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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 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/unistd.h> | |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/completion.h> | |
1da177e4 LT |
20 | #include <linux/personality.h> |
21 | #include <linux/mempolicy.h> | |
22 | #include <linux/sem.h> | |
23 | #include <linux/file.h> | |
9f3acc31 | 24 | #include <linux/fdtable.h> |
da9cbc87 | 25 | #include <linux/iocontext.h> |
1da177e4 LT |
26 | #include <linux/key.h> |
27 | #include <linux/binfmts.h> | |
28 | #include <linux/mman.h> | |
cddb8a5c | 29 | #include <linux/mmu_notifier.h> |
1da177e4 | 30 | #include <linux/fs.h> |
615d6e87 DB |
31 | #include <linux/mm.h> |
32 | #include <linux/vmacache.h> | |
ab516013 | 33 | #include <linux/nsproxy.h> |
c59ede7b | 34 | #include <linux/capability.h> |
1da177e4 | 35 | #include <linux/cpu.h> |
b4f48b63 | 36 | #include <linux/cgroup.h> |
1da177e4 | 37 | #include <linux/security.h> |
a1e78772 | 38 | #include <linux/hugetlb.h> |
e2cfabdf | 39 | #include <linux/seccomp.h> |
1da177e4 LT |
40 | #include <linux/swap.h> |
41 | #include <linux/syscalls.h> | |
42 | #include <linux/jiffies.h> | |
43 | #include <linux/futex.h> | |
8141c7f3 | 44 | #include <linux/compat.h> |
207205a2 | 45 | #include <linux/kthread.h> |
7c3ab738 | 46 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 47 | #include <linux/rcupdate.h> |
1da177e4 LT |
48 | #include <linux/ptrace.h> |
49 | #include <linux/mount.h> | |
50 | #include <linux/audit.h> | |
78fb7466 | 51 | #include <linux/memcontrol.h> |
f201ae23 | 52 | #include <linux/ftrace.h> |
5e2bf014 | 53 | #include <linux/proc_fs.h> |
1da177e4 LT |
54 | #include <linux/profile.h> |
55 | #include <linux/rmap.h> | |
f8af4da3 | 56 | #include <linux/ksm.h> |
1da177e4 | 57 | #include <linux/acct.h> |
8f0ab514 | 58 | #include <linux/tsacct_kern.h> |
9f46080c | 59 | #include <linux/cn_proc.h> |
ba96a0c8 | 60 | #include <linux/freezer.h> |
ca74e92b | 61 | #include <linux/delayacct.h> |
ad4ecbcb | 62 | #include <linux/taskstats_kern.h> |
0a425405 | 63 | #include <linux/random.h> |
522ed776 | 64 | #include <linux/tty.h> |
fd0928df | 65 | #include <linux/blkdev.h> |
5ad4e53b | 66 | #include <linux/fs_struct.h> |
7c9f8861 | 67 | #include <linux/magic.h> |
cdd6c482 | 68 | #include <linux/perf_event.h> |
42c4ab41 | 69 | #include <linux/posix-timers.h> |
8e7cac79 | 70 | #include <linux/user-return-notifier.h> |
3d5992d2 | 71 | #include <linux/oom.h> |
ba76149f | 72 | #include <linux/khugepaged.h> |
d80e731e | 73 | #include <linux/signalfd.h> |
0326f5a9 | 74 | #include <linux/uprobes.h> |
a27bb332 | 75 | #include <linux/aio.h> |
52f5684c | 76 | #include <linux/compiler.h> |
16db3d3f | 77 | #include <linux/sysctl.h> |
5c9a8750 | 78 | #include <linux/kcov.h> |
1da177e4 LT |
79 | |
80 | #include <asm/pgtable.h> | |
81 | #include <asm/pgalloc.h> | |
82 | #include <asm/uaccess.h> | |
83 | #include <asm/mmu_context.h> | |
84 | #include <asm/cacheflush.h> | |
85 | #include <asm/tlbflush.h> | |
86 | ||
ad8d75ff SR |
87 | #include <trace/events/sched.h> |
88 | ||
43d2b113 KH |
89 | #define CREATE_TRACE_POINTS |
90 | #include <trace/events/task.h> | |
91 | ||
ac1b398d HS |
92 | /* |
93 | * Minimum number of threads to boot the kernel | |
94 | */ | |
95 | #define MIN_THREADS 20 | |
96 | ||
97 | /* | |
98 | * Maximum number of threads | |
99 | */ | |
100 | #define MAX_THREADS FUTEX_TID_MASK | |
101 | ||
1da177e4 LT |
102 | /* |
103 | * Protected counters by write_lock_irq(&tasklist_lock) | |
104 | */ | |
105 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 106 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 LT |
107 | |
108 | int max_threads; /* tunable limit on nr_threads */ | |
109 | ||
110 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
111 | ||
c59923a1 | 112 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
113 | |
114 | #ifdef CONFIG_PROVE_RCU | |
115 | int lockdep_tasklist_lock_is_held(void) | |
116 | { | |
117 | return lockdep_is_held(&tasklist_lock); | |
118 | } | |
119 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
120 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
121 | |
122 | int nr_processes(void) | |
123 | { | |
124 | int cpu; | |
125 | int total = 0; | |
126 | ||
1d510750 | 127 | for_each_possible_cpu(cpu) |
1da177e4 LT |
128 | total += per_cpu(process_counts, cpu); |
129 | ||
130 | return total; | |
131 | } | |
132 | ||
f19b9f74 AM |
133 | void __weak arch_release_task_struct(struct task_struct *tsk) |
134 | { | |
135 | } | |
136 | ||
f5e10287 | 137 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 138 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
139 | |
140 | static inline struct task_struct *alloc_task_struct_node(int node) | |
141 | { | |
142 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
143 | } | |
144 | ||
41101809 TG |
145 | static inline void free_task_struct(struct task_struct *tsk) |
146 | { | |
41101809 TG |
147 | kmem_cache_free(task_struct_cachep, tsk); |
148 | } | |
1da177e4 LT |
149 | #endif |
150 | ||
b235beea | 151 | void __weak arch_release_thread_stack(unsigned long *stack) |
f19b9f74 AM |
152 | { |
153 | } | |
154 | ||
b235beea | 155 | #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR |
41101809 | 156 | |
0d15d74a TG |
157 | /* |
158 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
159 | * kmemcache based allocator. | |
160 | */ | |
161 | # if THREAD_SIZE >= PAGE_SIZE | |
b235beea | 162 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, |
b6a84016 | 163 | int node) |
b69c49b7 | 164 | { |
4949148a VD |
165 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
166 | THREAD_SIZE_ORDER); | |
b6a84016 ED |
167 | |
168 | return page ? page_address(page) : NULL; | |
b69c49b7 FT |
169 | } |
170 | ||
b235beea | 171 | static inline void free_thread_stack(unsigned long *stack) |
b69c49b7 | 172 | { |
efdc9490 | 173 | __free_pages(virt_to_page(stack), THREAD_SIZE_ORDER); |
b69c49b7 | 174 | } |
0d15d74a | 175 | # else |
b235beea | 176 | static struct kmem_cache *thread_stack_cache; |
0d15d74a | 177 | |
9521d399 | 178 | static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, |
0d15d74a TG |
179 | int node) |
180 | { | |
b235beea | 181 | return kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); |
0d15d74a TG |
182 | } |
183 | ||
9521d399 | 184 | static void free_thread_stack(unsigned long *stack) |
0d15d74a | 185 | { |
b235beea | 186 | kmem_cache_free(thread_stack_cache, stack); |
0d15d74a TG |
187 | } |
188 | ||
b235beea | 189 | void thread_stack_cache_init(void) |
0d15d74a | 190 | { |
b235beea | 191 | thread_stack_cache = kmem_cache_create("thread_stack", THREAD_SIZE, |
0d15d74a | 192 | THREAD_SIZE, 0, NULL); |
b235beea | 193 | BUG_ON(thread_stack_cache == NULL); |
0d15d74a TG |
194 | } |
195 | # endif | |
b69c49b7 FT |
196 | #endif |
197 | ||
1da177e4 | 198 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 199 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
200 | |
201 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 202 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
203 | |
204 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 205 | struct kmem_cache *files_cachep; |
1da177e4 LT |
206 | |
207 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 208 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
209 | |
210 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 211 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
212 | |
213 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 214 | static struct kmem_cache *mm_cachep; |
1da177e4 | 215 | |
b235beea | 216 | static void account_kernel_stack(unsigned long *stack, int account) |
c6a7f572 | 217 | { |
efdc9490 AL |
218 | /* All stack pages are in the same zone and belong to the same memcg. */ |
219 | struct page *first_page = virt_to_page(stack); | |
c6a7f572 | 220 | |
efdc9490 | 221 | mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, |
d30dd8be | 222 | THREAD_SIZE / 1024 * account); |
efdc9490 AL |
223 | |
224 | memcg_kmem_update_page_stat( | |
225 | first_page, MEMCG_KERNEL_STACK_KB, | |
226 | account * (THREAD_SIZE / 1024)); | |
c6a7f572 KM |
227 | } |
228 | ||
1da177e4 LT |
229 | void free_task(struct task_struct *tsk) |
230 | { | |
c6a7f572 | 231 | account_kernel_stack(tsk->stack, -1); |
b235beea LT |
232 | arch_release_thread_stack(tsk->stack); |
233 | free_thread_stack(tsk->stack); | |
23f78d4a | 234 | rt_mutex_debug_task_free(tsk); |
fb52607a | 235 | ftrace_graph_exit_task(tsk); |
e2cfabdf | 236 | put_seccomp_filter(tsk); |
f19b9f74 | 237 | arch_release_task_struct(tsk); |
1da177e4 LT |
238 | free_task_struct(tsk); |
239 | } | |
240 | EXPORT_SYMBOL(free_task); | |
241 | ||
ea6d290c ON |
242 | static inline void free_signal_struct(struct signal_struct *sig) |
243 | { | |
97101eb4 | 244 | taskstats_tgid_free(sig); |
1c5354de | 245 | sched_autogroup_exit(sig); |
ea6d290c ON |
246 | kmem_cache_free(signal_cachep, sig); |
247 | } | |
248 | ||
249 | static inline void put_signal_struct(struct signal_struct *sig) | |
250 | { | |
1c5354de | 251 | if (atomic_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
252 | free_signal_struct(sig); |
253 | } | |
254 | ||
158d9ebd | 255 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 256 | { |
270f722d | 257 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
258 | WARN_ON(atomic_read(&tsk->usage)); |
259 | WARN_ON(tsk == current); | |
260 | ||
2e91fa7f | 261 | cgroup_free(tsk); |
156654f4 | 262 | task_numa_free(tsk); |
1a2a4d06 | 263 | security_task_free(tsk); |
e0e81739 | 264 | exit_creds(tsk); |
35df17c5 | 265 | delayacct_tsk_free(tsk); |
ea6d290c | 266 | put_signal_struct(tsk->signal); |
1da177e4 LT |
267 | |
268 | if (!profile_handoff_task(tsk)) | |
269 | free_task(tsk); | |
270 | } | |
77c100c8 | 271 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 272 | |
6c0a9fa6 | 273 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 274 | |
ff691f6e HS |
275 | /* |
276 | * set_max_threads | |
277 | */ | |
16db3d3f | 278 | static void set_max_threads(unsigned int max_threads_suggested) |
ff691f6e | 279 | { |
ac1b398d | 280 | u64 threads; |
