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> |
1da177e4 LT |
37 | #include <linux/swap.h> |
38 | #include <linux/syscalls.h> | |
39 | #include <linux/jiffies.h> | |
09a05394 | 40 | #include <linux/tracehook.h> |
1da177e4 | 41 | #include <linux/futex.h> |
8141c7f3 | 42 | #include <linux/compat.h> |
7c3ab738 | 43 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 44 | #include <linux/rcupdate.h> |
1da177e4 LT |
45 | #include <linux/ptrace.h> |
46 | #include <linux/mount.h> | |
47 | #include <linux/audit.h> | |
78fb7466 | 48 | #include <linux/memcontrol.h> |
f201ae23 | 49 | #include <linux/ftrace.h> |
1da177e4 LT |
50 | #include <linux/profile.h> |
51 | #include <linux/rmap.h> | |
f8af4da3 | 52 | #include <linux/ksm.h> |
1da177e4 | 53 | #include <linux/acct.h> |
8f0ab514 | 54 | #include <linux/tsacct_kern.h> |
9f46080c | 55 | #include <linux/cn_proc.h> |
ba96a0c8 | 56 | #include <linux/freezer.h> |
ca74e92b | 57 | #include <linux/delayacct.h> |
ad4ecbcb | 58 | #include <linux/taskstats_kern.h> |
0a425405 | 59 | #include <linux/random.h> |
522ed776 | 60 | #include <linux/tty.h> |
6f4e6433 | 61 | #include <linux/proc_fs.h> |
fd0928df | 62 | #include <linux/blkdev.h> |
5ad4e53b | 63 | #include <linux/fs_struct.h> |
7c9f8861 | 64 | #include <linux/magic.h> |
cdd6c482 | 65 | #include <linux/perf_event.h> |
42c4ab41 | 66 | #include <linux/posix-timers.h> |
8e7cac79 | 67 | #include <linux/user-return-notifier.h> |
1da177e4 LT |
68 | |
69 | #include <asm/pgtable.h> | |
70 | #include <asm/pgalloc.h> | |
71 | #include <asm/uaccess.h> | |
72 | #include <asm/mmu_context.h> | |
73 | #include <asm/cacheflush.h> | |
74 | #include <asm/tlbflush.h> | |
75 | ||
ad8d75ff SR |
76 | #include <trace/events/sched.h> |
77 | ||
1da177e4 LT |
78 | /* |
79 | * Protected counters by write_lock_irq(&tasklist_lock) | |
80 | */ | |
81 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
82 | int nr_threads; /* The idle threads do not count.. */ | |
83 | ||
84 | int max_threads; /* tunable limit on nr_threads */ | |
85 | ||
86 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
87 | ||
c59923a1 | 88 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
89 | |
90 | #ifdef CONFIG_PROVE_RCU | |
91 | int lockdep_tasklist_lock_is_held(void) | |
92 | { | |
93 | return lockdep_is_held(&tasklist_lock); | |
94 | } | |
95 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
96 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
97 | |
98 | int nr_processes(void) | |
99 | { | |
100 | int cpu; | |
101 | int total = 0; | |
102 | ||
1d510750 | 103 | for_each_possible_cpu(cpu) |
1da177e4 LT |
104 | total += per_cpu(process_counts, cpu); |
105 | ||
106 | return total; | |
107 | } | |
108 | ||
109 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
110 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
111 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 112 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
113 | #endif |
114 | ||
b69c49b7 FT |
115 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
116 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
117 | { | |
118 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
119 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
120 | #else | |
121 | gfp_t mask = GFP_KERNEL; | |
122 | #endif | |
123 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
124 | } | |
125 | ||
126 | static inline void free_thread_info(struct thread_info *ti) | |
127 | { | |
128 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
129 | } | |
130 | #endif | |
131 | ||
1da177e4 | 132 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 133 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
134 | |
135 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 136 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
137 | |
138 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 139 | struct kmem_cache *files_cachep; |
