Commit | Line | Data |
---|---|---|
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> |
ab516013 | 31 | #include <linux/nsproxy.h> |
c59ede7b | 32 | #include <linux/capability.h> |
1da177e4 | 33 | #include <linux/cpu.h> |
b4f48b63 | 34 | #include <linux/cgroup.h> |
1da177e4 | 35 | #include <linux/security.h> |
a1e78772 | 36 | #include <linux/hugetlb.h> |
e2cfabdf | 37 | #include <linux/seccomp.h> |
1da177e4 LT |
38 | #include <linux/swap.h> |
39 | #include <linux/syscalls.h> | |
40 | #include <linux/jiffies.h> | |
41 | #include <linux/futex.h> | |
8141c7f3 | 42 | #include <linux/compat.h> |
207205a2 | 43 | #include <linux/kthread.h> |
7c3ab738 | 44 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 45 | #include <linux/rcupdate.h> |
1da177e4 LT |
46 | #include <linux/ptrace.h> |
47 | #include <linux/mount.h> | |
48 | #include <linux/audit.h> | |
78fb7466 | 49 | #include <linux/memcontrol.h> |
f201ae23 | 50 | #include <linux/ftrace.h> |
5e2bf014 | 51 | #include <linux/proc_fs.h> |
1da177e4 LT |
52 | #include <linux/profile.h> |
53 | #include <linux/rmap.h> | |
f8af4da3 | 54 | #include <linux/ksm.h> |
1da177e4 | 55 | #include <linux/acct.h> |
8f0ab514 | 56 | #include <linux/tsacct_kern.h> |
9f46080c | 57 | #include <linux/cn_proc.h> |
ba96a0c8 | 58 | #include <linux/freezer.h> |
ca74e92b | 59 | #include <linux/delayacct.h> |
ad4ecbcb | 60 | #include <linux/taskstats_kern.h> |
0a425405 | 61 | #include <linux/random.h> |
522ed776 | 62 | #include <linux/tty.h> |
fd0928df | 63 | #include <linux/blkdev.h> |
5ad4e53b | 64 | #include <linux/fs_struct.h> |
7c9f8861 | 65 | #include <linux/magic.h> |
cdd6c482 | 66 | #include <linux/perf_event.h> |
42c4ab41 | 67 | #include <linux/posix-timers.h> |
8e7cac79 | 68 | #include <linux/user-return-notifier.h> |
3d5992d2 | 69 | #include <linux/oom.h> |
ba76149f | 70 | #include <linux/khugepaged.h> |
d80e731e | 71 | #include <linux/signalfd.h> |
0326f5a9 | 72 | #include <linux/uprobes.h> |
1da177e4 LT |
73 | |
74 | #include <asm/pgtable.h> | |
75 | #include <asm/pgalloc.h> | |
76 | #include <asm/uaccess.h> | |
77 | #include <asm/mmu_context.h> | |
78 | #include <asm/cacheflush.h> | |
79 | #include <asm/tlbflush.h> | |
80 | ||
ad8d75ff SR |
81 | #include <trace/events/sched.h> |
82 | ||
43d2b113 KH |
83 | #define CREATE_TRACE_POINTS |
84 | #include <trace/events/task.h> | |
85 | ||
1da177e4 LT |
86 | /* |
87 | * Protected counters by write_lock_irq(&tasklist_lock) | |
88 | */ | |
89 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
fb0a685c | 90 | int nr_threads; /* The idle threads do not count.. */ |
1da177e4 LT |
91 | |
92 | int max_threads; /* tunable limit on nr_threads */ | |
93 | ||
94 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
95 | ||
c59923a1 | 96 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
97 | |
98 | #ifdef CONFIG_PROVE_RCU | |
99 | int lockdep_tasklist_lock_is_held(void) | |
100 | { | |
101 | return lockdep_is_held(&tasklist_lock); | |
102 | } | |
103 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
104 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
105 | |
106 | int nr_processes(void) | |
107 | { | |
108 | int cpu; | |
109 | int total = 0; | |
110 | ||
1d510750 | 111 | for_each_possible_cpu(cpu) |
1da177e4 LT |
112 | total += per_cpu(process_counts, cpu); |
113 | ||
114 | return total; | |
115 | } | |
116 | ||
f5e10287 | 117 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
e18b890b | 118 | static struct kmem_cache *task_struct_cachep; |
41101809 TG |
119 | |
120 | static inline struct task_struct *alloc_task_struct_node(int node) | |
121 | { | |
122 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); | |
123 | } | |
124 | ||
125 | void __weak arch_release_task_struct(struct task_struct *tsk) { } | |
126 | ||
127 | static inline void free_task_struct(struct task_struct *tsk) | |
128 | { | |
129 | arch_release_task_struct(tsk); | |
130 | kmem_cache_free(task_struct_cachep, tsk); | |
131 | } | |
1da177e4 LT |
132 | #endif |
133 | ||
f5e10287 | 134 | #ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR |
41101809 TG |
135 | void __weak arch_release_thread_info(struct thread_info *ti) { } |
136 | ||
0d15d74a TG |
137 | /* |
138 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a | |
139 | * kmemcache based allocator. | |
140 | */ | |
141 | # if THREAD_SIZE >= PAGE_SIZE | |
b6a84016 ED |
142 | static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, |
143 | int node) | |
b69c49b7 | 144 | { |
2889f608 TG |
145 | struct page *page = alloc_pages_node(node, THREADINFO_GFP, |
146 | THREAD_SIZE_ORDER); | |
b6a84016 ED |
147 | |
148 | return page ? page_address(page) : NULL; | |
b69c49b7 FT |
149 | } |
150 | ||
151 | static inline void free_thread_info(struct thread_info *ti) | |
152 | { | |
41101809 | 153 | arch_release_thread_info(ti); |
b69c49b7 FT |
154 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); |
155 | } | |
0d15d74a TG |
156 | # else |
157 | static struct kmem_cache *thread_info_cache; | |
158 | ||
159 | static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, | |
160 | int node) | |
161 | { | |
162 | return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node); | |
163 | } | |
164 | ||
165 | static void free_thread_info(struct thread_info *ti) | |
166 | { | |
167 | arch_release_thread_info(ti); | |
168 | kmem_cache_free(thread_info_cache, ti); | |
169 | } | |
170 | ||
171 | void thread_info_cache_init(void) | |
172 | { | |
173 | thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE, | |
174 | THREAD_SIZE, 0, NULL); | |
175 | BUG_ON(thread_info_cache == NULL); | |
176 | } | |
177 | # endif | |
b69c49b7 FT |
178 | #endif |
179 | ||
1da177e4 | 180 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 181 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
182 | |
183 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 184 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
185 | |
186 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 187 | struct kmem_cache *files_cachep; |
1da177e4 LT |
188 | |
189 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 190 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
191 | |
192 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 193 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
194 | |
195 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 196 | static struct kmem_cache *mm_cachep; |
1da177e4 | 197 | |
c6a7f572 KM |
198 | static void account_kernel_stack(struct thread_info *ti, int account) |
199 | { | |
200 | struct zone *zone = page_zone(virt_to_page(ti)); | |
201 | ||
202 | mod_zone_page_state(zone, NR_KERNEL_STACK, account); | |
203 | } | |
204 | ||
1da177e4 LT |
205 | void free_task(struct task_struct *tsk) |
206 | { | |
c6a7f572 | 207 | account_kernel_stack(tsk->stack, -1); |
f7e4217b | 208 | free_thread_info(tsk->stack); |
23f78d4a | 209 | rt_mutex_debug_task_free(tsk); |
fb52607a | 210 | ftrace_graph_exit_task(tsk); |
e2cfabdf | 211 | put_seccomp_filter(tsk); |
1da177e4 LT |
212 | free_task_struct(tsk); |
213 | } | |
214 | EXPORT_SYMBOL(free_task); | |
215 | ||
ea6d290c ON |
216 | static inline void free_signal_struct(struct signal_struct *sig) |
217 | { | |
97101eb4 | 218 | taskstats_tgid_free(sig); |
1c5354de | 219 | sched_autogroup_exit(sig); |
ea6d290c ON |
220 | kmem_cache_free(signal_cachep, sig); |
221 | } | |
222 | ||
223 | static inline void put_signal_struct(struct signal_struct *sig) | |
224 | { | |
1c5354de | 225 | if (atomic_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
226 | free_signal_struct(sig); |
227 | } | |
228 | ||
158d9ebd | 229 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 230 | { |
270f722d | 231 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
232 | WARN_ON(atomic_read(&tsk->usage)); |
233 | WARN_ON(tsk == current); | |
234 | ||
1a2a4d06 | 235 | security_task_free(tsk); |
e0e81739 | 236 | exit_creds(tsk); |
35df17c5 | 237 | delayacct_tsk_free(tsk); |
ea6d290c | 238 | put_signal_struct(tsk->signal); |
1da177e4 LT |
239 | |
240 | if (!profile_handoff_task(tsk)) | |
241 | free_task(tsk); | |
242 | } | |
77c100c8 | 243 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 244 | |
6c0a9fa6 | 245 | void __init __weak arch_task_cache_init(void) { } |
61c4628b | 246 | |
1da177e4 LT |
247 | void __init fork_init(unsigned long mempages) |
248 | { | |
f5e10287 | 249 | #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR |
1da177e4 LT |
250 | #ifndef ARCH_MIN_TASKALIGN |
251 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
252 | #endif | |