ff691f6e HS |
281 | |
282 | /* | |
ac1b398d HS |
283 | * The number of threads shall be limited such that the thread |
284 | * structures may only consume a small part of the available memory. | |
ff691f6e | 285 | */ |
ac1b398d HS |
286 | if (fls64(totalram_pages) + fls64(PAGE_SIZE) > 64) |
287 | threads = MAX_THREADS; | |
288 | else | |
289 | threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE, | |
290 | (u64) THREAD_SIZE * 8UL); | |
291 | ||
16db3d3f HS |
292 | if (threads > max_threads_suggested) |
293 | threads = max_threads_suggested; | |
294 | ||
ac1b398d | 295 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); |
ff691f6e HS |
296 | } |
297 | ||
5aaeb5c0 IM |
298 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT |
299 | /* Initialized by the architecture: */ | |
300 | int arch_task_struct_size __read_mostly; | |
301 | #endif | |
0c8c0f03 | 302 | |
ff691f6e | 303 | void __init fork_init(void) |
1da177e4 | 304 | { |
f5e10287 | 305 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 LT |
306 | #ifndef ARCH_MIN_TASKALIGN |
307 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
308 | #endif | |
309 | /* create a slab on which task_structs can be allocated */ | |
5d097056 VD |
310 | task_struct_cachep = kmem_cache_create("task_struct", |
311 | arch_task_struct_size, ARCH_MIN_TASKALIGN, | |
312 | SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, NULL); | |
1da177e4 LT |
313 | #endif |
314 | ||
61c4628b SS |
315 | /* do the arch specific task caches init */ |
316 | arch_task_cache_init(); | |
317 | ||
16db3d3f | 318 | set_max_threads(MAX_THREADS); |
1da177e4 LT |
319 | |
320 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
321 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
322 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
323 | init_task.signal->rlim[RLIMIT_NPROC]; | |
324 | } | |
325 | ||
52f5684c | 326 | int __weak arch_dup_task_struct(struct task_struct *dst, |
61c4628b SS |
327 | struct task_struct *src) |
328 | { | |
329 | *dst = *src; | |
330 | return 0; | |
331 | } | |
332 | ||
d4311ff1 AT |
333 | void set_task_stack_end_magic(struct task_struct *tsk) |
334 | { | |
335 | unsigned long *stackend; | |
336 | ||
337 | stackend = end_of_stack(tsk); | |
338 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
339 | } | |
340 | ||
725fc629 | 341 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node) |
1da177e4 LT |
342 | { |
343 | struct task_struct *tsk; | |
b235beea | 344 | unsigned long *stack; |
3e26c149 | 345 | int err; |
1da177e4 | 346 | |
725fc629 AK |
347 | if (node == NUMA_NO_NODE) |
348 | node = tsk_fork_get_node(orig); | |
504f52b5 | 349 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
350 | if (!tsk) |
351 | return NULL; | |
352 | ||
b235beea LT |
353 | stack = alloc_thread_stack_node(tsk, node); |
354 | if (!stack) | |
f19b9f74 | 355 | goto free_tsk; |
1da177e4 | 356 | |
fb0a685c | 357 | err = arch_dup_task_struct(tsk, orig); |
164c33c6 | 358 | if (err) |
b235beea | 359 | goto free_stack; |
164c33c6 | 360 | |
b235beea | 361 | tsk->stack = stack; |
dbd95212 KC |
362 | #ifdef CONFIG_SECCOMP |
363 | /* | |
364 | * We must handle setting up seccomp filters once we're under | |
365 | * the sighand lock in case orig has changed between now and | |
366 | * then. Until then, filter must be NULL to avoid messing up | |
367 | * the usage counts on the error path calling free_task. | |
368 | */ | |
369 | tsk->seccomp.filter = NULL; | |
370 | #endif | |
87bec58a AM |
371 | |
372 | setup_thread_stack(tsk, orig); | |
8e7cac79 | 373 | clear_user_return_notifier(tsk); |
f26f9aff | 374 | clear_tsk_need_resched(tsk); |
d4311ff1 | 375 | set_task_stack_end_magic(tsk); |
1da177e4 | 376 | |
0a425405 AV |
377 | #ifdef CONFIG_CC_STACKPROTECTOR |
378 | tsk->stack_canary = get_random_int(); | |
379 | #endif | |
380 | ||
fb0a685c DRO |
381 | /* |
382 | * One for us, one for whoever does the "release_task()" (usually | |
383 | * parent) | |
384 | */ | |
385 | atomic_set(&tsk->usage, 2); | |
6c5c9341 | 386 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 387 | tsk->btrace_seq = 0; |
6c5c9341 | 388 | #endif |
a0aa7f68 | 389 | tsk->splice_pipe = NULL; |
5640f768 | 390 | tsk->task_frag.page = NULL; |
093e5840 | 391 | tsk->wake_q.next = NULL; |
c6a7f572 | 392 | |
b235beea | 393 | account_kernel_stack(stack, 1); |
c6a7f572 | 394 | |
5c9a8750 DV |
395 | kcov_task_init(tsk); |
396 | ||
1da177e4 | 397 | return tsk; |
61c4628b | 398 | |
b235beea LT |
399 | free_stack: |
400 | free_thread_stack(stack); | |
f19b9f74 | 401 | free_tsk: |
61c4628b SS |
402 | free_task_struct(tsk); |
403 | return NULL; | |
1da177e4 LT |
404 | } |
405 | ||
406 | #ifdef CONFIG_MMU | |
a39bc516 | 407 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 408 | { |
297c5eee | 409 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; |
1da177e4 LT |
410 | struct rb_node **rb_link, *rb_parent; |
411 | int retval; | |
412 | unsigned long charge; | |
1da177e4 | 413 | |
32cdba1e | 414 | uprobe_start_dup_mmap(); |
7c051267 MH |
415 | if (down_write_killable(&oldmm->mmap_sem)) { |
416 | retval = -EINTR; | |
417 | goto fail_uprobe_end; | |
418 | } | |
ec8c0446 | 419 | flush_cache_dup_mm(oldmm); |
f8ac4ec9 | 420 | uprobe_dup_mmap(oldmm, mm); |
ad339451 IM |
421 | /* |
422 | * Not linked in yet - no deadlock potential: | |
423 | */ | |
424 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 425 | |
90f31d0e KK |
426 | /* No ordering required: file already has been exposed. */ |
427 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
428 | ||
4f7d4614 | 429 | mm->total_vm = oldmm->total_vm; |
84638335 | 430 | mm->data_vm = oldmm->data_vm; |
4f7d4614 VD |
431 | mm->exec_vm = oldmm->exec_vm; |
432 | mm->stack_vm = oldmm->stack_vm; | |
433 | ||
1da177e4 LT |
434 | rb_link = &mm->mm_rb.rb_node; |
435 | rb_parent = NULL; | |
436 | pprev = &mm->mmap; | |
f8af4da3 | 437 | retval = ksm_fork(mm, oldmm); |
ba76149f AA |
438 | if (retval) |
439 | goto out; | |
440 | retval = khugepaged_fork(mm, oldmm); | |
f8af4da3 HD |
441 | if (retval) |
442 | goto out; | |
1da177e4 | 443 | |
297c5eee | 444 | prev = NULL; |
fd3e42fc | 445 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
446 | struct file *file; |
447 | ||
448 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
84638335 | 449 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt)); |
1da177e4 LT |
450 | continue; |
451 | } | |
452 | charge = 0; | |
453 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
b2412b7f HS |
454 | unsigned long len = vma_pages(mpnt); |
455 | ||
191c5424 | 456 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ |
1da177e4 LT |
457 | goto fail_nomem; |
458 | charge = len; | |
459 | } | |
e94b1766 | 460 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
461 | if (!tmp) |
462 | goto fail_nomem; | |
463 | *tmp = *mpnt; | |
5beb4930 | 464 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
ef0855d3 ON |
465 | retval = vma_dup_policy(mpnt, tmp); |
466 | if (retval) | |
1da177e4 | 467 | goto fail_nomem_policy; |
a247c3a9 | 468 | tmp->vm_mm = mm; |
5beb4930 RR |
469 | if (anon_vma_fork(tmp, mpnt)) |
470 | goto fail_nomem_anon_vma_fork; | |
de60f5f1 EM |
471 | tmp->vm_flags &= |
472 | ~(VM_LOCKED|VM_LOCKONFAULT|VM_UFFD_MISSING|VM_UFFD_WP); | |
297c5eee | 473 | tmp->vm_next = tmp->vm_prev = NULL; |
745f234b | 474 | tmp->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX; |
1da177e4 LT |
475 | file = tmp->vm_file; |
476 | if (file) { | |
496ad9aa | 477 | struct inode *inode = file_inode(file); |
b88ed205 HD |
478 | struct address_space *mapping = file->f_mapping; |
479 | ||
1da177e4 LT |
480 | get_file(file); |
481 | if (tmp->vm_flags & VM_DENYWRITE) | |
482 | atomic_dec(&inode->i_writecount); | |
83cde9e8 | 483 | i_mmap_lock_write(mapping); |
b88ed205 | 484 | if (tmp->vm_flags & VM_SHARED) |
4bb5f5d9 | 485 | atomic_inc(&mapping->i_mmap_writable); |
b88ed205 HD |
486 | flush_dcache_mmap_lock(mapping); |
487 | /* insert tmp into the share list, just after mpnt */ | |
27ba0644 KS |
488 | vma_interval_tree_insert_after(tmp, mpnt, |
489 | &mapping->i_mmap); | |
b88ed205 | 490 | flush_dcache_mmap_unlock(mapping); |
83cde9e8 | 491 | i_mmap_unlock_write(mapping); |
1da177e4 LT |
492 | } |
493 | ||
a1e78772 MG |
494 | /* |
495 | * Clear hugetlb-related page reserves for children. This only | |
496 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
497 | * are not guaranteed to succeed, even if read-only | |
498 | */ | |
499 | if (is_vm_hugetlb_page(tmp)) | |
500 | reset_vma_resv_huge_pages(tmp); | |
501 | ||
1da177e4 | 502 | /* |
7ee78232 | 503 | * Link in the new vma and copy the page table entries. |
1da177e4 | 504 | */ |
1da177e4 LT |
505 | *pprev = tmp; |
506 | pprev = &tmp->vm_next; | |
297c5eee LT |
507 | tmp->vm_prev = prev; |
508 | prev = tmp; | |
1da177e4 LT |
509 | |
510 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
511 | rb_link = &tmp->vm_rb.rb_right; | |
512 | rb_parent = &tmp->vm_rb; | |
513 | ||
514 | mm->map_count++; | |
0b0db14c | 515 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
516 | |
517 | if (tmp->vm_ops && tmp->vm_ops->open) | |
518 | tmp->vm_ops->open(tmp); | |
519 | ||
520 | if (retval) | |
521 | goto out; | |
522 | } | |
d6dd61c8 JF |
523 | /* a new mm has just been created */ |
524 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 525 | retval = 0; |
1da177e4 | 526 | out: |
7ee78232 | 527 | up_write(&mm->mmap_sem); |
fd3e42fc | 528 | flush_tlb_mm(oldmm); |
1da177e4 | 529 | up_write(&oldmm->mmap_sem); |
7c051267 | 530 | fail_uprobe_end: |
32cdba1e | 531 | uprobe_end_dup_mmap(); |
1da177e4 | 532 | return retval; |
5beb4930 | 533 | fail_nomem_anon_vma_fork: |
ef0855d3 | 534 | mpol_put(vma_policy(tmp)); |
1da177e4 LT |
535 | fail_nomem_policy: |
536 | kmem_cache_free(vm_area_cachep, tmp); | |
537 | fail_nomem: | |
538 | retval = -ENOMEM; | |
539 | vm_unacct_memory(charge); | |
540 | goto out; | |
541 | } | |
542 | ||
fb0a685c | 543 | static inline int mm_alloc_pgd(struct mm_struct *mm) |
1da177e4 LT |
544 | { |
545 | mm->pgd = pgd_alloc(mm); | |
546 | if (unlikely(!mm->pgd)) | |
547 | return -ENOMEM; | |
548 | return 0; | |
549 | } | |
