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