253 | /* create a slab on which task_structs can be allocated */ | |
254 | task_struct_cachep = | |
255 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
2dff4405 | 256 | ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); |
1da177e4 LT |
257 | #endif |
258 | ||
61c4628b SS |
259 | /* do the arch specific task caches init */ |
260 | arch_task_cache_init(); | |
261 | ||
1da177e4 LT |
262 | /* |
263 | * The default maximum number of threads is set to a safe | |
264 | * value: the thread structures can take up at most half | |
265 | * of memory. | |
266 | */ | |
267 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
268 | ||
269 | /* | |
270 | * we need to allow at least 20 threads to boot a system | |
271 | */ | |
fb0a685c | 272 | if (max_threads < 20) |
1da177e4 LT |
273 | max_threads = 20; |
274 | ||
275 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
276 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
277 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
278 | init_task.signal->rlim[RLIMIT_NPROC]; | |
279 | } | |
280 | ||
61c4628b SS |
281 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
282 | struct task_struct *src) | |
283 | { | |
284 | *dst = *src; | |
285 | return 0; | |
286 | } | |
287 | ||
1da177e4 LT |
288 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
289 | { | |
290 | struct task_struct *tsk; | |
291 | struct thread_info *ti; | |
7c9f8861 | 292 | unsigned long *stackend; |
207205a2 | 293 | int node = tsk_fork_get_node(orig); |
3e26c149 | 294 | int err; |
1da177e4 | 295 | |
504f52b5 | 296 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
297 | if (!tsk) |
298 | return NULL; | |
299 | ||
b6a84016 | 300 | ti = alloc_thread_info_node(tsk, node); |
1da177e4 LT |
301 | if (!ti) { |
302 | free_task_struct(tsk); | |
303 | return NULL; | |
304 | } | |
305 | ||
fb0a685c | 306 | err = arch_dup_task_struct(tsk, orig); |
61c4628b SS |
307 | if (err) |
308 | goto out; | |
309 | ||
f7e4217b | 310 | tsk->stack = ti; |
3e26c149 | 311 | |
10ebffde | 312 | setup_thread_stack(tsk, orig); |
8e7cac79 | 313 | clear_user_return_notifier(tsk); |
f26f9aff | 314 | clear_tsk_need_resched(tsk); |
7c9f8861 ES |
315 | stackend = end_of_stack(tsk); |
316 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1da177e4 | 317 | |
0a425405 AV |
318 | #ifdef CONFIG_CC_STACKPROTECTOR |
319 | tsk->stack_canary = get_random_int(); | |
320 | #endif | |
321 | ||
fb0a685c DRO |
322 | /* |
323 | * One for us, one for whoever does the "release_task()" (usually | |
324 | * parent) | |
325 | */ | |
326 | atomic_set(&tsk->usage, 2); | |
6c5c9341 | 327 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 328 | tsk->btrace_seq = 0; |
6c5c9341 | 329 | #endif |
a0aa7f68 | 330 | tsk->splice_pipe = NULL; |
c6a7f572 KM |
331 | |
332 | account_kernel_stack(ti, 1); | |
333 | ||
1da177e4 | 334 | return tsk; |
61c4628b SS |
335 | |
336 | out: | |
337 | free_thread_info(ti); | |
338 | free_task_struct(tsk); | |
339 | return NULL; | |
1da177e4 LT |
340 | } |
341 | ||
342 | #ifdef CONFIG_MMU | |
a39bc516 | 343 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 344 | { |
297c5eee | 345 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; |
1da177e4 LT |
346 | struct rb_node **rb_link, *rb_parent; |
347 | int retval; | |
348 | unsigned long charge; | |
349 | struct mempolicy *pol; | |
350 | ||
351 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 352 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
353 | /* |
354 | * Not linked in yet - no deadlock potential: | |
355 | */ | |
356 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 357 | |
1da177e4 LT |
358 | mm->locked_vm = 0; |
359 | mm->mmap = NULL; | |
360 | mm->mmap_cache = NULL; | |
361 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 362 | mm->cached_hole_size = ~0UL; |
1da177e4 | 363 | mm->map_count = 0; |
94894244 | 364 | cpumask_clear(mm_cpumask(mm)); |
1da177e4 LT |
365 | mm->mm_rb = RB_ROOT; |
366 | rb_link = &mm->mm_rb.rb_node; | |
367 | rb_parent = NULL; | |
368 | pprev = &mm->mmap; | |
f8af4da3 | 369 | retval = ksm_fork(mm, oldmm); |
ba76149f AA |
370 | if (retval) |
371 | goto out; | |
372 | retval = khugepaged_fork(mm, oldmm); | |
f8af4da3 HD |
373 | if (retval) |
374 | goto out; | |
1da177e4 | 375 | |
297c5eee | 376 | prev = NULL; |
fd3e42fc | 377 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
378 | struct file *file; |
379 | ||
380 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
381 | long pages = vma_pages(mpnt); |
382 | mm->total_vm -= pages; | |
ab50b8ed | 383 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 384 | -pages); |
1da177e4 LT |
385 | continue; |
386 | } | |
387 | charge = 0; | |
388 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
7edc8b0a SP |
389 | unsigned long len; |
390 | len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
191c5424 | 391 | if (security_vm_enough_memory_mm(oldmm, len)) /* sic */ |
1da177e4 LT |
392 | goto fail_nomem; |
393 | charge = len; | |
394 | } | |
e94b1766 | 395 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
396 | if (!tmp) |
397 | goto fail_nomem; | |
398 | *tmp = *mpnt; | |
5beb4930 | 399 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
846a16bf | 400 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
401 | retval = PTR_ERR(pol); |
402 | if (IS_ERR(pol)) | |
403 | goto fail_nomem_policy; | |
404 | vma_set_policy(tmp, pol); | |
a247c3a9 | 405 | tmp->vm_mm = mm; |
5beb4930 RR |
406 | if (anon_vma_fork(tmp, mpnt)) |
407 | goto fail_nomem_anon_vma_fork; | |
1da177e4 | 408 | tmp->vm_flags &= ~VM_LOCKED; |
297c5eee | 409 | tmp->vm_next = tmp->vm_prev = NULL; |
1da177e4 LT |
410 | file = tmp->vm_file; |
411 | if (file) { | |
f3a43f3f | 412 | struct inode *inode = file->f_path.dentry->d_inode; |
b88ed205 HD |
413 | struct address_space *mapping = file->f_mapping; |
414 | ||
1da177e4 LT |
415 | get_file(file); |
416 | if (tmp->vm_flags & VM_DENYWRITE) | |
417 | atomic_dec(&inode->i_writecount); | |
3d48ae45 | 418 | mutex_lock(&mapping->i_mmap_mutex); |
b88ed205 HD |
419 | if (tmp->vm_flags & VM_SHARED) |
420 | mapping->i_mmap_writable++; | |
b88ed205 HD |
421 | flush_dcache_mmap_lock(mapping); |
422 | /* insert tmp into the share list, just after mpnt */ | |
1da177e4 | 423 | vma_prio_tree_add(tmp, mpnt); |
b88ed205 | 424 | flush_dcache_mmap_unlock(mapping); |
3d48ae45 | 425 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
426 | } |
427 | ||
a1e78772 MG |
428 | /* |
429 | * Clear hugetlb-related page reserves for children. This only | |
430 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
431 | * are not guaranteed to succeed, even if read-only | |
432 | */ | |
433 | if (is_vm_hugetlb_page(tmp)) | |
434 | reset_vma_resv_huge_pages(tmp); | |
435 | ||
1da177e4 | 436 | /* |
7ee78232 | 437 | * Link in the new vma and copy the page table entries. |
1da177e4 | 438 | */ |
1da177e4 LT |
439 | *pprev = tmp; |
440 | pprev = &tmp->vm_next; | |
297c5eee LT |
441 | tmp->vm_prev = prev; |
442 | prev = tmp; | |
1da177e4 LT |
443 | |
444 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
445 | rb_link = &tmp->vm_rb.rb_right; | |
446 | rb_parent = &tmp->vm_rb; | |
447 | ||
448 | mm->map_count++; | |
0b0db14c | 449 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
450 | |
451 | if (tmp->vm_ops && tmp->vm_ops->open) | |
452 | tmp->vm_ops->open(tmp); | |
453 | ||
454 | if (retval) | |
455 | goto out; | |
682968e0 SD |
456 | |
457 | if (file && uprobe_mmap(tmp)) | |
458 | goto out; | |
1da177e4 | 459 | } |
d6dd61c8 JF |
460 | /* a new mm has just been created */ |
461 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 462 | retval = 0; |
1da177e4 | 463 | out: |
7ee78232 | 464 | up_write(&mm->mmap_sem); |
fd3e42fc | 465 | flush_tlb_mm(oldmm); |
1da177e4 LT |
466 | up_write(&oldmm->mmap_sem); |
467 | return retval; | |
5beb4930 RR |
468 | fail_nomem_anon_vma_fork: |
469 | mpol_put(pol); | |
1da177e4 LT |
470 | fail_nomem_policy: |
471 | kmem_cache_free(vm_area_cachep, tmp); | |
472 | fail_nomem: | |
473 | retval = -ENOMEM; | |
474 | vm_unacct_memory(charge); | |
475 | goto out; | |
476 | } | |
477 | ||
fb0a685c | 478 | static inline int mm_alloc_pgd(struct mm_struct *mm) |
1da177e4 LT |
479 | { |
480 | mm->pgd = pgd_alloc(mm); | |
481 | if (unlikely(!mm->pgd)) | |
482 | return -ENOMEM; | |
483 | return 0; | |
484 | } | |
485 | ||
fb0a685c | 486 | static inline void mm_free_pgd(struct mm_struct *mm) |
1da177e4 | 487 | { |
5e541973 | 488 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
489 | } |
490 | #else | |
491 | #define dup_mmap(mm, oldmm) (0) | |