550 | ||
fb0a685c | 551 | static inline void mm_free_pgd(struct mm_struct *mm) |
1da177e4 | 552 | { |
5e541973 | 553 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
554 | } |
555 | #else | |
90f31d0e KK |
556 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
557 | { | |
558 | down_write(&oldmm->mmap_sem); | |
559 | RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); | |
560 | up_write(&oldmm->mmap_sem); | |
561 | return 0; | |
562 | } | |
1da177e4 LT |
563 | #define mm_alloc_pgd(mm) (0) |
564 | #define mm_free_pgd(mm) | |
565 | #endif /* CONFIG_MMU */ | |
566 | ||
23ff4440 | 567 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 568 | |
e94b1766 | 569 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
570 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
571 | ||
4cb0e11b HK |
572 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
573 | ||
574 | static int __init coredump_filter_setup(char *s) | |
575 | { | |
576 | default_dump_filter = | |
577 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
578 | MMF_DUMP_FILTER_MASK; | |
579 | return 1; | |
580 | } | |
581 | ||
582 | __setup("coredump_filter=", coredump_filter_setup); | |
583 | ||
1da177e4 LT |
584 | #include <linux/init_task.h> |
585 | ||
858f0993 AD |
586 | static void mm_init_aio(struct mm_struct *mm) |
587 | { | |
588 | #ifdef CONFIG_AIO | |
589 | spin_lock_init(&mm->ioctx_lock); | |
db446a08 | 590 | mm->ioctx_table = NULL; |
858f0993 AD |
591 | #endif |
592 | } | |
593 | ||
33144e84 VD |
594 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
595 | { | |
596 | #ifdef CONFIG_MEMCG | |
597 | mm->owner = p; | |
598 | #endif | |
599 | } | |
600 | ||
fb0a685c | 601 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) |
1da177e4 | 602 | { |
41f727fd VD |
603 | mm->mmap = NULL; |
604 | mm->mm_rb = RB_ROOT; | |
605 | mm->vmacache_seqnum = 0; | |
1da177e4 LT |
606 | atomic_set(&mm->mm_users, 1); |
607 | atomic_set(&mm->mm_count, 1); | |
608 | init_rwsem(&mm->mmap_sem); | |
609 | INIT_LIST_HEAD(&mm->mmlist); | |
999d9fc1 | 610 | mm->core_state = NULL; |
e1f56c89 | 611 | atomic_long_set(&mm->nr_ptes, 0); |
2d2f5119 | 612 | mm_nr_pmds_init(mm); |
41f727fd VD |
613 | mm->map_count = 0; |
614 | mm->locked_vm = 0; | |
ce65cefa | 615 | mm->pinned_vm = 0; |
d559db08 | 616 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 617 | spin_lock_init(&mm->page_table_lock); |
41f727fd | 618 | mm_init_cpumask(mm); |
858f0993 | 619 | mm_init_aio(mm); |
cf475ad2 | 620 | mm_init_owner(mm, p); |
41f727fd | 621 | mmu_notifier_mm_init(mm); |
20841405 | 622 | clear_tlb_flush_pending(mm); |
41f727fd VD |
623 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
624 | mm->pmd_huge_pte = NULL; | |
625 | #endif | |
1da177e4 | 626 | |
a0715cc2 AT |
627 | if (current->mm) { |
628 | mm->flags = current->mm->flags & MMF_INIT_MASK; | |
629 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; | |
630 | } else { | |
631 | mm->flags = default_dump_filter; | |
1da177e4 | 632 | mm->def_flags = 0; |
a0715cc2 AT |
633 | } |
634 | ||
41f727fd VD |
635 | if (mm_alloc_pgd(mm)) |
636 | goto fail_nopgd; | |
637 | ||
638 | if (init_new_context(p, mm)) | |
639 | goto fail_nocontext; | |
78fb7466 | 640 | |
41f727fd VD |
641 | return mm; |
642 | ||
643 | fail_nocontext: | |
644 | mm_free_pgd(mm); | |
645 | fail_nopgd: | |
1da177e4 LT |
646 | free_mm(mm); |
647 | return NULL; | |
648 | } | |
649 | ||
c3f0327f KK |
650 | static void check_mm(struct mm_struct *mm) |
651 | { | |
652 | int i; | |
653 | ||
654 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
655 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
656 | ||
657 | if (unlikely(x)) | |
658 | printk(KERN_ALERT "BUG: Bad rss-counter state " | |
659 | "mm:%p idx:%d val:%ld\n", mm, i, x); | |
660 | } | |
b30fe6c7 KS |
661 | |
662 | if (atomic_long_read(&mm->nr_ptes)) | |
663 | pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld\n", | |
664 | atomic_long_read(&mm->nr_ptes)); | |
665 | if (mm_nr_pmds(mm)) | |
666 | pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld\n", | |
667 | mm_nr_pmds(mm)); | |
668 | ||
e009bb30 | 669 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS |
96dad67f | 670 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm); |
c3f0327f KK |
671 | #endif |
672 | } | |
673 | ||
1da177e4 LT |
674 | /* |
675 | * Allocate and initialize an mm_struct. | |
676 | */ | |
fb0a685c | 677 | struct mm_struct *mm_alloc(void) |
1da177e4 | 678 | { |
fb0a685c | 679 | struct mm_struct *mm; |
1da177e4 LT |
680 | |
681 | mm = allocate_mm(); | |
de03c72c KM |
682 | if (!mm) |
683 | return NULL; | |
684 | ||
685 | memset(mm, 0, sizeof(*mm)); | |
6345d24d | 686 | return mm_init(mm, current); |
1da177e4 LT |
687 | } |
688 | ||
689 | /* | |
690 | * Called when the last reference to the mm | |
691 | * is dropped: either by a lazy thread or by | |
692 | * mmput. Free the page directory and the mm. | |
693 | */ | |
7ad5b3a5 | 694 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
695 | { |
696 | BUG_ON(mm == &init_mm); | |
697 | mm_free_pgd(mm); | |
698 | destroy_context(mm); | |
cddb8a5c | 699 | mmu_notifier_mm_destroy(mm); |
c3f0327f | 700 | check_mm(mm); |
1da177e4 LT |
701 | free_mm(mm); |
702 | } | |
6d4e4c4f | 703 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 | 704 | |
ec8d7c14 MH |
705 | static inline void __mmput(struct mm_struct *mm) |
706 | { | |
707 | VM_BUG_ON(atomic_read(&mm->mm_users)); | |
708 | ||
709 | uprobe_clear_state(mm); | |
710 | exit_aio(mm); | |
711 | ksm_exit(mm); | |
712 | khugepaged_exit(mm); /* must run before exit_mmap */ | |
713 | exit_mmap(mm); | |
714 | set_mm_exe_file(mm, NULL); | |
715 | if (!list_empty(&mm->mmlist)) { | |
716 | spin_lock(&mmlist_lock); | |
717 | list_del(&mm->mmlist); | |
718 | spin_unlock(&mmlist_lock); | |
719 | } | |
720 | if (mm->binfmt) | |
721 | module_put(mm->binfmt->module); | |
722 | mmdrop(mm); | |
723 | } | |
724 | ||
1da177e4 LT |
725 | /* |
726 | * Decrement the use count and release all resources for an mm. | |
727 | */ | |
728 | void mmput(struct mm_struct *mm) | |
729 | { | |
0ae26f1b AM |
730 | might_sleep(); |
731 | ||
ec8d7c14 MH |
732 | if (atomic_dec_and_test(&mm->mm_users)) |
733 | __mmput(mm); | |
734 | } | |
735 | EXPORT_SYMBOL_GPL(mmput); | |
736 | ||
7ef949d7 | 737 | #ifdef CONFIG_MMU |
ec8d7c14 MH |
738 | static void mmput_async_fn(struct work_struct *work) |
739 | { | |
740 | struct mm_struct *mm = container_of(work, struct mm_struct, async_put_work); | |
741 | __mmput(mm); | |
742 | } | |
743 | ||
744 | void mmput_async(struct mm_struct *mm) | |
745 | { | |
1da177e4 | 746 | if (atomic_dec_and_test(&mm->mm_users)) { |
ec8d7c14 MH |
747 | INIT_WORK(&mm->async_put_work, mmput_async_fn); |
748 | schedule_work(&mm->async_put_work); | |
1da177e4 LT |
749 | } |
750 | } | |
7ef949d7 | 751 | #endif |
1da177e4 | 752 | |
90f31d0e KK |
753 | /** |
754 | * set_mm_exe_file - change a reference to the mm's executable file | |
755 | * | |
756 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe). | |
757 | * | |
6e399cd1 DB |
758 | * Main users are mmput() and sys_execve(). Callers prevent concurrent |
759 | * invocations: in mmput() nobody alive left, in execve task is single | |
760 | * threaded. sys_prctl(PR_SET_MM_MAP/EXE_FILE) also needs to set the | |
761 | * mm->exe_file, but does so without using set_mm_exe_file() in order | |
762 | * to do avoid the need for any locks. | |
90f31d0e | 763 | */ |
38646013 JS |
764 | void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) |
765 | { | |
6e399cd1 DB |
766 | struct file *old_exe_file; |
767 | ||
768 | /* | |
769 | * It is safe to dereference the exe_file without RCU as | |
770 | * this function is only called if nobody else can access | |
771 | * this mm -- see comment above for justification. | |
772 | */ | |
773 | old_exe_file = rcu_dereference_raw(mm->exe_file); | |
90f31d0e | 774 | |
38646013 JS |
775 | if (new_exe_file) |
776 | get_file(new_exe_file); | |
90f31d0e KK |
777 | rcu_assign_pointer(mm->exe_file, new_exe_file); |
778 | if (old_exe_file) | |
779 | fput(old_exe_file); | |
38646013 JS |
780 | } |
781 | ||
90f31d0e KK |
782 | /** |
783 | * get_mm_exe_file - acquire a reference to the mm's executable file | |
784 | * | |
785 | * Returns %NULL if mm has no associated executable file. | |
786 | * User must release file via fput(). | |
787 | */ | |
38646013 JS |
788 | struct file *get_mm_exe_file(struct mm_struct *mm) |
789 | { | |
790 | struct file *exe_file; | |
791 | ||
90f31d0e KK |
792 | rcu_read_lock(); |
793 | exe_file = rcu_dereference(mm->exe_file); | |
794 | if (exe_file && !get_file_rcu(exe_file)) | |
795 | exe_file = NULL; | |
796 | rcu_read_unlock(); | |
38646013 JS |
797 | return exe_file; |
798 | } | |
11163348 | 799 | EXPORT_SYMBOL(get_mm_exe_file); |
38646013 | 800 | |
cd81a917 MG |
801 | /** |
802 | * get_task_exe_file - acquire a reference to the task's executable file | |
803 | * | |
804 | * Returns %NULL if task's mm (if any) has no associated executable file or | |
805 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm). | |
806 | * User must release file via fput(). | |
807 | */ | |
808 | struct file *get_task_exe_file(struct task_struct *task) | |
809 | { | |
810 | struct file *exe_file = NULL; | |
811 | struct mm_struct *mm; | |
812 | ||
813 | task_lock(task); | |
814 | mm = task->mm; | |
815 | if (mm) { | |
816 | if (!(task->flags & PF_KTHREAD)) | |
817 | exe_file = get_mm_exe_file(mm); | |
818 | } | |
819 | task_unlock(task); | |
820 | return exe_file; | |
821 | } | |
822 | EXPORT_SYMBOL(get_task_exe_file); | |
38646013 | 823 | |
1da177e4 LT |
824 | /** |
825 | * get_task_mm - acquire a reference to the task's mm | |
826 | * | |
246bb0b1 | 827 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
828 | * this kernel workthread has transiently adopted a user mm with use_mm, |
829 | * to do its AIO) is not set and if so returns a reference to it, after | |
830 | * bumping up the use count. User must release the mm via mmput() | |
831 | * after use. Typically used by /proc and ptrace. | |
832 | */ | |
833 | struct mm_struct *get_task_mm(struct task_struct *task) | |
834 | { | |
