
d2125043 AV |
2052 | } |
2053 | #endif | |
2054 | ||
2055 | #ifdef __ARCH_WANT_SYS_CLONE | |
2056 | #ifdef CONFIG_CLONE_BACKWARDS | |
2057 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2058 | int __user *, parent_tidptr, | |
3033f14a | 2059 | unsigned long, tls, |
d2125043 AV |
2060 | int __user *, child_tidptr) |
2061 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
2062 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
2063 | int __user *, parent_tidptr, | |
2064 | int __user *, child_tidptr, | |
3033f14a | 2065 | unsigned long, tls) |
dfa9771a MS |
2066 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
2067 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2068 | int, stack_size, | |
2069 | int __user *, parent_tidptr, | |
2070 | int __user *, child_tidptr, | |
3033f14a | 2071 | unsigned long, tls) |
d2125043 AV |
2072 | #else |
2073 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
2074 | int __user *, parent_tidptr, | |
2075 | int __user *, child_tidptr, | |
3033f14a | 2076 | unsigned long, tls) |
d2125043 AV |
2077 | #endif |
2078 | { | |
3033f14a | 2079 | return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr, tls); |
d2125043 AV |
2080 | } |
2081 | #endif | |
2082 | ||
0f1b92cb ON |
2083 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data) |
2084 | { | |
2085 | struct task_struct *leader, *parent, *child; | |
2086 | int res; | |
2087 | ||
2088 | read_lock(&tasklist_lock); | |
2089 | leader = top = top->group_leader; | |
2090 | down: | |
2091 | for_each_thread(leader, parent) { | |
2092 | list_for_each_entry(child, &parent->children, sibling) { | |
2093 | res = visitor(child, data); | |
2094 | if (res) { | |
2095 | if (res < 0) | |
2096 | goto out; | |
2097 | leader = child; | |
2098 | goto down; | |
2099 | } | |
2100 | up: | |
2101 | ; | |
2102 | } | |
2103 | } | |
2104 | ||
2105 | if (leader != top) { | |
2106 | child = leader; | |
2107 | parent = child->real_parent; | |
2108 | leader = parent->group_leader; | |
2109 | goto up; | |
2110 | } | |
2111 | out: | |
2112 | read_unlock(&tasklist_lock); | |
2113 | } | |
2114 | ||
5fd63b30 RT |
2115 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
2116 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
2117 | #endif | |
2118 | ||
51cc5068 | 2119 | static void sighand_ctor(void *data) |
aa1757f9 ON |
2120 | { |
2121 | struct sighand_struct *sighand = data; | |
2122 | ||
a35afb83 | 2123 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 2124 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
2125 | } |
2126 | ||
1da177e4 LT |
2127 | void __init proc_caches_init(void) |
2128 | { | |
2129 | sighand_cachep = kmem_cache_create("sighand_cache", | |
2130 | sizeof(struct sighand_struct), 0, | |
2dff4405 | 2131 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
5d097056 | 2132 | SLAB_NOTRACK|SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
2133 | signal_cachep = kmem_cache_create("signal_cache", |
2134 | sizeof(struct signal_struct), 0, | |
5d097056 VD |
2135 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
2136 | NULL); | |
20c2df83 | 2137 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 2138 | sizeof(struct files_struct), 0, |
5d097056 VD |
2139 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
2140 | NULL); | |
20c2df83 | 2141 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 2142 | sizeof(struct fs_struct), 0, |
5d097056 VD |
2143 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
2144 | NULL); | |
6345d24d LT |
2145 | /* |
2146 | * FIXME! The "sizeof(struct mm_struct)" currently includes the | |
2147 | * whole struct cpumask for the OFFSTACK case. We could change | |
2148 | * this to *only* allocate as much of it as required by the | |
2149 | * maximum number of CPU's we can ever have. The cpumask_allocation | |
2150 | * is at the end of the structure, exactly for that reason. | |
2151 | */ | |
1da177e4 | 2152 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 2153 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
5d097056 VD |
2154 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
2155 | NULL); | |
2156 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 2157 | mmap_init(); |
66577193 | 2158 | nsproxy_cache_init(); |