1da177e4 LT |
140 | |
141 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 142 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
143 | |
144 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 145 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
146 | |
147 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 148 | static struct kmem_cache *mm_cachep; |
1da177e4 | 149 | |
c6a7f572 KM |
150 | static void account_kernel_stack(struct thread_info *ti, int account) |
151 | { | |
152 | struct zone *zone = page_zone(virt_to_page(ti)); | |
153 | ||
154 | mod_zone_page_state(zone, NR_KERNEL_STACK, account); | |
155 | } | |
156 | ||
1da177e4 LT |
157 | void free_task(struct task_struct *tsk) |
158 | { | |
3e26c149 | 159 | prop_local_destroy_single(&tsk->dirties); |
c6a7f572 | 160 | account_kernel_stack(tsk->stack, -1); |
f7e4217b | 161 | free_thread_info(tsk->stack); |
23f78d4a | 162 | rt_mutex_debug_task_free(tsk); |
fb52607a | 163 | ftrace_graph_exit_task(tsk); |
1da177e4 LT |
164 | free_task_struct(tsk); |
165 | } | |
166 | EXPORT_SYMBOL(free_task); | |
167 | ||
ea6d290c ON |
168 | static inline void free_signal_struct(struct signal_struct *sig) |
169 | { | |
ea6d290c ON |
170 | kmem_cache_free(signal_cachep, sig); |
171 | } | |
172 | ||
173 | static inline void put_signal_struct(struct signal_struct *sig) | |
174 | { | |
175 | if (atomic_dec_and_test(&sig->sigcnt)) | |
176 | free_signal_struct(sig); | |
177 | } | |
178 | ||
158d9ebd | 179 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 180 | { |
270f722d | 181 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
182 | WARN_ON(atomic_read(&tsk->usage)); |
183 | WARN_ON(tsk == current); | |
184 | ||
e0e81739 | 185 | exit_creds(tsk); |
35df17c5 | 186 | delayacct_tsk_free(tsk); |
ea6d290c | 187 | put_signal_struct(tsk->signal); |
1da177e4 LT |
188 | |
189 | if (!profile_handoff_task(tsk)) | |
190 | free_task(tsk); | |
191 | } | |
192 | ||
2adee9b3 SS |
193 | /* |
194 | * macro override instead of weak attribute alias, to workaround | |
195 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
196 | */ | |
197 | #ifndef arch_task_cache_init | |
198 | #define arch_task_cache_init() | |
199 | #endif | |
61c4628b | 200 | |
1da177e4 LT |
201 | void __init fork_init(unsigned long mempages) |
202 | { | |
203 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
204 | #ifndef ARCH_MIN_TASKALIGN | |
205 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
206 | #endif | |
207 | /* create a slab on which task_structs can be allocated */ | |
208 | task_struct_cachep = | |
209 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
2dff4405 | 210 | ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); |
1da177e4 LT |
211 | #endif |
212 | ||
61c4628b SS |
213 | /* do the arch specific task caches init */ |
214 | arch_task_cache_init(); | |
215 | ||
1da177e4 LT |
216 | /* |
217 | * The default maximum number of threads is set to a safe | |
218 | * value: the thread structures can take up at most half | |
219 | * of memory. | |
220 | */ | |
221 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
222 | ||
223 | /* | |
224 | * we need to allow at least 20 threads to boot a system | |
225 | */ | |
226 | if(max_threads < 20) | |
227 | max_threads = 20; | |
228 | ||
229 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
230 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
231 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
232 | init_task.signal->rlim[RLIMIT_NPROC]; | |
233 | } | |
234 | ||
61c4628b SS |
235 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
236 | struct task_struct *src) | |
237 | { | |
238 | *dst = *src; | |
239 | return 0; | |
240 | } | |
241 | ||
1da177e4 LT |
242 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
243 | { | |
244 | struct task_struct *tsk; | |
245 | struct thread_info *ti; | |
7c9f8861 ES |
246 | unsigned long *stackend; |
247 | ||