492 | #define mm_alloc_pgd(mm) (0) | |
493 | #define mm_free_pgd(mm) | |
494 | #endif /* CONFIG_MMU */ | |
495 | ||
23ff4440 | 496 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 497 | |
e94b1766 | 498 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
499 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
500 | ||
4cb0e11b HK |
501 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
502 | ||
503 | static int __init coredump_filter_setup(char *s) | |
504 | { | |
505 | default_dump_filter = | |
506 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
507 | MMF_DUMP_FILTER_MASK; | |
508 | return 1; | |
509 | } | |
510 | ||
511 | __setup("coredump_filter=", coredump_filter_setup); | |
512 | ||
1da177e4 LT |
513 | #include <linux/init_task.h> |
514 | ||
858f0993 AD |
515 | static void mm_init_aio(struct mm_struct *mm) |
516 | { | |
517 | #ifdef CONFIG_AIO | |
518 | spin_lock_init(&mm->ioctx_lock); | |
519 | INIT_HLIST_HEAD(&mm->ioctx_list); | |
520 | #endif | |
521 | } | |
522 | ||
fb0a685c | 523 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) |
1da177e4 LT |
524 | { |
525 | atomic_set(&mm->mm_users, 1); | |
526 | atomic_set(&mm->mm_count, 1); | |
527 | init_rwsem(&mm->mmap_sem); | |
528 | INIT_LIST_HEAD(&mm->mmlist); | |
f8af4da3 HD |
529 | mm->flags = (current->mm) ? |
530 | (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; | |
999d9fc1 | 531 | mm->core_state = NULL; |
1da177e4 | 532 | mm->nr_ptes = 0; |
d559db08 | 533 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 534 | spin_lock_init(&mm->page_table_lock); |
1da177e4 | 535 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 536 | mm->cached_hole_size = ~0UL; |
858f0993 | 537 | mm_init_aio(mm); |
cf475ad2 | 538 | mm_init_owner(mm, p); |
1da177e4 LT |
539 | |
540 | if (likely(!mm_alloc_pgd(mm))) { | |
541 | mm->def_flags = 0; | |
cddb8a5c | 542 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
543 | return mm; |
544 | } | |
78fb7466 | 545 | |
1da177e4 LT |
546 | free_mm(mm); |
547 | return NULL; | |
548 | } | |
549 | ||
c3f0327f KK |
550 | static void check_mm(struct mm_struct *mm) |
551 | { | |
552 | int i; | |
553 | ||
554 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
555 | long x = atomic_long_read(&mm->rss_stat.count[i]); | |
556 | ||
557 | if (unlikely(x)) | |
558 | printk(KERN_ALERT "BUG: Bad rss-counter state " | |
559 | "mm:%p idx:%d val:%ld\n", mm, i, x); | |
560 | } | |
561 | ||
562 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
563 | VM_BUG_ON(mm->pmd_huge_pte); | |
564 | #endif | |
565 | } | |
566 | ||
1da177e4 LT |
567 | /* |
568 | * Allocate and initialize an mm_struct. | |
569 | */ | |
fb0a685c | 570 | struct mm_struct *mm_alloc(void) |
1da177e4 | 571 | { |
fb0a685c | 572 | struct mm_struct *mm; |
1da177e4 LT |
573 | |
574 | mm = allocate_mm(); | |
de03c72c KM |
575 | if (!mm) |
576 | return NULL; | |
577 | ||
578 | memset(mm, 0, sizeof(*mm)); | |
6345d24d LT |
579 | mm_init_cpumask(mm); |
580 | return mm_init(mm, current); | |
1da177e4 LT |
581 | } |
582 | ||
583 | /* | |
584 | * Called when the last reference to the mm | |
585 | * is dropped: either by a lazy thread or by | |
586 | * mmput. Free the page directory and the mm. | |
587 | */ | |
7ad5b3a5 | 588 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
589 | { |
590 | BUG_ON(mm == &init_mm); | |
591 | mm_free_pgd(mm); | |
592 | destroy_context(mm); | |
cddb8a5c | 593 | mmu_notifier_mm_destroy(mm); |
c3f0327f | 594 | check_mm(mm); |
1da177e4 LT |
595 | free_mm(mm); |
596 | } | |
6d4e4c4f | 597 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
598 | |
599 | /* | |
600 | * Decrement the use count and release all resources for an mm. | |
601 | */ | |
602 | void mmput(struct mm_struct *mm) | |
603 | { | |
0ae26f1b AM |
604 | might_sleep(); |
605 | ||
1da177e4 | 606 | if (atomic_dec_and_test(&mm->mm_users)) { |
d4b3b638 | 607 | uprobe_clear_state(mm); |
1da177e4 | 608 | exit_aio(mm); |
1c2fb7a4 | 609 | ksm_exit(mm); |
ba76149f | 610 | khugepaged_exit(mm); /* must run before exit_mmap */ |
1da177e4 | 611 | exit_mmap(mm); |
925d1c40 | 612 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
613 | if (!list_empty(&mm->mmlist)) { |
614 | spin_lock(&mmlist_lock); | |
615 | list_del(&mm->mmlist); | |
616 | spin_unlock(&mmlist_lock); | |
617 | } | |
801460d0 HS |
618 | if (mm->binfmt) |
619 | module_put(mm->binfmt->module); | |
1da177e4 LT |
620 | mmdrop(mm); |
621 | } | |
622 | } | |
623 | EXPORT_SYMBOL_GPL(mmput); | |
624 | ||
38646013 JS |
625 | /* |
626 | * We added or removed a vma mapping the executable. The vmas are only mapped | |
627 | * during exec and are not mapped with the mmap system call. | |
628 | * Callers must hold down_write() on the mm's mmap_sem for these | |
629 | */ | |
630 | void added_exe_file_vma(struct mm_struct *mm) | |
631 | { | |
632 | mm->num_exe_file_vmas++; | |
633 | } | |
634 | ||
635 | void removed_exe_file_vma(struct mm_struct *mm) | |
636 | { | |
637 | mm->num_exe_file_vmas--; | |
fb0a685c | 638 | if ((mm->num_exe_file_vmas == 0) && mm->exe_file) { |
38646013 JS |
639 | fput(mm->exe_file); |
640 | mm->exe_file = NULL; | |
641 | } | |
642 | ||
643 | } | |
644 | ||
645 | void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file) | |
646 | { | |
647 | if (new_exe_file) | |
648 | get_file(new_exe_file); | |
649 | if (mm->exe_file) | |
650 | fput(mm->exe_file); | |
651 | mm->exe_file = new_exe_file; | |
652 | mm->num_exe_file_vmas = 0; | |
653 | } | |
654 | ||
655 | struct file *get_mm_exe_file(struct mm_struct *mm) | |
656 | { | |
657 | struct file *exe_file; | |
658 | ||
659 | /* We need mmap_sem to protect against races with removal of | |
660 | * VM_EXECUTABLE vmas */ | |
661 | down_read(&mm->mmap_sem); | |
662 | exe_file = mm->exe_file; | |
663 | if (exe_file) | |
664 | get_file(exe_file); | |
665 | up_read(&mm->mmap_sem); | |
666 | return exe_file; | |
667 | } | |
668 | ||
669 | static void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm) | |
670 | { | |
671 | /* It's safe to write the exe_file pointer without exe_file_lock because | |
672 | * this is called during fork when the task is not yet in /proc */ | |
673 | newmm->exe_file = get_mm_exe_file(oldmm); | |
674 | } | |
675 | ||
1da177e4 LT |
676 | /** |
677 | * get_task_mm - acquire a reference to the task's mm | |
678 | * | |
246bb0b1 | 679 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
680 | * this kernel workthread has transiently adopted a user mm with use_mm, |
681 | * to do its AIO) is not set and if so returns a reference to it, after | |
682 | * bumping up the use count. User must release the mm via mmput() | |
683 | * after use. Typically used by /proc and ptrace. | |
684 | */ | |
685 | struct mm_struct *get_task_mm(struct task_struct *task) | |
686 | { | |
687 | struct mm_struct *mm; | |
688 | ||
689 | task_lock(task); | |
690 | mm = task->mm; | |
691 | if (mm) { | |
246bb0b1 | 692 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
693 | mm = NULL; |
694 | else | |
695 | atomic_inc(&mm->mm_users); | |
696 | } | |
697 | task_unlock(task); | |
698 | return mm; | |
699 | } | |
700 | EXPORT_SYMBOL_GPL(get_task_mm); | |
701 | ||
8cdb878d CY |
702 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) |
703 | { | |
704 | struct mm_struct *mm; | |
705 | int err; | |
706 | ||
707 | err = mutex_lock_killable(&task->signal->cred_guard_mutex); | |
708 | if (err) | |
709 | return ERR_PTR(err); | |
710 | ||
711 | mm = get_task_mm(task); | |
712 | if (mm && mm != current->mm && | |
713 | !ptrace_may_access(task, mode)) { | |
714 | mmput(mm); | |
715 | mm = ERR_PTR(-EACCES); | |
716 | } | |
717 | mutex_unlock(&task->signal->cred_guard_mutex); | |
718 | ||
719 | return mm; | |
720 | } | |
721 | ||
57b59c4a | 722 | static void complete_vfork_done(struct task_struct *tsk) |
c415c3b4 | 723 | { |
d68b46fe | 724 | struct completion *vfork; |
c415c3b4 | 725 | |
d68b46fe ON |
726 | task_lock(tsk); |
727 | vfork = tsk->vfork_done; | |
728 | if (likely(vfork)) { | |
729 | tsk->vfork_done = NULL; | |
730 | complete(vfork); | |
731 | } | |
732 | task_unlock(tsk); | |
733 | } | |
734 | ||
735 | static int wait_for_vfork_done(struct task_struct *child, | |
736 | struct completion *vfork) | |
737 | { | |
738 | int killed; | |
739 | ||
740 | freezer_do_not_count(); | |
741 | killed = wait_for_completion_killable(vfork); | |
742 | freezer_count(); | |
743 | ||
744 | if (killed) { | |
745 | task_lock(child); | |
746 | child->vfork_done = NULL; | |
747 | task_unlock(child); | |
748 | } | |
749 | ||