1da177e4 | 2159 | } |
cf2e340f | 2160 | |
cf2e340f | 2161 | /* |
9bfb23fc | 2162 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 2163 | */ |
9bfb23fc | 2164 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 2165 | { |
9bfb23fc ON |
2166 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
2167 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 2168 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
a79a908f | 2169 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP)) |
9bfb23fc | 2170 | return -EINVAL; |
cf2e340f | 2171 | /* |
12c641ab EB |
2172 | * Not implemented, but pretend it works if there is nothing |
2173 | * to unshare. Note that unsharing the address space or the | |
2174 | * signal handlers also need to unshare the signal queues (aka | |
2175 | * CLONE_THREAD). | |
cf2e340f | 2176 | */ |
9bfb23fc | 2177 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
2178 | if (!thread_group_empty(current)) |
2179 | return -EINVAL; | |
2180 | } | |
2181 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
2182 | if (atomic_read(¤t->sighand->count) > 1) | |
2183 | return -EINVAL; | |
2184 | } | |
2185 | if (unshare_flags & CLONE_VM) { | |
2186 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
2187 | return -EINVAL; |
2188 | } | |
cf2e340f JD |
2189 | |
2190 | return 0; | |
2191 | } | |
2192 | ||
2193 | /* | |
99d1419d | 2194 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
2195 | */ |
2196 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
2197 | { | |
2198 | struct fs_struct *fs = current->fs; | |
2199 | ||
498052bb AV |
2200 | if (!(unshare_flags & CLONE_FS) || !fs) |
2201 | return 0; | |
2202 | ||
2203 | /* don't need lock here; in the worst case we'll do useless copy */ | |
2204 | if (fs->users == 1) | |
2205 | return 0; | |
2206 | ||
2207 | *new_fsp = copy_fs_struct(fs); | |
2208 | if (!*new_fsp) | |
2209 | return -ENOMEM; | |
cf2e340f JD |
2210 | |
2211 | return 0; | |
2212 | } | |
2213 | ||
cf2e340f | 2214 | /* |
a016f338 | 2215 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
2216 | */ |
2217 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
2218 | { | |
2219 | struct files_struct *fd = current->files; | |
a016f338 | 2220 | int error = 0; |
cf2e340f JD |
2221 | |
2222 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
2223 | (fd && atomic_read(&fd->count) > 1)) { |
2224 | *new_fdp = dup_fd(fd, &error); | |
2225 | if (!*new_fdp) | |
2226 | return error; | |
2227 | } | |
cf2e340f JD |
2228 | |
2229 | return 0; | |
2230 | } | |
2231 | ||
cf2e340f JD |
2232 | /* |
2233 | * unshare allows a process to 'unshare' part of the process | |
2234 | * context which was originally shared using clone. copy_* | |
2235 | * functions used by do_fork() cannot be used here directly | |
2236 | * because they modify an inactive task_struct that is being | |
2237 | * constructed. Here we are modifying the current, active, | |
2238 | * task_struct. | |
2239 | */ | |
6559eed8 | 2240 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f | 2241 | { |
cf2e340f | 2242 | struct fs_struct *fs, *new_fs = NULL; |
cf2e340f | 2243 | struct files_struct *fd, *new_fd = NULL; |
b2e0d987 | 2244 | struct cred *new_cred = NULL; |
cf7b708c | 2245 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 2246 | int do_sysvsem = 0; |
9bfb23fc | 2247 | int err; |
cf2e340f | 2248 | |
b2e0d987 | 2249 | /* |
faf00da5 EB |
2250 | * If unsharing a user namespace must also unshare the thread group |
2251 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
2252 | */ |
2253 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 2254 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
2255 | /* |
2256 | * If unsharing vm, must also unshare signal handlers. | |
2257 | */ | |
2258 | if (unshare_flags & CLONE_VM) | |
2259 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
2260 | /* |
2261 | * If unsharing a signal handlers, must also unshare the signal queues. | |
2262 | */ | |
2263 | if (unshare_flags & CLONE_SIGHAND) | |
2264 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
2265 | /* |
2266 | * If unsharing namespace, must also unshare filesystem information. | |
2267 | */ | |
2268 | if (unshare_flags & CLONE_NEWNS) | |