3e26c149 | 248 | int err; |
1da177e4 LT |
249 | |
250 | prepare_to_copy(orig); | |
251 | ||
252 | tsk = alloc_task_struct(); | |
253 | if (!tsk) | |
254 | return NULL; | |
255 | ||
256 | ti = alloc_thread_info(tsk); | |
257 | if (!ti) { | |
258 | free_task_struct(tsk); | |
259 | return NULL; | |
260 | } | |
261 | ||
61c4628b SS |
262 | err = arch_dup_task_struct(tsk, orig); |
263 | if (err) | |
264 | goto out; | |
265 | ||
f7e4217b | 266 | tsk->stack = ti; |
3e26c149 PZ |
267 | |
268 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
269 | if (err) |
270 | goto out; | |
3e26c149 | 271 | |
10ebffde | 272 | setup_thread_stack(tsk, orig); |
8e7cac79 | 273 | clear_user_return_notifier(tsk); |
7c9f8861 ES |
274 | stackend = end_of_stack(tsk); |
275 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1da177e4 | 276 | |
0a425405 AV |
277 | #ifdef CONFIG_CC_STACKPROTECTOR |
278 | tsk->stack_canary = get_random_int(); | |
279 | #endif | |
280 | ||
1da177e4 LT |
281 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
282 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 283 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 284 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 285 | tsk->btrace_seq = 0; |
6c5c9341 | 286 | #endif |
a0aa7f68 | 287 | tsk->splice_pipe = NULL; |
c6a7f572 KM |
288 | |
289 | account_kernel_stack(ti, 1); | |
290 | ||
1da177e4 | 291 | return tsk; |
61c4628b SS |
292 | |
293 | out: | |
294 | free_thread_info(ti); | |
295 | free_task_struct(tsk); | |
296 | return NULL; | |
1da177e4 LT |
297 | } |
298 | ||
299 | #ifdef CONFIG_MMU | |
a39bc516 | 300 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 301 | { |
fd3e42fc | 302 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
303 | struct rb_node **rb_link, *rb_parent; |
304 | int retval; | |
305 | unsigned long charge; | |
306 | struct mempolicy *pol; | |
307 | ||
308 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 309 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
310 | /* |
311 | * Not linked in yet - no deadlock potential: | |
312 | */ | |
313 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 314 | |
1da177e4 LT |
315 | mm->locked_vm = 0; |
316 | mm->mmap = NULL; | |
317 | mm->mmap_cache = NULL; | |
318 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 319 | mm->cached_hole_size = ~0UL; |
1da177e4 | 320 | mm->map_count = 0; |
94894244 | 321 | cpumask_clear(mm_cpumask(mm)); |
1da177e4 LT |
322 | mm->mm_rb = RB_ROOT; |
323 | rb_link = &mm->mm_rb.rb_node; | |
324 | rb_parent = NULL; | |
325 | pprev = &mm->mmap; | |
f8af4da3 HD |
326 | retval = ksm_fork(mm, oldmm); |
327 | if (retval) | |
328 | goto out; | |
1da177e4 | 329 | |
fd3e42fc | 330 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
331 | struct file *file; |
332 | ||
333 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
334 | long pages = vma_pages(mpnt); |
335 | mm->total_vm -= pages; | |
ab50b8ed | 336 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 337 | -pages); |
1da177e4 LT |
338 | continue; |
339 | } | |
340 | charge = 0; | |
341 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
342 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
343 | if (security_vm_enough_memory(len)) | |
344 | goto fail_nomem; | |
345 | charge = len; | |
346 | } | |
e94b1766 | 347 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
348 | if (!tmp) |
349 | goto fail_nomem; | |
350 | *tmp = *mpnt; | |
5beb4930 | 351 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
846a16bf | 352 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
353 | retval = PTR_ERR(pol); |
354 | if (IS_ERR(pol)) | |
355 | goto fail_nomem_policy; | |
356 | vma_set_policy(tmp, pol); | |
5beb4930 RR |
357 | if (anon_vma_fork(tmp, mpnt)) |
358 | goto fail_nomem_anon_vma_fork; | |
1da177e4 LT |
359 | tmp->vm_flags &= ~VM_LOCKED; |
360 | tmp->vm_mm = mm; | |
361 | tmp->vm_next = NULL; | |
1da177e4 LT |