835 | struct mm_struct *mm; | |
836 | ||
837 | task_lock(task); | |
838 | mm = task->mm; | |
839 | if (mm) { | |
246bb0b1 | 840 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
841 | mm = NULL; |
842 | else | |
843 | atomic_inc(&mm->mm_users); | |
844 | } | |
845 | task_unlock(task); | |
846 | return mm; | |
847 | } | |
848 | EXPORT_SYMBOL_GPL(get_task_mm); | |
849 | ||
8cdb878d CY |
850 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
851 | { | |
852 | struct mm_struct *mm; | |
853 | int err; | |
854 | ||
855 | err = mutex_lock_killable(&task->signal->cred_guard_mutex); | |
856 | if (err) | |
857 | return ERR_PTR(err); | |
858 | ||
859 | mm = get_task_mm(task); | |
860 | if (mm && mm != current->mm && | |
861 | !ptrace_may_access(task, mode)) { | |
862 | mmput(mm); | |
863 | mm = ERR_PTR(-EACCES); | |
864 | } | |
865 | mutex_unlock(&task->signal->cred_guard_mutex); | |
866 | ||
867 | return mm; | |
868 | } | |
869 | ||
57b59c4a | 870 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 871 | { |
d68b46fe | 872 | struct completion *vfork; |
c415c3b4 | 873 | |
d68b46fe ON |
874 | task_lock(tsk); |
875 | vfork = tsk->vfork_done; | |
876 | if (likely(vfork)) { | |
877 | tsk->vfork_done = NULL; | |
878 | complete(vfork); | |
879 | } | |
880 | task_unlock(tsk); | |
881 | } | |
882 | ||
883 | static int wait_for_vfork_done(struct task_struct *child, | |
884 | struct completion *vfork) | |
885 | { | |
886 | int killed; | |
887 | ||
888 | freezer_do_not_count(); | |
889 | killed = wait_for_completion_killable(vfork); | |
890 | freezer_count(); | |
891 | ||
892 | if (killed) { | |
893 | task_lock(child); | |
894 | child->vfork_done = NULL; | |
895 | task_unlock(child); | |
896 | } | |
897 | ||
898 | put_task_struct(child); | |
899 | return killed; | |
c415c3b4 ON |
900 | } |
901 | ||
1da177e4 LT |
902 | /* Please note the differences between mmput and mm_release. |
903 | * mmput is called whenever we stop holding onto a mm_struct, | |
904 | * error success whatever. | |
905 | * | |
906 | * mm_release is called after a mm_struct has been removed | |
907 | * from the current process. | |
908 | * | |
909 | * This difference is important for error handling, when we | |
910 | * only half set up a mm_struct for a new process and need to restore | |
911 | * the old one. Because we mmput the new mm_struct before | |
912 | * restoring the old one. . . | |
913 | * Eric Biederman 10 January 1998 | |
914 | */ | |
915 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
916 | { | |
8141c7f3 LT |
917 | /* Get rid of any futexes when releasing the mm */ |
918 | #ifdef CONFIG_FUTEX | |
fc6b177d | 919 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 920 | exit_robust_list(tsk); |
fc6b177d PZ |
921 | tsk->robust_list = NULL; |
922 | } | |
8141c7f3 | 923 | #ifdef CONFIG_COMPAT |
fc6b177d | 924 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 925 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
926 | tsk->compat_robust_list = NULL; |
927 | } | |
8141c7f3 | 928 | #endif |
322a2c10 TG |
929 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
930 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
931 | #endif |
932 | ||
0326f5a9 SD |
933 | uprobe_free_utask(tsk); |
934 | ||
1da177e4 LT |
935 | /* Get rid of any cached register state */ |
936 | deactivate_mm(tsk, mm); | |
937 | ||
fec1d011 | 938 | /* |
735f2770 MH |
939 | * Signal userspace if we're not exiting with a core dump |
940 | * because we want to leave the value intact for debugging | |
941 | * purposes. | |
fec1d011 | 942 | */ |
9c8a8228 | 943 | if (tsk->clear_child_tid) { |
735f2770 | 944 | if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) && |
9c8a8228 ED |
945 | atomic_read(&mm->mm_users) > 1) { |
946 | /* | |
947 | * We don't check the error code - if userspace has | |
948 | * not set up a proper pointer then tough luck. | |
949 | */ | |
950 | put_user(0, tsk->clear_child_tid); | |
951 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
952 | 1, NULL, NULL, 0); | |
953 | } | |
1da177e4 | 954 | tsk->clear_child_tid = NULL; |
1da177e4 | 955 | } |
f7505d64 KK |
956 | |
957 | /* | |
958 | * All done, finally we can wake up parent and return this mm to him. | |
959 | * Also kthread_stop() uses this completion for synchronization. | |
960 | */ | |
961 | if (tsk->vfork_done) | |
962 | complete_vfork_done(tsk); | |
1da177e4 LT |
963 | } |
964 | ||
a0a7ec30 JD |
965 | /* |
966 | * Allocate a new mm structure and copy contents from the | |
967 | * mm structure of the passed in task structure. | |
968 | */ | |
ff252c1f | 969 | static struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
970 | { |
971 | struct mm_struct *mm, *oldmm = current->mm; | |
972 | int err; | |
973 | ||
a0a7ec30 JD |
974 | mm = allocate_mm(); |
975 | if (!mm) | |
976 | goto fail_nomem; | |
977 | ||
978 | memcpy(mm, oldmm, sizeof(*mm)); | |
979 | ||
78fb7466 | 980 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
981 | goto fail_nomem; |
982 | ||
a0a7ec30 JD |
983 | err = dup_mmap(mm, oldmm); |
984 | if (err) | |
985 | goto free_pt; | |
986 | ||
987 | mm->hiwater_rss = get_mm_rss(mm); | |
988 | mm->hiwater_vm = mm->total_vm; | |
989 | ||
801460d0 HS |
990 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
991 | goto free_pt; | |
992 | ||
a0a7ec30 JD |
993 | return mm; |
994 | ||
995 | free_pt: | |
801460d0 HS |
996 | /* don't put binfmt in mmput, we haven't got module yet */ |
997 | mm->binfmt = NULL; | |
a0a7ec30 JD |
998 | mmput(mm); |
999 | ||
1000 | fail_nomem: | |
1001 | return NULL; | |
a0a7ec30 JD |
1002 | } |
1003 | ||
fb0a685c | 1004 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1005 | { |
fb0a685c | 1006 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
1007 | int retval; |
1008 | ||
1009 | tsk->min_flt = tsk->maj_flt = 0; | |
1010 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
1011 | #ifdef CONFIG_DETECT_HUNG_TASK |
1012 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
1013 | #endif | |
1da177e4 LT |
1014 | |
1015 | tsk->mm = NULL; | |
1016 | tsk->active_mm = NULL; | |
1017 | ||
1018 | /* | |
1019 | * Are we cloning a kernel thread? | |
1020 | * | |
1021 | * We need to steal a active VM for that.. | |
1022 | */ | |
1023 | oldmm = current->mm; | |
1024 | if (!oldmm) | |
1025 | return 0; | |
1026 | ||
615d6e87 DB |
1027 | /* initialize the new vmacache entries */ |
1028 | vmacache_flush(tsk); | |
1029 | ||
1da177e4 LT |
1030 | if (clone_flags & CLONE_VM) { |
1031 | atomic_inc(&oldmm->mm_users); | |
1032 | mm = oldmm; | |
1da177e4 LT |
1033 | goto good_mm; |
1034 | } | |
1035 | ||
1036 | retval = -ENOMEM; | |
a0a7ec30 | 1037 | mm = dup_mm(tsk); |
1da177e4 LT |
1038 | if (!mm) |
1039 | goto fail_nomem; | |
1040 | ||
1da177e4 LT |
1041 | good_mm: |
1042 | tsk->mm = mm; | |
1043 | tsk->active_mm = mm; | |
1044 | return 0; | |
1045 | ||
1da177e4 LT |
1046 | fail_nomem: |
1047 | return retval; | |
1da177e4 LT |
1048 | } |
1049 | ||
a39bc516 | 1050 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 1051 | { |
498052bb | 1052 | struct fs_struct *fs = current->fs; |
1da177e4 | 1053 | if (clone_flags & CLONE_FS) { |
498052bb | 1054 | /* tsk->fs is already what we want */ |
2a4419b5 | 1055 | spin_lock(&fs->lock); |
498052bb | 1056 | if (fs->in_exec) { |
2a4419b5 | 1057 | spin_unlock(&fs->lock); |
498052bb AV |
1058 | return -EAGAIN; |
1059 | } | |
1060 | fs->users++; | |
2a4419b5 | 1061 | spin_unlock(&fs->lock); |
1da177e4 LT |
1062 | return 0; |
1063 | } | |
498052bb | 1064 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
1065 | if (!tsk->fs) |
1066 | return -ENOMEM; | |
1067 | return 0; | |
1068 | } | |
1069 | ||
fb0a685c | 1070 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
1071 | { |
1072 | struct files_struct *oldf, *newf; | |
1073 | int error = 0; | |
1074 | ||
1075 | /* | |
1076 | * A background process may not have any files ... | |
1077 | */ | |
1078 | oldf = current->files; | |
1079 | if (!oldf) | |
1080 | goto out; | |
1081 | ||
1082 | if (clone_flags & CLONE_FILES) { | |
1083 | atomic_inc(&oldf->count); | |
1084 | goto out; | |
1085 | } | |
1086 | ||
a016f338 JD |
1087 | newf = dup_fd(oldf, &error); |
1088 | if (!newf) | |
1089 | goto out; | |
1090 | ||
1091 | tsk->files = newf; | |
1092 | error = 0; | |
1093 | out: | |
1094 | return error; | |
1095 | } | |
1096 | ||
fadad878 | 1097 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
1098 | { |
1099 | #ifdef CONFIG_BLOCK | |
1100 | struct io_context *ioc = current->io_context; | |
6e736be7 | 1101 | struct io_context *new_ioc; |
fd0928df JA |
1102 | |
1103 | if (!ioc) | |
1104 | return 0; | |
fadad878 JA |
1105 | /* |
1106 | * Share io context with parent, if CLONE_IO is set | |
1107 | */ | |
1108 | if (clone_flags & CLONE_IO) { | |
3d48749d TH |
1109 | ioc_task_link(ioc); |
1110 | tsk->io_context = ioc; | |
fadad878 | 1111 | } else if (ioprio_valid(ioc->ioprio)) { |
6e736be7 TH |
1112 | new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE); |
1113 | if (unlikely(!new_ioc)) | |
fd0928df JA |
1114 | return -ENOMEM; |
1115 | ||
6e736be7 | 1116 | new_ioc->ioprio = ioc->ioprio; |
11a3122f | 1117 | put_io_context(new_ioc); |
fd0928df JA |
1118 | } |
1119 | #endif | |
1120 | return 0; | |
1121 | } | |
1122 | ||
a39bc516 | 1123 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1124 | { |
1125 | struct sighand_struct *sig; | |
1126 | ||
60348802 | 1127 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
1128 | atomic_inc(¤t->sighand->count); |
1129 | return 0; | |
1130 | } | |
1131 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 1132 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
1133 | if (!sig) |
1134 | return -ENOMEM; | |
9d7fb042 | 1135 | |
1da177e4 LT |
1136 | atomic_set(&sig->count, 1); |
1137 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
1138 | return 0; | |
1139 | } | |
1140 | ||
a7e5328a | 1141 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1142 | { |
d80e731e ON |
1143 | if (atomic_dec_and_test(&sighand->count)) { |
1144 | signalfd_cleanup(sighand); | |
392809b2 ON |
1145 | /* |
1146 | * sighand_cachep is SLAB_DESTROY_BY_RCU so we can free it | |
1147 | * without an RCU grace period, see __lock_task_sighand(). | |