2269 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
2270 | |
2271 | err = check_unshare_flags(unshare_flags); | |
2272 | if (err) | |
2273 | goto bad_unshare_out; | |
6013f67f MS |
2274 | /* |
2275 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
2276 | * to a new ipc namespace, the semaphore arrays from the old | |
2277 | * namespace are unreachable. | |
2278 | */ | |
2279 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 2280 | do_sysvsem = 1; |
fb0a685c DRO |
2281 | err = unshare_fs(unshare_flags, &new_fs); |
2282 | if (err) | |
9bfb23fc | 2283 | goto bad_unshare_out; |
fb0a685c DRO |
2284 | err = unshare_fd(unshare_flags, &new_fd); |
2285 | if (err) | |
9bfb23fc | 2286 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 2287 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 2288 | if (err) |
9edff4ab | 2289 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
2290 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
2291 | new_cred, new_fs); | |
2292 | if (err) | |
2293 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 2294 | |
b2e0d987 | 2295 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
2296 | if (do_sysvsem) { |
2297 | /* | |
2298 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
2299 | */ | |
2300 | exit_sem(current); | |
2301 | } | |
ab602f79 JM |
2302 | if (unshare_flags & CLONE_NEWIPC) { |
2303 | /* Orphan segments in old ns (see sem above). */ | |
2304 | exit_shm(current); | |
2305 | shm_init_task(current); | |
2306 | } | |
ab516013 | 2307 | |
6f977e6b | 2308 | if (new_nsproxy) |
cf7b708c | 2309 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 2310 | |
cf7b708c PE |
2311 | task_lock(current); |
2312 | ||
cf2e340f JD |
2313 | if (new_fs) { |
2314 | fs = current->fs; | |
2a4419b5 | 2315 | spin_lock(&fs->lock); |
cf2e340f | 2316 | current->fs = new_fs; |
498052bb AV |
2317 | if (--fs->users) |
2318 | new_fs = NULL; | |
2319 | else | |
2320 | new_fs = fs; | |
2a4419b5 | 2321 | spin_unlock(&fs->lock); |
cf2e340f JD |
2322 | } |
2323 | ||
cf2e340f JD |
2324 | if (new_fd) { |
2325 | fd = current->files; | |
2326 | current->files = new_fd; | |
2327 | new_fd = fd; | |
2328 | } | |
2329 | ||
2330 | task_unlock(current); | |
b2e0d987 EB |
2331 | |
2332 | if (new_cred) { | |
2333 | /* Install the new user namespace */ | |
2334 | commit_creds(new_cred); | |
2335 | new_cred = NULL; | |
2336 | } | |
cf2e340f JD |
2337 | } |
2338 | ||
b2e0d987 EB |
2339 | bad_unshare_cleanup_cred: |
2340 | if (new_cred) | |
2341 | put_cred(new_cred); | |
cf2e340f JD |
2342 | bad_unshare_cleanup_fd: |
2343 | if (new_fd) | |
2344 | put_files_struct(new_fd); | |
2345 | ||
cf2e340f JD |
2346 | bad_unshare_cleanup_fs: |
2347 | if (new_fs) | |
498052bb | 2348 | free_fs_struct(new_fs); |
cf2e340f | 2349 | |
cf2e340f JD |
2350 | bad_unshare_out: |
2351 | return err; | |
2352 | } | |
3b125388 AV |
2353 | |
2354 | /* | |
2355 | * Helper to unshare the files of the current task. | |
2356 | * We don't want to expose copy_files internals to | |
2357 | * the exec layer of the kernel. | |
2358 | */ | |
2359 | ||
2360 | int unshare_files(struct files_struct **displaced) | |
2361 | { | |
2362 | struct task_struct *task = current; | |
50704516 | 2363 | struct files_struct *copy = NULL; |
3b125388 AV |
2364 | int error; |
2365 | ||
2366 | error = unshare_fd(CLONE_FILES, ©); | |
2367 | if (error || !copy) { | |
2368 | *displaced = NULL; | |
2369 | return error; | |
2370 | } | |
2371 | *displaced = task->files; | |
2372 | task_lock(task); | |
2373 | task->files = copy; | |
2374 | task_unlock(task); | |
2375 | return 0; | |
2376 | } | |
16db3d3f HS |
2377 | |
2378 | int sysctl_max_threads(struct ctl_table *table, int write, | |
2379 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2380 | { | |
2381 | struct ctl_table t; | |
2382 | int ret; | |
2383 | int threads = max_threads; | |
2384 | int min = MIN_THREADS; | |
2385 | int max = MAX_THREADS; | |
2386 | ||
2387 | t = *table; | |
2388 | t.data = &threads; | |
2389 | t.extra1 = &min; | |
2390 | t.extra2 = &max; | |
2391 | ||
2392 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2393 | if (ret || !write) | |
2394 | return ret; | |
2395 | ||
2396 | set_max_threads(threads); | |
2397 | ||
2398 | return 0; | |
2399 | } |