362 | file = tmp->vm_file; |
363 | if (file) { | |
f3a43f3f | 364 | struct inode *inode = file->f_path.dentry->d_inode; |
b88ed205 HD |
365 | struct address_space *mapping = file->f_mapping; |
366 | ||
1da177e4 LT |
367 | get_file(file); |
368 | if (tmp->vm_flags & VM_DENYWRITE) | |
369 | atomic_dec(&inode->i_writecount); | |
b88ed205 HD |
370 | spin_lock(&mapping->i_mmap_lock); |
371 | if (tmp->vm_flags & VM_SHARED) | |
372 | mapping->i_mmap_writable++; | |
1da177e4 | 373 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
b88ed205 HD |
374 | flush_dcache_mmap_lock(mapping); |
375 | /* insert tmp into the share list, just after mpnt */ | |
1da177e4 | 376 | vma_prio_tree_add(tmp, mpnt); |
b88ed205 HD |
377 | flush_dcache_mmap_unlock(mapping); |
378 | spin_unlock(&mapping->i_mmap_lock); | |
1da177e4 LT |
379 | } |
380 | ||
a1e78772 MG |
381 | /* |
382 | * Clear hugetlb-related page reserves for children. This only | |
383 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
384 | * are not guaranteed to succeed, even if read-only | |
385 | */ | |
386 | if (is_vm_hugetlb_page(tmp)) | |
387 | reset_vma_resv_huge_pages(tmp); | |
388 | ||
1da177e4 | 389 | /* |
7ee78232 | 390 | * Link in the new vma and copy the page table entries. |
1da177e4 | 391 | */ |
1da177e4 LT |
392 | *pprev = tmp; |
393 | pprev = &tmp->vm_next; | |
394 | ||
395 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
396 | rb_link = &tmp->vm_rb.rb_right; | |
397 | rb_parent = &tmp->vm_rb; | |
398 | ||
399 | mm->map_count++; | |
0b0db14c | 400 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
401 | |
402 | if (tmp->vm_ops && tmp->vm_ops->open) | |
403 | tmp->vm_ops->open(tmp); | |
404 | ||
405 | if (retval) | |
406 | goto out; | |
407 | } | |
d6dd61c8 JF |
408 | /* a new mm has just been created */ |
409 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 410 | retval = 0; |
1da177e4 | 411 | out: |
7ee78232 | 412 | up_write(&mm->mmap_sem); |
fd3e42fc | 413 | flush_tlb_mm(oldmm); |
1da177e4 LT |
414 | up_write(&oldmm->mmap_sem); |
415 | return retval; | |
5beb4930 RR |
416 | fail_nomem_anon_vma_fork: |
417 | mpol_put(pol); | |
1da177e4 LT |
418 | fail_nomem_policy: |
419 | kmem_cache_free(vm_area_cachep, tmp); | |
420 | fail_nomem: | |
421 | retval = -ENOMEM; | |
422 | vm_unacct_memory(charge); | |
423 | goto out; | |
424 | } | |
425 | ||
426 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
427 | { | |
428 | mm->pgd = pgd_alloc(mm); | |
429 | if (unlikely(!mm->pgd)) | |
430 | return -ENOMEM; | |
431 | return 0; | |
432 | } | |
433 | ||
434 | static inline void mm_free_pgd(struct mm_struct * mm) | |
435 | { | |
5e541973 | 436 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
437 | } |
438 | #else | |
439 | #define dup_mmap(mm, oldmm) (0) | |
440 | #define mm_alloc_pgd(mm) (0) | |
441 | #define mm_free_pgd(mm) | |
442 | #endif /* CONFIG_MMU */ | |
443 | ||
23ff4440 | 444 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 445 | |
e94b1766 | 446 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
447 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
448 | ||
4cb0e11b HK |
449 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
450 | ||
451 | static int __init coredump_filter_setup(char *s) | |
452 | { | |
453 | default_dump_filter = | |
454 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
455 | MMF_DUMP_FILTER_MASK; | |
456 | return 1; | |
457 | } | |
458 | ||
459 | __setup("coredump_filter=", coredump_filter_setup); | |
460 | ||
1da177e4 LT |
461 | #include <linux/init_task.h> |
462 | ||
858f0993 AD |
463 | static void mm_init_aio(struct mm_struct *mm) |
464 | { | |
465 | #ifdef CONFIG_AIO | |
466 | spin_lock_init(&mm->ioctx_lock); | |
467 | INIT_HLIST_HEAD(&mm->ioctx_list); | |
468 | #endif | |
469 | } | |
470 | ||
78fb7466 | 471 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
472 | { |
473 | atomic_set(&mm->mm_users, 1); | |