1148 | */ | |
c81addc9 | 1149 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1150 | } |
c81addc9 ON |
1151 | } |
1152 | ||
f06febc9 FM |
1153 | /* |
1154 | * Initialize POSIX timer handling for a thread group. | |
1155 | */ | |
1156 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1157 | { | |
78d7d407 JS |
1158 | unsigned long cpu_limit; |
1159 | ||
316c1608 | 1160 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
78d7d407 JS |
1161 | if (cpu_limit != RLIM_INFINITY) { |
1162 | sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit); | |
d5c373eb | 1163 | sig->cputimer.running = true; |
6279a751 ON |
1164 | } |
1165 | ||
f06febc9 FM |
1166 | /* The timer lists. */ |
1167 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
1168 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
1169 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
1170 | } | |
1171 | ||
a39bc516 | 1172 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1173 | { |
1174 | struct signal_struct *sig; | |
1da177e4 | 1175 | |
4ab6c083 | 1176 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1177 | return 0; |
490dea45 | 1178 | |
a56704ef | 1179 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1180 | tsk->signal = sig; |
1181 | if (!sig) | |
1182 | return -ENOMEM; | |
1183 | ||
b3ac022c | 1184 | sig->nr_threads = 1; |
1da177e4 | 1185 | atomic_set(&sig->live, 1); |
b3ac022c | 1186 | atomic_set(&sig->sigcnt, 1); |
0c740d0a ON |
1187 | |
1188 | /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */ | |
1189 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node); | |
1190 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head); | |
1191 | ||
1da177e4 | 1192 | init_waitqueue_head(&sig->wait_chldexit); |
db51aecc | 1193 | sig->curr_target = tsk; |
1da177e4 LT |
1194 | init_sigpending(&sig->shared_pending); |
1195 | INIT_LIST_HEAD(&sig->posix_timers); | |
e78c3496 | 1196 | seqlock_init(&sig->stats_lock); |
9d7fb042 | 1197 | prev_cputime_init(&sig->prev_cputime); |
1da177e4 | 1198 | |
c9cb2e3d | 1199 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1200 | sig->real_timer.function = it_real_fn; |
1da177e4 | 1201 | |
1da177e4 LT |
1202 | task_lock(current->group_leader); |
1203 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1204 | task_unlock(current->group_leader); | |
1205 | ||
6279a751 ON |
1206 | posix_cpu_timers_init_group(sig); |
1207 | ||
522ed776 | 1208 | tty_audit_fork(sig); |
5091faa4 | 1209 | sched_autogroup_fork(sig); |
522ed776 | 1210 | |
a63d83f4 | 1211 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1212 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1213 | |
ebec18a6 LP |
1214 | sig->has_child_subreaper = current->signal->has_child_subreaper || |
1215 | current->signal->is_child_subreaper; | |
1216 | ||
9b1bf12d KM |
1217 | mutex_init(&sig->cred_guard_mutex); |
1218 | ||
1da177e4 LT |
1219 | return 0; |
1220 | } | |
1221 | ||
dbd95212 KC |
1222 | static void copy_seccomp(struct task_struct *p) |
1223 | { | |
1224 | #ifdef CONFIG_SECCOMP | |
1225 | /* | |
1226 | * Must be called with sighand->lock held, which is common to | |
1227 | * all threads in the group. Holding cred_guard_mutex is not | |
1228 | * needed because this new task is not yet running and cannot | |
1229 | * be racing exec. | |
1230 | */ | |
69f6a34b | 1231 | assert_spin_locked(¤t->sighand->siglock); |
dbd95212 KC |
1232 | |
1233 | /* Ref-count the new filter user, and assign it. */ | |
1234 | get_seccomp_filter(current); | |
1235 | p->seccomp = current->seccomp; | |
1236 | ||
1237 | /* | |
1238 | * Explicitly enable no_new_privs here in case it got set | |
1239 | * between the task_struct being duplicated and holding the | |
1240 | * sighand lock. The seccomp state and nnp must be in sync. | |
1241 | */ | |
1242 | if (task_no_new_privs(current)) | |
1243 | task_set_no_new_privs(p); | |
1244 | ||
1245 | /* | |
1246 | * If the parent gained a seccomp mode after copying thread | |
1247 | * flags and between before we held the sighand lock, we have | |
1248 | * to manually enable the seccomp thread flag here. | |
1249 | */ | |
1250 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED) | |
1251 | set_tsk_thread_flag(p, TIF_SECCOMP); | |
1252 | #endif | |
1253 | } | |
1254 | ||
17da2bd9 | 1255 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1256 | { |
1257 | current->clear_child_tid = tidptr; | |
1258 | ||
b488893a | 1259 | return task_pid_vnr(current); |
1da177e4 LT |
1260 | } |
1261 | ||
a39bc516 | 1262 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1263 | { |
1d615482 | 1264 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1265 | #ifdef CONFIG_RT_MUTEXES |
fb00aca4 PZ |
1266 | p->pi_waiters = RB_ROOT; |
1267 | p->pi_waiters_leftmost = NULL; | |
23f78d4a | 1268 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1269 | #endif |
1270 | } | |
1271 | ||
f06febc9 FM |
1272 | /* |
1273 | * Initialize POSIX timer handling for a single task. | |
1274 | */ | |
1275 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
1276 | { | |
64861634 MS |
1277 | tsk->cputime_expires.prof_exp = 0; |
1278 | tsk->cputime_expires.virt_exp = 0; | |
f06febc9 FM |
1279 | tsk->cputime_expires.sched_exp = 0; |
1280 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
1281 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
1282 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
1283 | } | |
1284 | ||
81907739 ON |
1285 | static inline void |
1286 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid) | |
1287 | { | |
1288 | task->pids[type].pid = pid; | |
1289 | } | |
1290 | ||
1da177e4 LT |
1291 | /* |
1292 | * This creates a new process as a copy of the old one, | |
1293 | * but does not actually start it yet. | |
1294 | * | |
1295 | * It copies the registers, and all the appropriate | |
1296 | * parts of the process environment (as per the clone | |
1297 | * flags). The actual kick-off is left to the caller. | |
1298 | */ | |
36c8b586 IM |
1299 | static struct task_struct *copy_process(unsigned long clone_flags, |
1300 | unsigned long stack_start, | |
36c8b586 | 1301 | unsigned long stack_size, |
36c8b586 | 1302 | int __user *child_tidptr, |
09a05394 | 1303 | struct pid *pid, |
3033f14a | 1304 | int trace, |
725fc629 AK |
1305 | unsigned long tls, |
1306 | int node) | |
1da177e4 LT |
1307 | { |
1308 | int retval; | |
a24efe62 | 1309 | struct task_struct *p; |
1da177e4 LT |
1310 | |
1311 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
1312 | return ERR_PTR(-EINVAL); | |
1313 | ||
e66eded8 EB |
1314 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) |
1315 | return ERR_PTR(-EINVAL); | |
1316 | ||
1da177e4 LT |
1317 | /* |
1318 | * Thread groups must share signals as well, and detached threads | |
1319 | * can only be started up within the thread group. | |
1320 | */ | |
1321 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1322 | return ERR_PTR(-EINVAL); | |
1323 | ||
1324 | /* | |
1325 | * Shared signal handlers imply shared VM. By way of the above, | |
1326 | * thread groups also imply shared VM. Blocking this case allows | |
1327 | * for various simplifications in other code. | |
1328 | */ | |
1329 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1330 | return ERR_PTR(-EINVAL); | |
1331 | ||
123be07b SB |
1332 | /* |
1333 | * Siblings of global init remain as zombies on exit since they are | |
1334 | * not reaped by their parent (swapper). To solve this and to avoid | |
1335 | * multi-rooted process trees, prevent global and container-inits | |
1336 | * from creating siblings. | |
1337 | */ | |
1338 | if ((clone_flags & CLONE_PARENT) && | |
1339 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1340 | return ERR_PTR(-EINVAL); | |
1341 | ||
8382fcac | 1342 | /* |
40a0d32d | 1343 | * If the new process will be in a different pid or user namespace |
faf00da5 | 1344 | * do not allow it to share a thread group with the forking task. |
8382fcac | 1345 | */ |
faf00da5 | 1346 | if (clone_flags & CLONE_THREAD) { |
40a0d32d ON |
1347 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || |
1348 | (task_active_pid_ns(current) != | |
1349 | current->nsproxy->pid_ns_for_children)) | |
1350 | return ERR_PTR(-EINVAL); | |
1351 | } | |
8382fcac | 1352 | |
1da177e4 LT |
1353 | retval = security_task_create(clone_flags); |
1354 | if (retval) | |
1355 | goto fork_out; | |
1356 | ||
1357 | retval = -ENOMEM; | |
725fc629 | 1358 | p = dup_task_struct(current, node); |
1da177e4 LT |
1359 | if (!p) |
1360 | goto fork_out; | |
1361 | ||
f7e8b616 SR |
1362 | ftrace_graph_init_task(p); |
1363 | ||
bea493a0 PZ |
1364 | rt_mutex_init_task(p); |
1365 | ||
d12c1a37 | 1366 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1367 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1368 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1369 | #endif | |
1da177e4 | 1370 | retval = -EAGAIN; |
3b11a1de | 1371 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1372 | task_rlimit(p, RLIMIT_NPROC)) { |
b57922b6 EP |
1373 | if (p->real_cred->user != INIT_USER && |
1374 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
1375 | goto bad_fork_free; |
1376 | } | |
72fa5997 | 1377 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 1378 | |
f1752eec DH |
1379 | retval = copy_creds(p, clone_flags); |
1380 | if (retval < 0) | |
1381 | goto bad_fork_free; | |
1da177e4 LT |
1382 | |
1383 | /* | |
1384 | * If multiple threads are within copy_process(), then this check | |
1385 | * triggers too late. This doesn't hurt, the check is only there | |
1386 | * to stop root fork bombs. | |
1387 | */ | |
04ec93fe | 1388 | retval = -EAGAIN; |
1da177e4 LT |
1389 | if (nr_threads >= max_threads) |
1390 | goto bad_fork_cleanup_count; | |
1391 | ||
ca74e92b | 1392 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
514ddb44 DR |
1393 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER); |
1394 | p->flags |= PF_FORKNOEXEC; | |
1da177e4 LT |
1395 | INIT_LIST_HEAD(&p->children); |
1396 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1397 | rcu_copy_process(p); |
1da177e4 LT |
1398 | p->vfork_done = NULL; |
1399 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1400 | |