750 | put_task_struct(child); | |
751 | return killed; | |
c415c3b4 ON |
752 | } |
753 | ||
1da177e4 LT |
754 | /* Please note the differences between mmput and mm_release. |
755 | * mmput is called whenever we stop holding onto a mm_struct, | |
756 | * error success whatever. | |
757 | * | |
758 | * mm_release is called after a mm_struct has been removed | |
759 | * from the current process. | |
760 | * | |
761 | * This difference is important for error handling, when we | |
762 | * only half set up a mm_struct for a new process and need to restore | |
763 | * the old one. Because we mmput the new mm_struct before | |
764 | * restoring the old one. . . | |
765 | * Eric Biederman 10 January 1998 | |
766 | */ | |
767 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
768 | { | |
8141c7f3 LT |
769 | /* Get rid of any futexes when releasing the mm */ |
770 | #ifdef CONFIG_FUTEX | |
fc6b177d | 771 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 772 | exit_robust_list(tsk); |
fc6b177d PZ |
773 | tsk->robust_list = NULL; |
774 | } | |
8141c7f3 | 775 | #ifdef CONFIG_COMPAT |
fc6b177d | 776 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 777 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
778 | tsk->compat_robust_list = NULL; |
779 | } | |
8141c7f3 | 780 | #endif |
322a2c10 TG |
781 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
782 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
783 | #endif |
784 | ||
0326f5a9 SD |
785 | uprobe_free_utask(tsk); |
786 | ||
1da177e4 LT |
787 | /* Get rid of any cached register state */ |
788 | deactivate_mm(tsk, mm); | |
789 | ||
fec1d011 RM |
790 | /* |
791 | * If we're exiting normally, clear a user-space tid field if | |
792 | * requested. We leave this alone when dying by signal, to leave | |
793 | * the value intact in a core dump, and to save the unnecessary | |
d68b46fe ON |
794 | * trouble, say, a killed vfork parent shouldn't touch this mm. |
795 | * Userland only wants this done for a sys_exit. | |
fec1d011 | 796 | */ |
9c8a8228 ED |
797 | if (tsk->clear_child_tid) { |
798 | if (!(tsk->flags & PF_SIGNALED) && | |
799 | atomic_read(&mm->mm_users) > 1) { | |
800 | /* | |
801 | * We don't check the error code - if userspace has | |
802 | * not set up a proper pointer then tough luck. | |
803 | */ | |
804 | put_user(0, tsk->clear_child_tid); | |
805 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
806 | 1, NULL, NULL, 0); | |
807 | } | |
1da177e4 | 808 | tsk->clear_child_tid = NULL; |
1da177e4 | 809 | } |
f7505d64 KK |
810 | |
811 | /* | |
812 | * All done, finally we can wake up parent and return this mm to him. | |
813 | * Also kthread_stop() uses this completion for synchronization. | |
814 | */ | |
815 | if (tsk->vfork_done) | |
816 | complete_vfork_done(tsk); | |
1da177e4 LT |
817 | } |
818 | ||
a0a7ec30 JD |
819 | /* |
820 | * Allocate a new mm structure and copy contents from the | |
821 | * mm structure of the passed in task structure. | |
822 | */ | |
402b0862 | 823 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
824 | { |
825 | struct mm_struct *mm, *oldmm = current->mm; | |
826 | int err; | |
827 | ||
828 | if (!oldmm) | |
829 | return NULL; | |
830 | ||
831 | mm = allocate_mm(); | |
832 | if (!mm) | |
833 | goto fail_nomem; | |
834 | ||
835 | memcpy(mm, oldmm, sizeof(*mm)); | |
6345d24d | 836 | mm_init_cpumask(mm); |
a0a7ec30 | 837 | |
e7a00c45 AA |
838 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
839 | mm->pmd_huge_pte = NULL; | |
840 | #endif | |
d4b3b638 | 841 | uprobe_reset_state(mm); |
e7a00c45 | 842 | |
78fb7466 | 843 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
844 | goto fail_nomem; |
845 | ||
846 | if (init_new_context(tsk, mm)) | |
847 | goto fail_nocontext; | |
848 | ||
925d1c40 MH |
849 | dup_mm_exe_file(oldmm, mm); |
850 | ||
a0a7ec30 JD |
851 | err = dup_mmap(mm, oldmm); |
852 | if (err) | |
853 | goto free_pt; | |
854 | ||
855 | mm->hiwater_rss = get_mm_rss(mm); | |
856 | mm->hiwater_vm = mm->total_vm; | |
857 | ||
801460d0 HS |
858 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
859 | goto free_pt; | |
860 | ||
a0a7ec30 JD |
861 | return mm; |
862 | ||
863 | free_pt: | |
801460d0 HS |
864 | /* don't put binfmt in mmput, we haven't got module yet */ |
865 | mm->binfmt = NULL; | |
a0a7ec30 JD |
866 | mmput(mm); |
867 | ||
868 | fail_nomem: | |
869 | return NULL; | |
870 | ||
871 | fail_nocontext: | |
872 | /* | |
873 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
874 | * because it calls destroy_context() | |
875 | */ | |
876 | mm_free_pgd(mm); | |
877 | free_mm(mm); | |
878 | return NULL; | |
879 | } | |
880 | ||
fb0a685c | 881 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 882 | { |
fb0a685c | 883 | struct mm_struct *mm, *oldmm; |
1da177e4 LT |
884 | int retval; |
885 | ||
886 | tsk->min_flt = tsk->maj_flt = 0; | |
887 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
888 | #ifdef CONFIG_DETECT_HUNG_TASK |
889 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
890 | #endif | |
1da177e4 LT |
891 | |
892 | tsk->mm = NULL; | |
893 | tsk->active_mm = NULL; | |
894 | ||
895 | /* | |
896 | * Are we cloning a kernel thread? | |
897 | * | |
898 | * We need to steal a active VM for that.. | |
899 | */ | |
900 | oldmm = current->mm; | |
901 | if (!oldmm) | |
902 | return 0; | |
903 | ||
904 | if (clone_flags & CLONE_VM) { | |
905 | atomic_inc(&oldmm->mm_users); | |
906 | mm = oldmm; | |
1da177e4 LT |
907 | goto good_mm; |
908 | } | |
909 | ||
910 | retval = -ENOMEM; | |
a0a7ec30 | 911 | mm = dup_mm(tsk); |
1da177e4 LT |
912 | if (!mm) |
913 | goto fail_nomem; | |
914 | ||
1da177e4 LT |
915 | good_mm: |
916 | tsk->mm = mm; | |
917 | tsk->active_mm = mm; | |
918 | return 0; | |
919 | ||
1da177e4 LT |
920 | fail_nomem: |
921 | return retval; | |
1da177e4 LT |
922 | } |
923 | ||
a39bc516 | 924 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 925 | { |
498052bb | 926 | struct fs_struct *fs = current->fs; |
1da177e4 | 927 | if (clone_flags & CLONE_FS) { |
498052bb | 928 | /* tsk->fs is already what we want */ |
2a4419b5 | 929 | spin_lock(&fs->lock); |
498052bb | 930 | if (fs->in_exec) { |
2a4419b5 | 931 | spin_unlock(&fs->lock); |
498052bb AV |
932 | return -EAGAIN; |
933 | } | |
934 | fs->users++; | |
2a4419b5 | 935 | spin_unlock(&fs->lock); |
1da177e4 LT |
936 | return 0; |
937 | } | |
498052bb | 938 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
939 | if (!tsk->fs) |
940 | return -ENOMEM; | |
941 | return 0; | |
942 | } | |
943 | ||
fb0a685c | 944 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk) |
a016f338 JD |
945 | { |
946 | struct files_struct *oldf, *newf; | |
947 | int error = 0; | |
948 | ||
949 | /* | |
950 | * A background process may not have any files ... | |
951 | */ | |
952 | oldf = current->files; | |
953 | if (!oldf) | |
954 | goto out; | |
955 | ||
956 | if (clone_flags & CLONE_FILES) { | |
957 | atomic_inc(&oldf->count); | |
958 | goto out; | |
959 | } | |
960 | ||
a016f338 JD |
961 | newf = dup_fd(oldf, &error); |
962 | if (!newf) | |
963 | goto out; | |
964 | ||
965 | tsk->files = newf; | |
966 | error = 0; | |
967 | out: | |
968 | return error; | |
969 | } | |
970 | ||
fadad878 | 971 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
972 | { |
973 | #ifdef CONFIG_BLOCK | |
974 | struct io_context *ioc = current->io_context; | |
6e736be7 | 975 | struct io_context *new_ioc; |
fd0928df JA |
976 | |
977 | if (!ioc) | |
978 | return 0; | |
fadad878 JA |
979 | /* |
980 | * Share io context with parent, if CLONE_IO is set | |
981 | */ | |
982 | if (clone_flags & CLONE_IO) { | |
3d48749d TH |
983 | ioc_task_link(ioc); |
984 | tsk->io_context = ioc; | |
fadad878 | 985 | } else if (ioprio_valid(ioc->ioprio)) { |
6e736be7 TH |
986 | new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE); |
987 | if (unlikely(!new_ioc)) | |
fd0928df JA |
988 | return -ENOMEM; |
989 | ||
6e736be7 | 990 | new_ioc->ioprio = ioc->ioprio; |
11a3122f | 991 | put_io_context(new_ioc); |
fd0928df JA |
992 | } |
993 | #endif | |
994 | return 0; | |
995 | } | |
996 | ||
a39bc516 | 997 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
998 | { |
999 | struct sighand_struct *sig; | |
1000 | ||
60348802 | 1001 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
1002 | atomic_inc(¤t->sighand->count); |
1003 | return 0; | |
1004 | } | |
1005 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 1006 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
1007 | if (!sig) |
1008 | return -ENOMEM; | |
1da177e4 LT |
1009 | atomic_set(&sig->count, 1); |
