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