1da177e4 LT |
1401 | init_sigpending(&p->pending); |
1402 | ||
64861634 MS |
1403 | p->utime = p->stime = p->gtime = 0; |
1404 | p->utimescaled = p->stimescaled = 0; | |
9d7fb042 PZ |
1405 | prev_cputime_init(&p->prev_cputime); |
1406 | ||
6a61671b | 1407 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
b7ce2277 | 1408 | seqcount_init(&p->vtime_seqcount); |
6a61671b | 1409 | p->vtime_snap = 0; |
7098c1ea | 1410 | p->vtime_snap_whence = VTIME_INACTIVE; |
6a61671b FW |
1411 | #endif |
1412 | ||
a3a2e76c KH |
1413 | #if defined(SPLIT_RSS_COUNTING) |
1414 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1415 | #endif | |
172ba844 | 1416 | |
6976675d AV |
1417 | p->default_timer_slack_ns = current->timer_slack_ns; |
1418 | ||
5995477a | 1419 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1420 | acct_clear_integrals(p); |
1421 | ||
f06febc9 | 1422 | posix_cpu_timers_init(p); |
1da177e4 | 1423 | |
ccbf62d8 | 1424 | p->start_time = ktime_get_ns(); |
57e0be04 | 1425 | p->real_start_time = ktime_get_boot_ns(); |
1da177e4 | 1426 | p->io_context = NULL; |
1da177e4 | 1427 | p->audit_context = NULL; |
b4f48b63 | 1428 | cgroup_fork(p); |
1da177e4 | 1429 | #ifdef CONFIG_NUMA |
846a16bf | 1430 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
1431 | if (IS_ERR(p->mempolicy)) { |
1432 | retval = PTR_ERR(p->mempolicy); | |
1433 | p->mempolicy = NULL; | |
e8604cb4 | 1434 | goto bad_fork_cleanup_threadgroup_lock; |
fb0a685c | 1435 | } |
1da177e4 | 1436 | #endif |
778d3b0f MH |
1437 | #ifdef CONFIG_CPUSETS |
1438 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
1439 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
cc9a6c87 | 1440 | seqcount_init(&p->mems_allowed_seq); |
778d3b0f | 1441 | #endif |
de30a2b3 IM |
1442 | #ifdef CONFIG_TRACE_IRQFLAGS |
1443 | p->irq_events = 0; | |
1444 | p->hardirqs_enabled = 0; | |
1445 | p->hardirq_enable_ip = 0; | |
1446 | p->hardirq_enable_event = 0; | |
1447 | p->hardirq_disable_ip = _THIS_IP_; | |
1448 | p->hardirq_disable_event = 0; | |
1449 | p->softirqs_enabled = 1; | |
1450 | p->softirq_enable_ip = _THIS_IP_; | |
1451 | p->softirq_enable_event = 0; | |
1452 | p->softirq_disable_ip = 0; | |
1453 | p->softirq_disable_event = 0; | |
1454 | p->hardirq_context = 0; | |
1455 | p->softirq_context = 0; | |
1456 | #endif | |
8bcbde54 DH |
1457 | |
1458 | p->pagefault_disabled = 0; | |
1459 | ||
fbb9ce95 IM |
1460 | #ifdef CONFIG_LOCKDEP |
1461 | p->lockdep_depth = 0; /* no locks held yet */ | |
1462 | p->curr_chain_key = 0; | |
1463 | p->lockdep_recursion = 0; | |
1464 | #endif | |
1da177e4 | 1465 | |
408894ee IM |
1466 | #ifdef CONFIG_DEBUG_MUTEXES |
1467 | p->blocked_on = NULL; /* not blocked yet */ | |
1468 | #endif | |
cafe5635 KO |
1469 | #ifdef CONFIG_BCACHE |
1470 | p->sequential_io = 0; | |
1471 | p->sequential_io_avg = 0; | |
1472 | #endif | |
0f481406 | 1473 | |
3c90e6e9 | 1474 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
aab03e05 DF |
1475 | retval = sched_fork(clone_flags, p); |
1476 | if (retval) | |
1477 | goto bad_fork_cleanup_policy; | |
6ab423e0 | 1478 | |
cdd6c482 | 1479 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1480 | if (retval) |
1481 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
1482 | retval = audit_alloc(p); |
1483 | if (retval) | |
6c72e350 | 1484 | goto bad_fork_cleanup_perf; |
1da177e4 | 1485 | /* copy all the process information */ |
ab602f79 | 1486 | shm_init_task(p); |
fb0a685c DRO |
1487 | retval = copy_semundo(clone_flags, p); |
1488 | if (retval) | |
1da177e4 | 1489 | goto bad_fork_cleanup_audit; |
fb0a685c DRO |
1490 | retval = copy_files(clone_flags, p); |
1491 | if (retval) | |
1da177e4 | 1492 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
1493 | retval = copy_fs(clone_flags, p); |
1494 | if (retval) | |
1da177e4 | 1495 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
1496 | retval = copy_sighand(clone_flags, p); |
1497 | if (retval) | |
1da177e4 | 1498 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
1499 | retval = copy_signal(clone_flags, p); |
1500 | if (retval) | |
1da177e4 | 1501 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
1502 | retval = copy_mm(clone_flags, p); |
1503 | if (retval) | |
1da177e4 | 1504 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
1505 | retval = copy_namespaces(clone_flags, p); |
1506 | if (retval) | |
d84f4f99 | 1507 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
1508 | retval = copy_io(clone_flags, p); |
1509 | if (retval) | |
fd0928df | 1510 | goto bad_fork_cleanup_namespaces; |
3033f14a | 1511 | retval = copy_thread_tls(clone_flags, stack_start, stack_size, p, tls); |
1da177e4 | 1512 | if (retval) |
fd0928df | 1513 | goto bad_fork_cleanup_io; |
1da177e4 | 1514 | |
425fb2b4 | 1515 | if (pid != &init_struct_pid) { |
c2b1df2e | 1516 | pid = alloc_pid(p->nsproxy->pid_ns_for_children); |
35f71bc0 MH |
1517 | if (IS_ERR(pid)) { |
1518 | retval = PTR_ERR(pid); | |
0740aa5f | 1519 | goto bad_fork_cleanup_thread; |
35f71bc0 | 1520 | } |
425fb2b4 PE |
1521 | } |
1522 | ||
1da177e4 LT |
1523 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1524 | /* | |
1525 | * Clear TID on mm_release()? | |
1526 | */ | |
fb0a685c | 1527 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL; |
73c10101 JA |
1528 | #ifdef CONFIG_BLOCK |
1529 | p->plug = NULL; | |
1530 | #endif | |
42b2dd0a | 1531 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1532 | p->robust_list = NULL; |
1533 | #ifdef CONFIG_COMPAT | |
1534 | p->compat_robust_list = NULL; | |
1535 | #endif | |
c87e2837 IM |
1536 | INIT_LIST_HEAD(&p->pi_state_list); |
1537 | p->pi_state_cache = NULL; | |
42b2dd0a | 1538 | #endif |
f9a3879a GM |
1539 | /* |
1540 | * sigaltstack should be cleared when sharing the same VM | |
1541 | */ | |
1542 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
2a742138 | 1543 | sas_ss_reset(p); |
f9a3879a | 1544 | |
1da177e4 | 1545 | /* |
6580807d ON |
1546 | * Syscall tracing and stepping should be turned off in the |
1547 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1548 | */ |
6580807d | 1549 | user_disable_single_step(p); |
1da177e4 | 1550 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1551 | #ifdef TIF_SYSCALL_EMU |
1552 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1553 | #endif | |
9745512c | 1554 | clear_all_latency_tracing(p); |
1da177e4 | 1555 | |
1da177e4 | 1556 | /* ok, now we should be set up.. */ |
18c830df ON |
1557 | p->pid = pid_nr(pid); |
1558 | if (clone_flags & CLONE_THREAD) { | |
5f8aadd8 | 1559 | p->exit_signal = -1; |
18c830df ON |
1560 | p->group_leader = current->group_leader; |
1561 | p->tgid = current->tgid; | |
1562 | } else { | |
1563 | if (clone_flags & CLONE_PARENT) | |
1564 | p->exit_signal = current->group_leader->exit_signal; | |
1565 | else | |
1566 | p->exit_signal = (clone_flags & CSIGNAL); | |
1567 | p->group_leader = p; | |
1568 | p->tgid = p->pid; | |
1569 | } | |
5f8aadd8 | 1570 | |
9d823e8f WF |
1571 | p->nr_dirtied = 0; |
1572 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 1573 | p->dirty_paused_when = 0; |
9d823e8f | 1574 | |
bb8cbbfe | 1575 | p->pdeath_signal = 0; |
47e65328 | 1576 | INIT_LIST_HEAD(&p->thread_group); |
158e1645 | 1577 | p->task_works = NULL; |
1da177e4 | 1578 | |
568ac888 | 1579 | threadgroup_change_begin(current); |
7e47682e AS |
1580 | /* |
1581 | * Ensure that the cgroup subsystem policies allow the new process to be | |
1582 | * forked. It should be noted the the new process's css_set can be changed | |
1583 | * between here and cgroup_post_fork() if an organisation operation is in | |
1584 | * progress. | |
1585 | */ | |
b53202e6 | 1586 | retval = cgroup_can_fork(p); |
7e47682e AS |
1587 | if (retval) |
1588 | goto bad_fork_free_pid; | |
1589 | ||
18c830df ON |
1590 | /* |
1591 | * Make it visible to the rest of the system, but dont wake it up yet. | |
1592 | * Need tasklist lock for parent etc handling! | |
1593 | */ | |
1da177e4 LT |
1594 | write_lock_irq(&tasklist_lock); |
1595 | ||
1da177e4 | 1596 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1597 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1598 | p->real_parent = current->real_parent; |
2d5516cb ON |
1599 | p->parent_exec_id = current->parent_exec_id; |
1600 | } else { | |
1da177e4 | 1601 | p->real_parent = current; |
2d5516cb ON |
1602 | p->parent_exec_id = current->self_exec_id; |
1603 | } | |
1da177e4 | 1604 | |
3f17da69 | 1605 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 | 1606 | |
dbd95212 KC |
1607 | /* |
1608 | * Copy seccomp details explicitly here, in case they were changed | |
1609 | * before holding sighand lock. | |
1610 | */ | |
1611 | copy_seccomp(p); | |
1612 | ||
4a2c7a78 ON |
1613 | /* |
1614 | * Process group and session signals need to be delivered to just the | |
1615 | * parent before the fork or both the parent and the child after the | |
1616 | * fork. Restart if a signal comes in before we add the new process to | |
1617 | * it's process group. | |
1618 | * A fatal signal pending means that current will exit, so the new | |
1619 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
fb0a685c | 1620 | */ |
23ff4440 | 1621 | recalc_sigpending(); |
4a2c7a78 ON |
1622 | if (signal_pending(current)) { |
1623 | spin_unlock(¤t->sighand->siglock); | |
1624 | write_unlock_irq(&tasklist_lock); | |
1625 | retval = -ERESTARTNOINTR; | |
7e47682e | 1626 | goto bad_fork_cancel_cgroup; |
4a2c7a78 ON |
1627 | } |
1628 | ||
73b9ebfe | 1629 | if (likely(p->pid)) { |
4b9d33e6 | 1630 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe | 1631 | |
81907739 | 1632 | init_task_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1633 | if (thread_group_leader(p)) { |
81907739 ON |
1634 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1635 | init_task_pid(p, PIDTYPE_SID, task_session(current)); | |
1636 | ||
1c4042c2 | 1637 | if (is_child_reaper(pid)) { |
17cf22c3 | 1638 | ns_of_pid(pid)->child_reaper = p; |
1c4042c2 EB |
1639 | p->signal->flags |= SIGNAL_UNKILLABLE; |
1640 | } | |
73b9ebfe | 1641 | |
fea9d175 | 1642 | p->signal->leader_pid = pid; |
9c9f4ded | 1643 | p->signal->tty = tty_kref_get(current->signal->tty); |