1010 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
1011 | return 0; | |
1012 | } | |
1013 | ||
a7e5328a | 1014 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 1015 | { |
d80e731e ON |
1016 | if (atomic_dec_and_test(&sighand->count)) { |
1017 | signalfd_cleanup(sighand); | |
c81addc9 | 1018 | kmem_cache_free(sighand_cachep, sighand); |
d80e731e | 1019 | } |
c81addc9 ON |
1020 | } |
1021 | ||
f06febc9 FM |
1022 | |
1023 | /* | |
1024 | * Initialize POSIX timer handling for a thread group. | |
1025 | */ | |
1026 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
1027 | { | |
78d7d407 JS |
1028 | unsigned long cpu_limit; |
1029 | ||
f06febc9 FM |
1030 | /* Thread group counters. */ |
1031 | thread_group_cputime_init(sig); | |
1032 | ||
78d7d407 JS |
1033 | cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
1034 | if (cpu_limit != RLIM_INFINITY) { | |
1035 | sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit); | |
6279a751 ON |
1036 | sig->cputimer.running = 1; |
1037 | } | |
1038 | ||
f06febc9 FM |
1039 | /* The timer lists. */ |
1040 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
1041 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
1042 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
1043 | } | |
1044 | ||
a39bc516 | 1045 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
1046 | { |
1047 | struct signal_struct *sig; | |
1da177e4 | 1048 | |
4ab6c083 | 1049 | if (clone_flags & CLONE_THREAD) |
490dea45 | 1050 | return 0; |
490dea45 | 1051 | |
a56704ef | 1052 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
1053 | tsk->signal = sig; |
1054 | if (!sig) | |
1055 | return -ENOMEM; | |
1056 | ||
b3ac022c | 1057 | sig->nr_threads = 1; |
1da177e4 | 1058 | atomic_set(&sig->live, 1); |
b3ac022c | 1059 | atomic_set(&sig->sigcnt, 1); |
1da177e4 | 1060 | init_waitqueue_head(&sig->wait_chldexit); |
b3bfa0cb SB |
1061 | if (clone_flags & CLONE_NEWPID) |
1062 | sig->flags |= SIGNAL_UNKILLABLE; | |
db51aecc | 1063 | sig->curr_target = tsk; |
1da177e4 LT |
1064 | init_sigpending(&sig->shared_pending); |
1065 | INIT_LIST_HEAD(&sig->posix_timers); | |
1066 | ||
c9cb2e3d | 1067 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 1068 | sig->real_timer.function = it_real_fn; |
1da177e4 | 1069 | |
1da177e4 LT |
1070 | task_lock(current->group_leader); |
1071 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
1072 | task_unlock(current->group_leader); | |
1073 | ||
6279a751 ON |
1074 | posix_cpu_timers_init_group(sig); |
1075 | ||
522ed776 | 1076 | tty_audit_fork(sig); |
5091faa4 | 1077 | sched_autogroup_fork(sig); |
522ed776 | 1078 | |
4714d1d3 | 1079 | #ifdef CONFIG_CGROUPS |
257058ae | 1080 | init_rwsem(&sig->group_rwsem); |
4714d1d3 BB |
1081 | #endif |
1082 | ||
28b83c51 | 1083 | sig->oom_adj = current->signal->oom_adj; |
a63d83f4 | 1084 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 1085 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 1086 | |
ebec18a6 LP |
1087 | sig->has_child_subreaper = current->signal->has_child_subreaper || |
1088 | current->signal->is_child_subreaper; | |
1089 | ||
9b1bf12d KM |
1090 | mutex_init(&sig->cred_guard_mutex); |
1091 | ||
1da177e4 LT |
1092 | return 0; |
1093 | } | |
1094 | ||
a39bc516 | 1095 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
1096 | { |
1097 | unsigned long new_flags = p->flags; | |
1098 | ||
21aa9af0 | 1099 | new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER); |
1da177e4 | 1100 | new_flags |= PF_FORKNOEXEC; |
1da177e4 LT |
1101 | p->flags = new_flags; |
1102 | } | |
1103 | ||
17da2bd9 | 1104 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
1105 | { |
1106 | current->clear_child_tid = tidptr; | |
1107 | ||
b488893a | 1108 | return task_pid_vnr(current); |
1da177e4 LT |
1109 | } |
1110 | ||
a39bc516 | 1111 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 1112 | { |
1d615482 | 1113 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 1114 | #ifdef CONFIG_RT_MUTEXES |
732375c6 | 1115 | plist_head_init(&p->pi_waiters); |
23f78d4a | 1116 | p->pi_blocked_on = NULL; |
23f78d4a IM |
1117 | #endif |
1118 | } | |
1119 | ||
cf475ad2 BS |
1120 | #ifdef CONFIG_MM_OWNER |
1121 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
1122 | { | |
1123 | mm->owner = p; | |
1124 | } | |
1125 | #endif /* CONFIG_MM_OWNER */ | |
1126 | ||
f06febc9 FM |
1127 | /* |
1128 | * Initialize POSIX timer handling for a single task. | |
1129 | */ | |
1130 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
1131 | { | |
64861634 MS |
1132 | tsk->cputime_expires.prof_exp = 0; |
1133 | tsk->cputime_expires.virt_exp = 0; | |
f06febc9 FM |
1134 | tsk->cputime_expires.sched_exp = 0; |
1135 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
1136 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
1137 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
1138 | } | |
1139 | ||
1da177e4 LT |
1140 | /* |
1141 | * This creates a new process as a copy of the old one, | |
1142 | * but does not actually start it yet. | |
1143 | * | |
1144 | * It copies the registers, and all the appropriate | |
1145 | * parts of the process environment (as per the clone | |
1146 | * flags). The actual kick-off is left to the caller. | |
1147 | */ | |
36c8b586 IM |
1148 | static struct task_struct *copy_process(unsigned long clone_flags, |
1149 | unsigned long stack_start, | |
1150 | struct pt_regs *regs, | |
1151 | unsigned long stack_size, | |
36c8b586 | 1152 | int __user *child_tidptr, |
09a05394 RM |
1153 | struct pid *pid, |
1154 | int trace) | |
1da177e4 LT |
1155 | { |
1156 | int retval; | |
a24efe62 | 1157 | struct task_struct *p; |
b4f48b63 | 1158 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
1159 | |
1160 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
1161 | return ERR_PTR(-EINVAL); | |
1162 | ||
1163 | /* | |
1164 | * Thread groups must share signals as well, and detached threads | |
1165 | * can only be started up within the thread group. | |
1166 | */ | |
1167 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1168 | return ERR_PTR(-EINVAL); | |
1169 | ||
1170 | /* | |
1171 | * Shared signal handlers imply shared VM. By way of the above, | |
1172 | * thread groups also imply shared VM. Blocking this case allows | |
1173 | * for various simplifications in other code. | |
1174 | */ | |
1175 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1176 | return ERR_PTR(-EINVAL); | |
1177 | ||
123be07b SB |
1178 | /* |
1179 | * Siblings of global init remain as zombies on exit since they are | |
1180 | * not reaped by their parent (swapper). To solve this and to avoid | |
1181 | * multi-rooted process trees, prevent global and container-inits | |
1182 | * from creating siblings. | |
1183 | */ | |
1184 | if ((clone_flags & CLONE_PARENT) && | |
1185 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1186 | return ERR_PTR(-EINVAL); | |
1187 | ||
1da177e4 LT |
1188 | retval = security_task_create(clone_flags); |
1189 | if (retval) | |
1190 | goto fork_out; | |
1191 | ||
1192 | retval = -ENOMEM; | |
1193 | p = dup_task_struct(current); | |
1194 | if (!p) | |
1195 | goto fork_out; | |
1196 | ||
f7e8b616 | 1197 | ftrace_graph_init_task(p); |
e2cfabdf | 1198 | get_seccomp_filter(p); |
f7e8b616 | 1199 | |
bea493a0 PZ |
1200 | rt_mutex_init_task(p); |
1201 | ||
d12c1a37 | 1202 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1203 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1204 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1205 | #endif | |
1da177e4 | 1206 | retval = -EAGAIN; |
3b11a1de | 1207 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1208 | task_rlimit(p, RLIMIT_NPROC)) { |
1da177e4 | 1209 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && |
18b6e041 | 1210 | p->real_cred->user != INIT_USER) |
1da177e4 LT |
1211 | goto bad_fork_free; |
1212 | } | |
72fa5997 | 1213 | current->flags &= ~PF_NPROC_EXCEEDED; |
1da177e4 | 1214 | |
f1752eec DH |
1215 | retval = copy_creds(p, clone_flags); |
1216 | if (retval < 0) | |
1217 | goto bad_fork_free; | |
1da177e4 LT |
1218 | |
1219 | /* | |
1220 | * If multiple threads are within copy_process(), then this check | |
1221 | * triggers too late. This doesn't hurt, the check is only there | |
1222 | * to stop root fork bombs. | |
1223 | */ | |
04ec93fe | 1224 | retval = -EAGAIN; |
1da177e4 LT |
1225 | if (nr_threads >= max_threads) |
1226 | goto bad_fork_cleanup_count; | |
1227 | ||
a1261f54 | 1228 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1229 | goto bad_fork_cleanup_count; |
1230 | ||
1da177e4 | 1231 | p->did_exec = 0; |