474 | atomic_set(&mm->mm_count, 1); | |
475 | init_rwsem(&mm->mmap_sem); | |
476 | INIT_LIST_HEAD(&mm->mmlist); | |
f8af4da3 HD |
477 | mm->flags = (current->mm) ? |
478 | (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; | |
999d9fc1 | 479 | mm->core_state = NULL; |
1da177e4 | 480 | mm->nr_ptes = 0; |
d559db08 | 481 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 482 | spin_lock_init(&mm->page_table_lock); |
1da177e4 | 483 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 484 | mm->cached_hole_size = ~0UL; |
858f0993 | 485 | mm_init_aio(mm); |
cf475ad2 | 486 | mm_init_owner(mm, p); |
1da177e4 LT |
487 | |
488 | if (likely(!mm_alloc_pgd(mm))) { | |
489 | mm->def_flags = 0; | |
cddb8a5c | 490 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
491 | return mm; |
492 | } | |
78fb7466 | 493 | |
1da177e4 LT |
494 | free_mm(mm); |
495 | return NULL; | |
496 | } | |
497 | ||
498 | /* | |
499 | * Allocate and initialize an mm_struct. | |
500 | */ | |
501 | struct mm_struct * mm_alloc(void) | |
502 | { | |
503 | struct mm_struct * mm; | |
504 | ||
505 | mm = allocate_mm(); | |
506 | if (mm) { | |
507 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 508 | mm = mm_init(mm, current); |
1da177e4 LT |
509 | } |
510 | return mm; | |
511 | } | |
512 | ||
513 | /* | |
514 | * Called when the last reference to the mm | |
515 | * is dropped: either by a lazy thread or by | |
516 | * mmput. Free the page directory and the mm. | |
517 | */ | |
7ad5b3a5 | 518 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
519 | { |
520 | BUG_ON(mm == &init_mm); | |
521 | mm_free_pgd(mm); | |
522 | destroy_context(mm); | |
cddb8a5c | 523 | mmu_notifier_mm_destroy(mm); |
1da177e4 LT |
524 | free_mm(mm); |
525 | } | |
6d4e4c4f | 526 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
527 | |
528 | /* | |
529 | * Decrement the use count and release all resources for an mm. | |
530 | */ | |
531 | void mmput(struct mm_struct *mm) | |
532 | { | |
0ae26f1b AM |
533 | might_sleep(); |
534 | ||
1da177e4 LT |
535 | if (atomic_dec_and_test(&mm->mm_users)) { |
536 | exit_aio(mm); | |
1c2fb7a4 | 537 | ksm_exit(mm); |
1da177e4 | 538 | exit_mmap(mm); |
925d1c40 | 539 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
540 | if (!list_empty(&mm->mmlist)) { |
541 | spin_lock(&mmlist_lock); | |
542 | list_del(&mm->mmlist); | |
543 | spin_unlock(&mmlist_lock); | |
544 | } | |
545 | put_swap_token(mm); | |
801460d0 HS |
546 | if (mm->binfmt) |
547 | module_put(mm->binfmt->module); | |
1da177e4 LT |
548 | mmdrop(mm); |
549 | } | |
550 | } | |
551 | EXPORT_SYMBOL_GPL(mmput); | |
552 | ||
553 | /** | |
554 | * get_task_mm - acquire a reference to the task's mm | |
555 | * | |
246bb0b1 | 556 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
557 | * this kernel workthread has transiently adopted a user mm with use_mm, |
558 | * to do its AIO) is not set and if so returns a reference to it, after | |
559 | * bumping up the use count. User must release the mm via mmput() | |
560 | * after use. Typically used by /proc and ptrace. | |
561 | */ | |
562 | struct mm_struct *get_task_mm(struct task_struct *task) | |
563 | { | |
564 | struct mm_struct *mm; | |
565 | ||
566 | task_lock(task); | |
567 | mm = task->mm; | |
568 | if (mm) { | |
246bb0b1 | 569 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
570 | mm = NULL; |
571 | else | |
572 | atomic_inc(&mm->mm_users); | |
573 | } | |
574 | task_unlock(task); | |
575 | return mm; | |
576 | } | |
577 | EXPORT_SYMBOL_GPL(get_task_mm); | |
578 | ||
579 | /* Please note the differences between mmput and mm_release. | |
580 | * mmput is called whenever we stop holding onto a mm_struct, | |
581 | * error success whatever. | |
582 | * | |
583 | * mm_release is called after a mm_struct has been removed | |
584 | * from the current process. | |
585 | * | |
586 | * This difference is important for error handling, when we | |