9cd80bbb | 1644 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 1645 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
81907739 ON |
1646 | attach_pid(p, PIDTYPE_PGID); |
1647 | attach_pid(p, PIDTYPE_SID); | |
909ea964 | 1648 | __this_cpu_inc(process_counts); |
80628ca0 ON |
1649 | } else { |
1650 | current->signal->nr_threads++; | |
1651 | atomic_inc(¤t->signal->live); | |
1652 | atomic_inc(¤t->signal->sigcnt); | |
80628ca0 ON |
1653 | list_add_tail_rcu(&p->thread_group, |
1654 | &p->group_leader->thread_group); | |
0c740d0a ON |
1655 | list_add_tail_rcu(&p->thread_node, |
1656 | &p->signal->thread_head); | |
73b9ebfe | 1657 | } |
81907739 | 1658 | attach_pid(p, PIDTYPE_PID); |
73b9ebfe | 1659 | nr_threads++; |
1da177e4 LT |
1660 | } |
1661 | ||
1da177e4 | 1662 | total_forks++; |
3f17da69 | 1663 | spin_unlock(¤t->sighand->siglock); |
4af4206b | 1664 | syscall_tracepoint_update(p); |
1da177e4 | 1665 | write_unlock_irq(&tasklist_lock); |
4af4206b | 1666 | |
c13cf856 | 1667 | proc_fork_connector(p); |
b53202e6 | 1668 | cgroup_post_fork(p); |
c9e75f04 | 1669 | threadgroup_change_end(current); |
cdd6c482 | 1670 | perf_event_fork(p); |
43d2b113 KH |
1671 | |
1672 | trace_task_newtask(p, clone_flags); | |
3ab67966 | 1673 | uprobe_copy_process(p, clone_flags); |
43d2b113 | 1674 | |
1da177e4 LT |
1675 | return p; |
1676 | ||
7e47682e | 1677 | bad_fork_cancel_cgroup: |
b53202e6 | 1678 | cgroup_cancel_fork(p); |
425fb2b4 | 1679 | bad_fork_free_pid: |
568ac888 | 1680 | threadgroup_change_end(current); |
425fb2b4 PE |
1681 | if (pid != &init_struct_pid) |
1682 | free_pid(pid); | |
0740aa5f JS |
1683 | bad_fork_cleanup_thread: |
1684 | exit_thread(p); | |
fd0928df | 1685 | bad_fork_cleanup_io: |
b69f2292 LR |
1686 | if (p->io_context) |
1687 | exit_io_context(p); | |
ab516013 | 1688 | bad_fork_cleanup_namespaces: |
444f378b | 1689 | exit_task_namespaces(p); |
1da177e4 | 1690 | bad_fork_cleanup_mm: |
c9f01245 | 1691 | if (p->mm) |
1da177e4 LT |
1692 | mmput(p->mm); |
1693 | bad_fork_cleanup_signal: | |
4ab6c083 | 1694 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 1695 | free_signal_struct(p->signal); |
1da177e4 | 1696 | bad_fork_cleanup_sighand: |
a7e5328a | 1697 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1698 | bad_fork_cleanup_fs: |
1699 | exit_fs(p); /* blocking */ | |
1700 | bad_fork_cleanup_files: | |
1701 | exit_files(p); /* blocking */ | |
1702 | bad_fork_cleanup_semundo: | |
1703 | exit_sem(p); | |
1704 | bad_fork_cleanup_audit: | |
1705 | audit_free(p); | |
6c72e350 | 1706 | bad_fork_cleanup_perf: |
cdd6c482 | 1707 | perf_event_free_task(p); |
6c72e350 | 1708 | bad_fork_cleanup_policy: |
1da177e4 | 1709 | #ifdef CONFIG_NUMA |
f0be3d32 | 1710 | mpol_put(p->mempolicy); |
e8604cb4 | 1711 | bad_fork_cleanup_threadgroup_lock: |
1da177e4 | 1712 | #endif |
35df17c5 | 1713 | delayacct_tsk_free(p); |
1da177e4 | 1714 | bad_fork_cleanup_count: |
d84f4f99 | 1715 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1716 | exit_creds(p); |
1da177e4 LT |
1717 | bad_fork_free: |
1718 | free_task(p); | |
fe7d37d1 ON |
1719 | fork_out: |
1720 | return ERR_PTR(retval); | |
1da177e4 LT |
1721 | } |
1722 | ||
f106eee1 ON |
1723 | static inline void init_idle_pids(struct pid_link *links) |
1724 | { | |
1725 | enum pid_type type; | |
1726 | ||
1727 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
1728 | INIT_HLIST_NODE(&links[type].node); /* not really needed */ | |
1729 | links[type].pid = &init_struct_pid; | |
1730 | } | |
1731 | } | |
1732 | ||
0db0628d | 1733 | struct task_struct *fork_idle(int cpu) |
1da177e4 | 1734 | { |
36c8b586 | 1735 | struct task_struct *task; |
725fc629 AK |
1736 | task = copy_process(CLONE_VM, 0, 0, NULL, &init_struct_pid, 0, 0, |
1737 | cpu_to_node(cpu)); | |
f106eee1 ON |
1738 | if (!IS_ERR(task)) { |
1739 | init_idle_pids(task->pids); | |
753ca4f3 | 1740 | init_idle(task, cpu); |
f106eee1 | 1741 | } |
73b9ebfe | 1742 | |
1da177e4 LT |
1743 | return task; |
1744 | } | |
1745 | ||
1da177e4 LT |
1746 | /* |
1747 | * Ok, this is the main fork-routine. | |
1748 | * | |
1749 | * It copies the process, and if successful kick-starts | |
1750 | * it and waits for it to finish using the VM if required. | |
1751 | */ | |
3033f14a | 1752 | long _do_fork(unsigned long clone_flags, |
1da177e4 | 1753 | unsigned long stack_start, |
1da177e4 LT |
1754 | unsigned long stack_size, |
1755 | int __user *parent_tidptr, | |
3033f14a JT |
1756 | int __user *child_tidptr, |
1757 | unsigned long tls) | |
1da177e4 LT |
1758 | { |
1759 | struct task_struct *p; | |
1760 | int trace = 0; | |
92476d7f | 1761 | long nr; |
1da177e4 | 1762 | |
09a05394 | 1763 | /* |
4b9d33e6 TH |
1764 | * Determine whether and which event to report to ptracer. When |
1765 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
1766 | * requested, no event is reported; otherwise, report if the event | |
1767 | * for the type of forking is enabled. | |
09a05394 | 1768 | */ |
e80d6661 | 1769 | if (!(clone_flags & CLONE_UNTRACED)) { |
4b9d33e6 TH |
1770 | if (clone_flags & CLONE_VFORK) |
1771 | trace = PTRACE_EVENT_VFORK; | |
1772 | else if ((clone_flags & CSIGNAL) != SIGCHLD) | |
1773 | trace = PTRACE_EVENT_CLONE; | |
1774 | else | |
1775 | trace = PTRACE_EVENT_FORK; | |
1776 | ||
1777 | if (likely(!ptrace_event_enabled(current, trace))) | |
1778 | trace = 0; | |
1779 | } | |
1da177e4 | 1780 | |
62e791c1 | 1781 | p = copy_process(clone_flags, stack_start, stack_size, |
725fc629 | 1782 | child_tidptr, NULL, trace, tls, NUMA_NO_NODE); |
1da177e4 LT |
1783 | /* |
1784 | * Do this prior waking up the new thread - the thread pointer | |
1785 | * might get invalid after that point, if the thread exits quickly. | |
1786 | */ | |
1787 | if (!IS_ERR(p)) { | |
1788 | struct completion vfork; | |
4e52365f | 1789 | struct pid *pid; |
1da177e4 | 1790 | |
0a16b607 MD |
1791 | trace_sched_process_fork(current, p); |
1792 | ||
4e52365f MD |
1793 | pid = get_task_pid(p, PIDTYPE_PID); |
1794 | nr = pid_vnr(pid); | |
30e49c26 PE |
1795 | |
1796 | if (clone_flags & CLONE_PARENT_SETTID) | |
1797 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1798 | |
1da177e4 LT |
1799 | if (clone_flags & CLONE_VFORK) { |
1800 | p->vfork_done = &vfork; | |
1801 | init_completion(&vfork); | |
d68b46fe | 1802 | get_task_struct(p); |
1da177e4 LT |
1803 | } |
1804 | ||
3e51e3ed | 1805 | wake_up_new_task(p); |
1da177e4 | 1806 | |
4b9d33e6 TH |
1807 | /* forking complete and child started to run, tell ptracer */ |
1808 | if (unlikely(trace)) | |
4e52365f | 1809 | ptrace_event_pid(trace, pid); |
09a05394 | 1810 | |
1da177e4 | 1811 | if (clone_flags & CLONE_VFORK) { |
d68b46fe | 1812 | if (!wait_for_vfork_done(p, &vfork)) |
4e52365f | 1813 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid); |
1da177e4 | 1814 | } |
4e52365f MD |
1815 | |
1816 | put_pid(pid); | |
1da177e4 | 1817 | } else { |
92476d7f | 1818 | nr = PTR_ERR(p); |
1da177e4 | 1819 | } |
92476d7f | 1820 | return nr; |
1da177e4 LT |
1821 | } |
1822 | ||
3033f14a JT |
1823 | #ifndef CONFIG_HAVE_COPY_THREAD_TLS |
1824 | /* For compatibility with architectures that call do_fork directly rather than | |
1825 | * using the syscall entry points below. */ | |
1826 | long do_fork(unsigned long clone_flags, | |
1827 | unsigned long stack_start, | |
1828 | unsigned long stack_size, | |
1829 | int __user *parent_tidptr, | |
1830 | int __user *child_tidptr) | |
1831 | { | |
1832 | return _do_fork(clone_flags, stack_start, stack_size, | |
1833 | parent_tidptr, child_tidptr, 0); | |
1834 | } | |
1835 | #endif | |
1836 | ||
2aa3a7f8 AV |
1837 | /* |
1838 | * Create a kernel thread. | |
1839 | */ | |
1840 | pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
1841 | { | |
3033f14a JT |
1842 | return _do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn, |
1843 | (unsigned long)arg, NULL, NULL, 0); | |
2aa3a7f8 | 1844 | } |
2aa3a7f8 | 1845 | |
d2125043 AV |
1846 | #ifdef __ARCH_WANT_SYS_FORK |
1847 | SYSCALL_DEFINE0(fork) | |
1848 | { | |
1849 | #ifdef CONFIG_MMU | |
3033f14a | 1850 | return _do_fork(SIGCHLD, 0, 0, NULL, NULL, 0); |
d2125043 AV |
1851 | #else |
1852 | /* can not support in nommu mode */ | |
5d59e182 | 1853 | return -EINVAL; |
d2125043 AV |
1854 | #endif |
1855 | } | |
1856 | #endif | |
1857 | ||
1858 | #ifdef __ARCH_WANT_SYS_VFORK | |
1859 | SYSCALL_DEFINE0(vfork) | |
1860 | { | |
3033f14a JT |
1861 | return _do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0, |
1862 | 0, NULL, NULL, 0); | |
d2125043 AV |
1863 | } |
1864 | #endif | |
1865 | ||
1866 | #ifdef __ARCH_WANT_SYS_CLONE | |
1867 | #ifdef CONFIG_CLONE_BACKWARDS | |
1868 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
1869 | int __user *, parent_tidptr, | |
3033f14a | 1870 | unsigned long, tls, |
d2125043 AV |
1871 | int __user *, child_tidptr) |
1872 | #elif defined(CONFIG_CLONE_BACKWARDS2) | |
1873 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags, | |
1874 | int __user *, parent_tidptr, | |
1875 | int __user *, child_tidptr, | |
3033f14a | 1876 | unsigned long, tls) |
dfa9771a MS |
1877 | #elif defined(CONFIG_CLONE_BACKWARDS3) |
1878 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp, | |
1879 | int, stack_size, | |
1880 | int __user *, parent_tidptr, | |
1881 | int __user *, child_tidptr, | |
3033f14a | 1882 | unsigned long, tls) |
d2125043 AV |
1883 | #else |
1884 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, | |
1885 | int __user *, parent_tidptr, | |
1886 | int __user *, child_tidptr, | |
3033f14a | 1887 | unsigned long, tls) |
d2125043 AV |
1888 | #endif |
1889 | { | |
3033f14a | 1890 | return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr, tls); |
d2125043 AV |
1891 | } |
1892 | #endif | |
1893 | ||
5fd63b30 RT |
1894 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1895 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1896 | #endif | |
1897 | ||
51cc5068 | 1898 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1899 | { |
1900 | struct sighand_struct *sighand = data; | |
1901 | ||
a35afb83 | 1902 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1903 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1904 | } |
1905 | ||
1da177e4 LT |