ca74e92b | 1232 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1233 | copy_flags(clone_flags, p); |
1da177e4 LT |
1234 | INIT_LIST_HEAD(&p->children); |
1235 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1236 | rcu_copy_process(p); |
1da177e4 LT |
1237 | p->vfork_done = NULL; |
1238 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1239 | |
1da177e4 LT |
1240 | init_sigpending(&p->pending); |
1241 | ||
64861634 MS |
1242 | p->utime = p->stime = p->gtime = 0; |
1243 | p->utimescaled = p->stimescaled = 0; | |
d99ca3b9 | 1244 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
64861634 | 1245 | p->prev_utime = p->prev_stime = 0; |
d99ca3b9 | 1246 | #endif |
a3a2e76c KH |
1247 | #if defined(SPLIT_RSS_COUNTING) |
1248 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1249 | #endif | |
172ba844 | 1250 | |
6976675d AV |
1251 | p->default_timer_slack_ns = current->timer_slack_ns; |
1252 | ||
5995477a | 1253 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1254 | acct_clear_integrals(p); |
1255 | ||
f06febc9 | 1256 | posix_cpu_timers_init(p); |
1da177e4 | 1257 | |
1da177e4 | 1258 | do_posix_clock_monotonic_gettime(&p->start_time); |
924b42d5 TJ |
1259 | p->real_start_time = p->start_time; |
1260 | monotonic_to_bootbased(&p->real_start_time); | |
1da177e4 | 1261 | p->io_context = NULL; |
1da177e4 | 1262 | p->audit_context = NULL; |
4714d1d3 | 1263 | if (clone_flags & CLONE_THREAD) |
257058ae | 1264 | threadgroup_change_begin(current); |
b4f48b63 | 1265 | cgroup_fork(p); |
1da177e4 | 1266 | #ifdef CONFIG_NUMA |
846a16bf | 1267 | p->mempolicy = mpol_dup(p->mempolicy); |
fb0a685c DRO |
1268 | if (IS_ERR(p->mempolicy)) { |
1269 | retval = PTR_ERR(p->mempolicy); | |
1270 | p->mempolicy = NULL; | |
1271 | goto bad_fork_cleanup_cgroup; | |
1272 | } | |
c61afb18 | 1273 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1274 | #endif |
778d3b0f MH |
1275 | #ifdef CONFIG_CPUSETS |
1276 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE; | |
1277 | p->cpuset_slab_spread_rotor = NUMA_NO_NODE; | |
cc9a6c87 | 1278 | seqcount_init(&p->mems_allowed_seq); |
778d3b0f | 1279 | #endif |
de30a2b3 IM |
1280 | #ifdef CONFIG_TRACE_IRQFLAGS |
1281 | p->irq_events = 0; | |
b36e4758 RK |
1282 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1283 | p->hardirqs_enabled = 1; | |
1284 | #else | |
de30a2b3 | 1285 | p->hardirqs_enabled = 0; |
b36e4758 | 1286 | #endif |
de30a2b3 IM |
1287 | p->hardirq_enable_ip = 0; |
1288 | p->hardirq_enable_event = 0; | |
1289 | p->hardirq_disable_ip = _THIS_IP_; | |
1290 | p->hardirq_disable_event = 0; | |
1291 | p->softirqs_enabled = 1; | |
1292 | p->softirq_enable_ip = _THIS_IP_; | |
1293 | p->softirq_enable_event = 0; | |
1294 | p->softirq_disable_ip = 0; | |
1295 | p->softirq_disable_event = 0; | |
1296 | p->hardirq_context = 0; | |
1297 | p->softirq_context = 0; | |
1298 | #endif | |
fbb9ce95 IM |
1299 | #ifdef CONFIG_LOCKDEP |
1300 | p->lockdep_depth = 0; /* no locks held yet */ | |
1301 | p->curr_chain_key = 0; | |
1302 | p->lockdep_recursion = 0; | |
1303 | #endif | |
1da177e4 | 1304 | |
408894ee IM |
1305 | #ifdef CONFIG_DEBUG_MUTEXES |
1306 | p->blocked_on = NULL; /* not blocked yet */ | |
1307 | #endif | |
569b846d KH |
1308 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
1309 | p->memcg_batch.do_batch = 0; | |
1310 | p->memcg_batch.memcg = NULL; | |
1311 | #endif | |
0f481406 | 1312 | |
3c90e6e9 | 1313 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
3e51e3ed | 1314 | sched_fork(p); |
6ab423e0 | 1315 | |
cdd6c482 | 1316 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1317 | if (retval) |
1318 | goto bad_fork_cleanup_policy; | |
fb0a685c DRO |
1319 | retval = audit_alloc(p); |
1320 | if (retval) | |
f1752eec | 1321 | goto bad_fork_cleanup_policy; |
1da177e4 | 1322 | /* copy all the process information */ |
fb0a685c DRO |
1323 | retval = copy_semundo(clone_flags, p); |
1324 | if (retval) | |
1da177e4 | 1325 | goto bad_fork_cleanup_audit; |
fb0a685c DRO |
1326 | retval = copy_files(clone_flags, p); |
1327 | if (retval) | |
1da177e4 | 1328 | goto bad_fork_cleanup_semundo; |
fb0a685c DRO |
1329 | retval = copy_fs(clone_flags, p); |
1330 | if (retval) | |
1da177e4 | 1331 | goto bad_fork_cleanup_files; |
fb0a685c DRO |
1332 | retval = copy_sighand(clone_flags, p); |
1333 | if (retval) | |
1da177e4 | 1334 | goto bad_fork_cleanup_fs; |
fb0a685c DRO |
1335 | retval = copy_signal(clone_flags, p); |
1336 | if (retval) | |
1da177e4 | 1337 | goto bad_fork_cleanup_sighand; |
fb0a685c DRO |
1338 | retval = copy_mm(clone_flags, p); |
1339 | if (retval) | |
1da177e4 | 1340 | goto bad_fork_cleanup_signal; |
fb0a685c DRO |
1341 | retval = copy_namespaces(clone_flags, p); |
1342 | if (retval) | |
d84f4f99 | 1343 | goto bad_fork_cleanup_mm; |
fb0a685c DRO |
1344 | retval = copy_io(clone_flags, p); |
1345 | if (retval) | |
fd0928df | 1346 | goto bad_fork_cleanup_namespaces; |
6f2c55b8 | 1347 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
1da177e4 | 1348 | if (retval) |
fd0928df | 1349 | goto bad_fork_cleanup_io; |
1da177e4 | 1350 | |
425fb2b4 PE |
1351 | if (pid != &init_struct_pid) { |
1352 | retval = -ENOMEM; | |
61bce0f1 | 1353 | pid = alloc_pid(p->nsproxy->pid_ns); |
425fb2b4 | 1354 | if (!pid) |
fd0928df | 1355 | goto bad_fork_cleanup_io; |
425fb2b4 PE |
1356 | } |
1357 | ||
1358 | p->pid = pid_nr(pid); | |
1359 | p->tgid = p->pid; | |
1360 | if (clone_flags & CLONE_THREAD) | |
1361 | p->tgid = current->tgid; | |
1362 | ||
1da177e4 LT |
1363 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1364 | /* | |
1365 | * Clear TID on mm_release()? | |
1366 | */ | |
fb0a685c | 1367 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL; |
73c10101 JA |
1368 | #ifdef CONFIG_BLOCK |
1369 | p->plug = NULL; | |
1370 | #endif | |
42b2dd0a | 1371 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1372 | p->robust_list = NULL; |
1373 | #ifdef CONFIG_COMPAT | |
1374 | p->compat_robust_list = NULL; | |
1375 | #endif | |
c87e2837 IM |
1376 | INIT_LIST_HEAD(&p->pi_state_list); |
1377 | p->pi_state_cache = NULL; | |
42b2dd0a | 1378 | #endif |
0326f5a9 | 1379 | uprobe_copy_process(p); |
f9a3879a GM |
1380 | /* |
1381 | * sigaltstack should be cleared when sharing the same VM | |
1382 | */ | |
1383 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1384 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1385 | ||
1da177e4 | 1386 | /* |
6580807d ON |
1387 | * Syscall tracing and stepping should be turned off in the |
1388 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1389 | */ |
6580807d | 1390 | user_disable_single_step(p); |
1da177e4 | 1391 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1392 | #ifdef TIF_SYSCALL_EMU |
1393 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1394 | #endif | |
9745512c | 1395 | clear_all_latency_tracing(p); |
1da177e4 | 1396 | |
1da177e4 | 1397 | /* ok, now we should be set up.. */ |
5f8aadd8 ON |
1398 | if (clone_flags & CLONE_THREAD) |
1399 | p->exit_signal = -1; | |
1400 | else if (clone_flags & CLONE_PARENT) | |
1401 | p->exit_signal = current->group_leader->exit_signal; | |
1402 | else | |
1403 | p->exit_signal = (clone_flags & CSIGNAL); | |
1404 | ||
1da177e4 LT |
1405 | p->pdeath_signal = 0; |
1406 | p->exit_state = 0; | |
1407 | ||
9d823e8f WF |
1408 | p->nr_dirtied = 0; |
1409 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10); | |
83712358 | 1410 | p->dirty_paused_when = 0; |
9d823e8f | 1411 | |
1da177e4 LT |
1412 | /* |
1413 | * Ok, make it visible to the rest of the system. | |
1414 | * We dont wake it up yet. | |
1415 | */ | |
1416 | p->group_leader = p; | |
47e65328 | 1417 | INIT_LIST_HEAD(&p->thread_group); |
e73f8959 | 1418 | INIT_HLIST_HEAD(&p->task_works); |
1da177e4 | 1419 | |
b4f48b63 PM |
1420 | /* Now that the task is set up, run cgroup callbacks if |
1421 | * necessary. We need to run them before the task is visible | |
1422 | * on the tasklist. */ | |
1423 | cgroup_fork_callbacks(p); | |
1424 | cgroup_callbacks_done = 1; | |
1425 | ||
1da177e4 LT |
1426 | /* Need tasklist lock for parent etc handling! */ |
1427 | write_lock_irq(&tasklist_lock); | |
1428 | ||
1da177e4 | 1429 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1430 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1431 | p->real_parent = current->real_parent; |
2d5516cb ON |
1432 | p->parent_exec_id = current->parent_exec_id; |
1433 | } else { | |
1da177e4 | 1434 | p->real_parent = current; |
2d5516cb ON |
1435 | p->parent_exec_id = current->self_exec_id; |
1436 | } | |
1da177e4 | 1437 | |
3f17da69 | 1438 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1439 | |
1440 | /* | |
1441 | * Process group and session signals need to be delivered to just the | |
1442 | * parent before the fork or both the parent and the child after the | |
1443 | * fork. Restart if a signal comes in before we add the new process to | |
1444 | * it's process group. | |
1445 | * A fatal signal pending means that current will exit, so the new | |
1446 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
fb0a685c | 1447 | */ |
23ff4440 | 1448 | recalc_sigpending(); |
4a2c7a78 ON |
1449 | if (signal_pending(current)) { |
1450 | spin_unlock(¤t->sighand->siglock); | |
1451 | write_unlock_irq(&tasklist_lock); | |
1452 | retval = -ERESTARTNOINTR; | |
f7e8b616 | 1453 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1454 | } |
1455 | ||
1da177e4 | 1456 | if (clone_flags & CLONE_THREAD) { |
b3ac022c | 1457 | current->signal->nr_threads++; |
4ab6c083 | 1458 | atomic_inc(¤t->signal->live); |
b3ac022c | 1459 | atomic_inc(¤t->signal->sigcnt); |
1da177e4 | 1460 | p->group_leader = current->group_leader; |
47e65328 | 1461 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 LT |
1462 | } |
1463 | ||
73b9ebfe | 1464 | if (likely(p->pid)) { |
4b9d33e6 | 1465 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); |
73b9ebfe ON |
1466 | |
1467 | if (thread_group_leader(p)) { | |
45a68628 | 1468 | if (is_child_reaper(pid)) |
30e49c26 | 1469 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1470 | |
fea9d175 | 1471 | p->signal->leader_pid = pid; |
9c9f4ded | 1472 | p->signal->tty = tty_kref_get(current->signal->tty); |
5cd17569 EB |
1473 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1474 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
9cd80bbb | 1475 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 1476 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
909ea964 | 1477 | __this_cpu_inc(process_counts); |
73b9ebfe | 1478 | } |
85868995 | 1479 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1480 | nr_threads++; |
1da177e4 LT |
1481 | } |
1482 | ||
1da177e4 | 1483 | total_forks++; |
3f17da69 | 1484 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1485 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1486 | proc_fork_connector(p); |
817929ec | 1487 | cgroup_post_fork(p); |
4714d1d3 | 1488 | if (clone_flags & CLONE_THREAD) |
257058ae | 1489 | threadgroup_change_end(current); |
cdd6c482 | 1490 | perf_event_fork(p); |
43d2b113 KH |
1491 | |
1492 | trace_task_newtask(p, clone_flags); | |
1493 | ||
1da177e4 LT |
1494 | return p; |
1495 | ||
425fb2b4 PE |
1496 | bad_fork_free_pid: |
1497 | if (pid != &init_struct_pid) | |
1498 | free_pid(pid); | |
fd0928df | 1499 | bad_fork_cleanup_io: |
b69f2292 LR |
1500 | if (p->io_context) |
1501 | exit_io_context(p); | |
ab516013 | 1502 | bad_fork_cleanup_namespaces: |
5e2bf014 MG |
1503 | if (unlikely(clone_flags & CLONE_NEWPID)) |
1504 | pid_ns_release_proc(p->nsproxy->pid_ns); | |
444f378b | 1505 | exit_task_namespaces(p); |
1da177e4 | 1506 | bad_fork_cleanup_mm: |
c9f01245 | 1507 | if (p->mm) |
1da177e4 LT |
1508 | mmput(p->mm); |
1509 | bad_fork_cleanup_signal: | |
4ab6c083 | 1510 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 1511 | free_signal_struct(p->signal); |
1da177e4 | 1512 | bad_fork_cleanup_sighand: |
a7e5328a | 1513 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1514 | bad_fork_cleanup_fs: |
1515 | exit_fs(p); /* blocking */ | |
1516 | bad_fork_cleanup_files: | |
1517 | exit_files(p); /* blocking */ | |
1518 | bad_fork_cleanup_semundo: | |
1519 | exit_sem(p); | |
1520 | bad_fork_cleanup_audit: | |
1521 | audit_free(p); | |
1da177e4 | 1522 | bad_fork_cleanup_policy: |
cdd6c482 | 1523 | perf_event_free_task(p); |
1da177e4 | 1524 | #ifdef CONFIG_NUMA |
f0be3d32 | 1525 | mpol_put(p->mempolicy); |
b4f48b63 | 1526 | bad_fork_cleanup_cgroup: |
1da177e4 | 1527 | #endif |
4714d1d3 | 1528 | if (clone_flags & CLONE_THREAD) |
257058ae | 1529 | threadgroup_change_end(current); |
b4f48b63 | 1530 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1531 | delayacct_tsk_free(p); |
a1261f54 | 1532 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 | 1533 | bad_fork_cleanup_count: |
d84f4f99 | 1534 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1535 | exit_creds(p); |
1da177e4 LT |
1536 | bad_fork_free: |
1537 | free_task(p); | |
fe7d37d1 ON |
1538 | fork_out: |
1539 | return ERR_PTR(retval); | |
1da177e4 LT |
1540 | } |
1541 | ||
6b2fb3c6 | 1542 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1543 | { |
1544 | memset(regs, 0, sizeof(struct pt_regs)); | |
1545 | return regs; | |
1546 | } | |
1547 | ||
f106eee1 ON |
1548 | static inline void init_idle_pids(struct pid_link *links) |
1549 | { | |
1550 | enum pid_type type; | |
1551 | ||
1552 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
1553 | INIT_HLIST_NODE(&links[type].node); /* not really needed */ | |
1554 | links[type].pid = &init_struct_pid; | |
1555 | } | |
1556 | } | |
1557 | ||
9abcf40b | 1558 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1559 | { |
36c8b586 | 1560 | struct task_struct *task; |
1da177e4 LT |
1561 | struct pt_regs regs; |
1562 | ||
30e49c26 | 1563 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1564 | &init_struct_pid, 0); |
f106eee1 ON |
1565 | if (!IS_ERR(task)) { |
1566 | init_idle_pids(task->pids); | |
753ca4f3 | 1567 | init_idle(task, cpu); |
f106eee1 | 1568 | } |
73b9ebfe | 1569 | |
1da177e4 LT |
1570 | return task; |
1571 | } | |
1572 | ||
1da177e4 LT |
1573 | /* |
1574 | * Ok, this is the main fork-routine. | |
1575 | * | |
1576 | * It copies the process, and if successful kick-starts | |
1577 | * it and waits for it to finish using the VM if required. | |
1578 | */ | |
1579 | long do_fork(unsigned long clone_flags, | |
1580 | unsigned long stack_start, | |
1581 | struct pt_regs *regs, | |
1582 | unsigned long stack_size, | |
1583 | int __user *parent_tidptr, | |
1584 | int __user *child_tidptr) | |
1585 | { | |
1586 | struct task_struct *p; | |
1587 | int trace = 0; | |
92476d7f | 1588 | long nr; |
1da177e4 | 1589 | |
18b6e041 SH |
1590 | /* |
1591 | * Do some preliminary argument and permissions checking before we | |
1592 | * actually start allocating stuff | |
1593 | */ | |
1594 | if (clone_flags & CLONE_NEWUSER) { | |
1595 | if (clone_flags & CLONE_THREAD) | |
1596 | return -EINVAL; | |
1597 | /* hopefully this check will go away when userns support is | |
1598 | * complete | |
1599 | */ | |
7657d904 SH |
1600 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
1601 | !capable(CAP_SETGID)) | |
18b6e041 SH |
1602 | return -EPERM; |
1603 | } | |
1604 | ||
09a05394 | 1605 | /* |
4b9d33e6 TH |
1606 | * Determine whether and which event to report to ptracer. When |
1607 | * called from kernel_thread or CLONE_UNTRACED is explicitly | |
1608 | * requested, no event is reported; otherwise, report if the event | |
1609 | * for the type of forking is enabled. | |
09a05394 | 1610 | */ |
4b9d33e6 TH |
1611 | if (likely(user_mode(regs)) && !(clone_flags & CLONE_UNTRACED)) { |
1612 | if (clone_flags & CLONE_VFORK) | |
1613 | trace = PTRACE_EVENT_VFORK; | |
1614 | else if ((clone_flags & CSIGNAL) != SIGCHLD) | |
1615 | trace = PTRACE_EVENT_CLONE; | |
1616 | else | |
1617 | trace = PTRACE_EVENT_FORK; | |
1618 | ||
1619 | if (likely(!ptrace_event_enabled(current, trace))) | |
1620 | trace = 0; | |
1621 | } | |
1da177e4 | 1622 | |
a6f5e063 | 1623 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1624 | child_tidptr, NULL, trace); |
1da177e4 LT |
1625 | /* |
1626 | * Do this prior waking up the new thread - the thread pointer | |
1627 | * might get invalid after that point, if the thread exits quickly. | |
1628 | */ | |
1629 | if (!IS_ERR(p)) { | |
1630 | struct completion vfork; | |
1631 | ||
0a16b607 MD |
1632 | trace_sched_process_fork(current, p); |
1633 | ||
6c5f3e7b | 1634 | nr = task_pid_vnr(p); |
30e49c26 PE |
1635 | |
1636 | if (clone_flags & CLONE_PARENT_SETTID) | |
1637 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1638 | |
1da177e4 LT |
1639 | if (clone_flags & CLONE_VFORK) { |
1640 | p->vfork_done = &vfork; | |
1641 | init_completion(&vfork); | |
d68b46fe | 1642 | get_task_struct(p); |
1da177e4 LT |
1643 | } |
1644 | ||
3e51e3ed | 1645 | wake_up_new_task(p); |
1da177e4 | 1646 | |
4b9d33e6 TH |
1647 | /* forking complete and child started to run, tell ptracer */ |
1648 | if (unlikely(trace)) | |
1649 | ptrace_event(trace, nr); | |
09a05394 | 1650 | |
1da177e4 | 1651 | if (clone_flags & CLONE_VFORK) { |
d68b46fe ON |