1906 | void __init proc_caches_init(void) |
1907 | { | |
1908 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1909 | sizeof(struct sighand_struct), 0, | |
2dff4405 | 1910 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
5d097056 | 1911 | SLAB_NOTRACK|SLAB_ACCOUNT, sighand_ctor); |
1da177e4 LT |
1912 | signal_cachep = kmem_cache_create("signal_cache", |
1913 | sizeof(struct signal_struct), 0, | |
5d097056 VD |
1914 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
1915 | NULL); | |
20c2df83 | 1916 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 1917 | sizeof(struct files_struct), 0, |
5d097056 VD |
1918 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
1919 | NULL); | |
20c2df83 | 1920 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 1921 | sizeof(struct fs_struct), 0, |
5d097056 VD |
1922 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
1923 | NULL); | |
6345d24d LT |
1924 | /* |
1925 | * FIXME! The "sizeof(struct mm_struct)" currently includes the | |
1926 | * whole struct cpumask for the OFFSTACK case. We could change | |
1927 | * this to *only* allocate as much of it as required by the | |
1928 | * maximum number of CPU's we can ever have. The cpumask_allocation | |
1929 | * is at the end of the structure, exactly for that reason. | |
1930 | */ | |
1da177e4 | 1931 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1932 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
5d097056 VD |
1933 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, |
1934 | NULL); | |
1935 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT); | |
8feae131 | 1936 | mmap_init(); |
66577193 | 1937 | nsproxy_cache_init(); |
1da177e4 | 1938 | } |
cf2e340f | 1939 | |
cf2e340f | 1940 | /* |
9bfb23fc | 1941 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 1942 | */ |
9bfb23fc | 1943 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 1944 | { |
9bfb23fc ON |
1945 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
1946 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
50804fe3 | 1947 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET| |
a79a908f | 1948 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP)) |
9bfb23fc | 1949 | return -EINVAL; |
cf2e340f | 1950 | /* |
12c641ab EB |
1951 | * Not implemented, but pretend it works if there is nothing |
1952 | * to unshare. Note that unsharing the address space or the | |
1953 | * signal handlers also need to unshare the signal queues (aka | |
1954 | * CLONE_THREAD). | |
cf2e340f | 1955 | */ |
9bfb23fc | 1956 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
12c641ab EB |
1957 | if (!thread_group_empty(current)) |
1958 | return -EINVAL; | |
1959 | } | |
1960 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { | |
1961 | if (atomic_read(¤t->sighand->count) > 1) | |
1962 | return -EINVAL; | |
1963 | } | |
1964 | if (unshare_flags & CLONE_VM) { | |
1965 | if (!current_is_single_threaded()) | |
9bfb23fc ON |
1966 | return -EINVAL; |
1967 | } | |
cf2e340f JD |
1968 | |
1969 | return 0; | |
1970 | } | |
1971 | ||
1972 | /* | |
99d1419d | 1973 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1974 | */ |
1975 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1976 | { | |
1977 | struct fs_struct *fs = current->fs; | |
1978 | ||
498052bb AV |
1979 | if (!(unshare_flags & CLONE_FS) || !fs) |
1980 | return 0; | |
1981 | ||
1982 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1983 | if (fs->users == 1) | |
1984 | return 0; | |
1985 | ||
1986 | *new_fsp = copy_fs_struct(fs); | |
1987 | if (!*new_fsp) | |
1988 | return -ENOMEM; | |
cf2e340f JD |
1989 | |
1990 | return 0; | |
1991 | } | |
1992 | ||
cf2e340f | 1993 | /* |
a016f338 | 1994 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1995 | */ |
1996 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1997 | { | |
1998 | struct files_struct *fd = current->files; | |
a016f338 | 1999 | int error = 0; |
cf2e340f JD |
2000 | |
2001 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
2002 | (fd && atomic_read(&fd->count) > 1)) { |
2003 | *new_fdp = dup_fd(fd, &error); | |
2004 | if (!*new_fdp) | |
2005 | return error; | |
2006 | } | |
cf2e340f JD |
2007 | |
2008 | return 0; | |
2009 | } | |
2010 | ||
cf2e340f JD |
2011 | /* |
2012 | * unshare allows a process to 'unshare' part of the process | |
2013 | * context which was originally shared using clone. copy_* | |
2014 | * functions used by do_fork() cannot be used here directly | |
2015 | * because they modify an inactive task_struct that is being | |
2016 | * constructed. Here we are modifying the current, active, | |
2017 | * task_struct. | |
2018 | */ | |
6559eed8 | 2019 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f | 2020 | { |
cf2e340f | 2021 | struct fs_struct *fs, *new_fs = NULL; |
cf2e340f | 2022 | struct files_struct *fd, *new_fd = NULL; |
b2e0d987 | 2023 | struct cred *new_cred = NULL; |
cf7b708c | 2024 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 2025 | int do_sysvsem = 0; |
9bfb23fc | 2026 | int err; |
cf2e340f | 2027 | |
b2e0d987 | 2028 | /* |
faf00da5 EB |
2029 | * If unsharing a user namespace must also unshare the thread group |
2030 | * and unshare the filesystem root and working directories. | |
b2e0d987 EB |
2031 | */ |
2032 | if (unshare_flags & CLONE_NEWUSER) | |
e66eded8 | 2033 | unshare_flags |= CLONE_THREAD | CLONE_FS; |
50804fe3 EB |
2034 | /* |
2035 | * If unsharing vm, must also unshare signal handlers. | |
2036 | */ | |
2037 | if (unshare_flags & CLONE_VM) | |
2038 | unshare_flags |= CLONE_SIGHAND; | |
12c641ab EB |
2039 | /* |
2040 | * If unsharing a signal handlers, must also unshare the signal queues. | |
2041 | */ | |
2042 | if (unshare_flags & CLONE_SIGHAND) | |
2043 | unshare_flags |= CLONE_THREAD; | |
9bfb23fc ON |
2044 | /* |
2045 | * If unsharing namespace, must also unshare filesystem information. | |
2046 | */ | |
2047 | if (unshare_flags & CLONE_NEWNS) | |
2048 | unshare_flags |= CLONE_FS; | |
50804fe3 EB |
2049 | |
2050 | err = check_unshare_flags(unshare_flags); | |
2051 | if (err) | |
2052 | goto bad_unshare_out; | |
6013f67f MS |
2053 | /* |
2054 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
2055 | * to a new ipc namespace, the semaphore arrays from the old | |
2056 | * namespace are unreachable. | |
2057 | */ | |
2058 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 2059 | do_sysvsem = 1; |
fb0a685c DRO |
2060 | err = unshare_fs(unshare_flags, &new_fs); |
2061 | if (err) | |
9bfb23fc | 2062 | goto bad_unshare_out; |
fb0a685c DRO |
2063 | err = unshare_fd(unshare_flags, &new_fd); |
2064 | if (err) | |
9bfb23fc | 2065 | goto bad_unshare_cleanup_fs; |
b2e0d987 | 2066 | err = unshare_userns(unshare_flags, &new_cred); |
fb0a685c | 2067 | if (err) |
9edff4ab | 2068 | goto bad_unshare_cleanup_fd; |
b2e0d987 EB |
2069 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
2070 | new_cred, new_fs); | |
2071 | if (err) | |
2072 | goto bad_unshare_cleanup_cred; | |
c0b2fc31 | 2073 | |
b2e0d987 | 2074 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { |
9edff4ab MS |
2075 | if (do_sysvsem) { |
2076 | /* | |
2077 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
2078 | */ | |
2079 | exit_sem(current); | |
2080 | } | |
ab602f79 JM |
2081 | if (unshare_flags & CLONE_NEWIPC) { |
2082 | /* Orphan segments in old ns (see sem above). */ | |
2083 | exit_shm(current); | |
2084 | shm_init_task(current); | |
2085 | } | |
ab516013 | 2086 | |
6f977e6b | 2087 | if (new_nsproxy) |
cf7b708c | 2088 | switch_task_namespaces(current, new_nsproxy); |
cf2e340f | 2089 | |
cf7b708c PE |
2090 | task_lock(current); |
2091 | ||
cf2e340f JD |
2092 | if (new_fs) { |
2093 | fs = current->fs; | |
2a4419b5 | 2094 | spin_lock(&fs->lock); |
cf2e340f | 2095 | current->fs = new_fs; |
498052bb AV |
2096 | if (--fs->users) |
2097 | new_fs = NULL; | |
2098 | else | |
2099 | new_fs = fs; | |
2a4419b5 | 2100 | spin_unlock(&fs->lock); |
cf2e340f JD |
2101 | } |
2102 | ||
cf2e340f JD |
2103 | if (new_fd) { |
2104 | fd = current->files; | |
2105 | current->files = new_fd; | |
2106 | new_fd = fd; | |
2107 | } | |
2108 | ||
2109 | task_unlock(current); | |
b2e0d987 EB |
2110 | |
2111 | if (new_cred) { | |
2112 | /* Install the new user namespace */ | |
2113 | commit_creds(new_cred); | |
2114 | new_cred = NULL; | |
2115 | } | |
cf2e340f JD |
2116 | } |
2117 | ||
b2e0d987 EB |
2118 | bad_unshare_cleanup_cred: |
2119 | if (new_cred) | |
2120 | put_cred(new_cred); | |
cf2e340f JD |
2121 | bad_unshare_cleanup_fd: |
2122 | if (new_fd) | |
2123 | put_files_struct(new_fd); | |
2124 | ||
cf2e340f JD |
2125 | bad_unshare_cleanup_fs: |
2126 | if (new_fs) | |
498052bb | 2127 | free_fs_struct(new_fs); |
cf2e340f | 2128 | |
cf2e340f JD |
2129 | bad_unshare_out: |
2130 | return err; | |
2131 | } | |
3b125388 AV |
2132 | |
2133 | /* | |
2134 | * Helper to unshare the files of the current task. | |
2135 | * We don't want to expose copy_files internals to | |
2136 | * the exec layer of the kernel. | |
2137 | */ | |
2138 | ||
2139 | int unshare_files(struct files_struct **displaced) | |
2140 | { | |
2141 | struct task_struct *task = current; | |
50704516 | 2142 | struct files_struct *copy = NULL; |
3b125388 AV |
2143 | int error; |
2144 | ||
2145 | error = unshare_fd(CLONE_FILES, ©); | |
2146 | if (error || !copy) { | |
2147 | *displaced = NULL; | |
2148 | return error; | |
2149 | } | |
2150 | *displaced = task->files; | |
2151 | task_lock(task); | |
2152 | task->files = copy; | |
2153 | task_unlock(task); | |
2154 | return 0; | |
2155 | } | |
16db3d3f HS |
2156 | |
2157 | int sysctl_max_threads(struct ctl_table *table, int write, | |
2158 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2159 | { | |
2160 | struct ctl_table t; | |
2161 | int ret; | |
2162 | int threads = max_threads; | |
2163 | int min = MIN_THREADS; | |
2164 | int max = MAX_THREADS; | |
2165 | ||
2166 | t = *table; | |
2167 | t.data = &threads; | |
2168 | t.extra1 = &min; | |
2169 | t.extra2 = &max; | |
2170 | ||
2171 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2172 | if (ret || !write) | |
2173 | return ret; | |
2174 | ||
2175 | set_max_threads(threads); | |
2176 | ||
2177 | return 0; | |
2178 | } |