1652 | if (!wait_for_vfork_done(p, &vfork)) |
1653 | ptrace_event(PTRACE_EVENT_VFORK_DONE, nr); | |
1da177e4 LT |
1654 | } |
1655 | } else { | |
92476d7f | 1656 | nr = PTR_ERR(p); |
1da177e4 | 1657 | } |
92476d7f | 1658 | return nr; |
1da177e4 LT |
1659 | } |
1660 | ||
5fd63b30 RT |
1661 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1662 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1663 | #endif | |
1664 | ||
51cc5068 | 1665 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1666 | { |
1667 | struct sighand_struct *sighand = data; | |
1668 | ||
a35afb83 | 1669 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1670 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1671 | } |
1672 | ||
1da177e4 LT |
1673 | void __init proc_caches_init(void) |
1674 | { | |
1675 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1676 | sizeof(struct sighand_struct), 0, | |
2dff4405 VN |
1677 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
1678 | SLAB_NOTRACK, sighand_ctor); | |
1da177e4 LT |
1679 | signal_cachep = kmem_cache_create("signal_cache", |
1680 | sizeof(struct signal_struct), 0, | |
2dff4405 | 1681 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1682 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 1683 | sizeof(struct files_struct), 0, |
2dff4405 | 1684 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1685 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 1686 | sizeof(struct fs_struct), 0, |
2dff4405 | 1687 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
6345d24d LT |
1688 | /* |
1689 | * FIXME! The "sizeof(struct mm_struct)" currently includes the | |
1690 | * whole struct cpumask for the OFFSTACK case. We could change | |
1691 | * this to *only* allocate as much of it as required by the | |
1692 | * maximum number of CPU's we can ever have. The cpumask_allocation | |
1693 | * is at the end of the structure, exactly for that reason. | |
1694 | */ | |
1da177e4 | 1695 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1696 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
2dff4405 | 1697 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
33e5d769 | 1698 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
8feae131 | 1699 | mmap_init(); |
66577193 | 1700 | nsproxy_cache_init(); |
1da177e4 | 1701 | } |
cf2e340f | 1702 | |
cf2e340f | 1703 | /* |
9bfb23fc | 1704 | * Check constraints on flags passed to the unshare system call. |
cf2e340f | 1705 | */ |
9bfb23fc | 1706 | static int check_unshare_flags(unsigned long unshare_flags) |
cf2e340f | 1707 | { |
9bfb23fc ON |
1708 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
1709 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| | |
1710 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) | |
1711 | return -EINVAL; | |
cf2e340f | 1712 | /* |
9bfb23fc ON |
1713 | * Not implemented, but pretend it works if there is nothing to |
1714 | * unshare. Note that unsharing CLONE_THREAD or CLONE_SIGHAND | |
1715 | * needs to unshare vm. | |
cf2e340f | 1716 | */ |
9bfb23fc ON |
1717 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { |
1718 | /* FIXME: get_task_mm() increments ->mm_users */ | |
1719 | if (atomic_read(¤t->mm->mm_users) > 1) | |
1720 | return -EINVAL; | |
1721 | } | |
cf2e340f JD |
1722 | |
1723 | return 0; | |
1724 | } | |
1725 | ||
1726 | /* | |
99d1419d | 1727 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1728 | */ |
1729 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1730 | { | |
1731 | struct fs_struct *fs = current->fs; | |
1732 | ||
498052bb AV |
1733 | if (!(unshare_flags & CLONE_FS) || !fs) |
1734 | return 0; | |
1735 | ||
1736 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1737 | if (fs->users == 1) | |
1738 | return 0; | |
1739 | ||
1740 | *new_fsp = copy_fs_struct(fs); | |
1741 | if (!*new_fsp) | |
1742 | return -ENOMEM; | |
cf2e340f JD |
1743 | |
1744 | return 0; | |
1745 | } | |
1746 | ||
cf2e340f | 1747 | /* |
a016f338 | 1748 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1749 | */ |
1750 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1751 | { | |
1752 | struct files_struct *fd = current->files; | |
a016f338 | 1753 | int error = 0; |
cf2e340f JD |
1754 | |
1755 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1756 | (fd && atomic_read(&fd->count) > 1)) { |
1757 | *new_fdp = dup_fd(fd, &error); | |
1758 | if (!*new_fdp) | |
1759 | return error; | |
1760 | } | |
cf2e340f JD |
1761 | |
1762 | return 0; | |
1763 | } | |
1764 | ||
cf2e340f JD |
1765 | /* |
1766 | * unshare allows a process to 'unshare' part of the process | |
1767 | * context which was originally shared using clone. copy_* | |
1768 | * functions used by do_fork() cannot be used here directly | |
1769 | * because they modify an inactive task_struct that is being | |
1770 | * constructed. Here we are modifying the current, active, | |
1771 | * task_struct. | |
1772 | */ | |
6559eed8 | 1773 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f | 1774 | { |
cf2e340f | 1775 | struct fs_struct *fs, *new_fs = NULL; |
cf2e340f | 1776 | struct files_struct *fd, *new_fd = NULL; |
cf7b708c | 1777 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1778 | int do_sysvsem = 0; |
9bfb23fc | 1779 | int err; |
cf2e340f | 1780 | |
9bfb23fc ON |
1781 | err = check_unshare_flags(unshare_flags); |
1782 | if (err) | |
06f9d4f9 EB |
1783 | goto bad_unshare_out; |
1784 | ||
9bfb23fc ON |
1785 | /* |
1786 | * If unsharing namespace, must also unshare filesystem information. | |
1787 | */ | |
1788 | if (unshare_flags & CLONE_NEWNS) | |
1789 | unshare_flags |= CLONE_FS; | |
6013f67f MS |
1790 | /* |
1791 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1792 | * to a new ipc namespace, the semaphore arrays from the old | |
1793 | * namespace are unreachable. | |
1794 | */ | |
1795 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1796 | do_sysvsem = 1; |
fb0a685c DRO |
1797 | err = unshare_fs(unshare_flags, &new_fs); |
1798 | if (err) | |
9bfb23fc | 1799 | goto bad_unshare_out; |
fb0a685c DRO |
1800 | err = unshare_fd(unshare_flags, &new_fd); |
1801 | if (err) | |
9bfb23fc | 1802 | goto bad_unshare_cleanup_fs; |
fb0a685c DRO |
1803 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, new_fs); |
1804 | if (err) | |
9edff4ab | 1805 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1806 | |
9bfb23fc | 1807 | if (new_fs || new_fd || do_sysvsem || new_nsproxy) { |
9edff4ab MS |
1808 | if (do_sysvsem) { |
1809 | /* | |
1810 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1811 | */ | |
1812 | exit_sem(current); | |
1813 | } | |
ab516013 | 1814 | |
c0b2fc31 | 1815 | if (new_nsproxy) { |
cf7b708c PE |
1816 | switch_task_namespaces(current, new_nsproxy); |
1817 | new_nsproxy = NULL; | |
c0b2fc31 | 1818 | } |
cf2e340f | 1819 | |
cf7b708c PE |
1820 | task_lock(current); |
1821 | ||
cf2e340f JD |
1822 | if (new_fs) { |
1823 | fs = current->fs; | |
2a4419b5 | 1824 | spin_lock(&fs->lock); |
cf2e340f | 1825 | current->fs = new_fs; |
498052bb AV |
1826 | if (--fs->users) |
1827 | new_fs = NULL; | |
1828 | else | |
1829 | new_fs = fs; | |
2a4419b5 | 1830 | spin_unlock(&fs->lock); |
cf2e340f JD |
1831 | } |
1832 | ||
cf2e340f JD |
1833 | if (new_fd) { |
1834 | fd = current->files; | |
1835 | current->files = new_fd; | |
1836 | new_fd = fd; | |
1837 | } | |
1838 | ||
1839 | task_unlock(current); | |
1840 | } | |
1841 | ||
c0b2fc31 | 1842 | if (new_nsproxy) |
444f378b | 1843 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1844 | |
cf2e340f JD |
1845 | bad_unshare_cleanup_fd: |
1846 | if (new_fd) | |
1847 | put_files_struct(new_fd); | |
1848 | ||
cf2e340f JD |
1849 | bad_unshare_cleanup_fs: |
1850 | if (new_fs) | |
498052bb | 1851 | free_fs_struct(new_fs); |
cf2e340f | 1852 | |
cf2e340f JD |
1853 | bad_unshare_out: |
1854 | return err; | |
1855 | } | |
3b125388 AV |
1856 | |
1857 | /* | |
1858 | * Helper to unshare the files of the current task. | |
1859 | * We don't want to expose copy_files internals to | |
1860 | * the exec layer of the kernel. | |
1861 | */ | |
1862 | ||
1863 | int unshare_files(struct files_struct **displaced) | |
1864 | { | |
1865 | struct task_struct *task = current; | |
50704516 | 1866 | struct files_struct *copy = NULL; |
3b125388 AV |
1867 | int error; |
1868 | ||
1869 | error = unshare_fd(CLONE_FILES, ©); | |
1870 | if (error || !copy) { | |
1871 | *displaced = NULL; | |
1872 | return error; | |
1873 | } | |
1874 | *displaced = task->files; | |
1875 | task_lock(task); | |
1876 | task->files = copy; | |
1877 | task_unlock(task); | |
1878 | return 0; | |
1879 | } |