587 | * only half set up a mm_struct for a new process and need to restore | |
588 | * the old one. Because we mmput the new mm_struct before | |
589 | * restoring the old one. . . | |
590 | * Eric Biederman 10 January 1998 | |
591 | */ | |
592 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
593 | { | |
594 | struct completion *vfork_done = tsk->vfork_done; | |
595 | ||
8141c7f3 LT |
596 | /* Get rid of any futexes when releasing the mm */ |
597 | #ifdef CONFIG_FUTEX | |
fc6b177d | 598 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 599 | exit_robust_list(tsk); |
fc6b177d PZ |
600 | tsk->robust_list = NULL; |
601 | } | |
8141c7f3 | 602 | #ifdef CONFIG_COMPAT |
fc6b177d | 603 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 604 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
605 | tsk->compat_robust_list = NULL; |
606 | } | |
8141c7f3 | 607 | #endif |
322a2c10 TG |
608 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
609 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
610 | #endif |
611 | ||
1da177e4 LT |
612 | /* Get rid of any cached register state */ |
613 | deactivate_mm(tsk, mm); | |
614 | ||
615 | /* notify parent sleeping on vfork() */ | |
616 | if (vfork_done) { | |
617 | tsk->vfork_done = NULL; | |
618 | complete(vfork_done); | |
619 | } | |
fec1d011 RM |
620 | |
621 | /* | |
622 | * If we're exiting normally, clear a user-space tid field if | |
623 | * requested. We leave this alone when dying by signal, to leave | |
624 | * the value intact in a core dump, and to save the unnecessary | |
625 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
626 | */ | |
9c8a8228 ED |
627 | if (tsk->clear_child_tid) { |
628 | if (!(tsk->flags & PF_SIGNALED) && | |
629 | atomic_read(&mm->mm_users) > 1) { | |
630 | /* | |
631 | * We don't check the error code - if userspace has | |
632 | * not set up a proper pointer then tough luck. | |
633 | */ | |
634 | put_user(0, tsk->clear_child_tid); | |
635 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
636 | 1, NULL, NULL, 0); | |
637 | } | |
1da177e4 | 638 | tsk->clear_child_tid = NULL; |
1da177e4 LT |
639 | } |
640 | } | |
641 | ||
a0a7ec30 JD |
642 | /* |
643 | * Allocate a new mm structure and copy contents from the | |
644 | * mm structure of the passed in task structure. | |
645 | */ | |
402b0862 | 646 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
647 | { |
648 | struct mm_struct *mm, *oldmm = current->mm; | |
649 | int err; | |
650 | ||
651 | if (!oldmm) | |
652 | return NULL; | |
653 | ||
654 | mm = allocate_mm(); | |
655 | if (!mm) | |
656 | goto fail_nomem; | |
657 | ||
658 | memcpy(mm, oldmm, sizeof(*mm)); | |
659 | ||
7602bdf2 AC |
660 | /* Initializing for Swap token stuff */ |
661 | mm->token_priority = 0; | |
662 | mm->last_interval = 0; | |
663 | ||
78fb7466 | 664 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
665 | goto fail_nomem; |
666 | ||
667 | if (init_new_context(tsk, mm)) | |
668 | goto fail_nocontext; | |
669 | ||
925d1c40 MH |
670 | dup_mm_exe_file(oldmm, mm); |
671 | ||
a0a7ec30 JD |
672 | err = dup_mmap(mm, oldmm); |
673 | if (err) | |
674 | goto free_pt; | |
675 | ||
676 | mm->hiwater_rss = get_mm_rss(mm); | |
677 | mm->hiwater_vm = mm->total_vm; | |
678 | ||
801460d0 HS |
679 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
680 | goto free_pt; | |
681 | ||
a0a7ec30 JD |
682 | return mm; |
683 | ||
684 | free_pt: | |
801460d0 HS |
685 | /* don't put binfmt in mmput, we haven't got module yet */ |
686 | mm->binfmt = NULL; | |
a0a7ec30 JD |
687 | mmput(mm); |
688 | ||
689 | fail_nomem: | |
690 | return NULL; | |
691 | ||
692 | fail_nocontext: | |
693 | /* | |
694 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
695 | * because it calls destroy_context() | |
696 | */ | |
697 | mm_free_pgd(mm); | |
698 | free_mm(mm); | |
699 | return NULL; | |
700 | } | |
701 | ||
1da177e4 LT |
702 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
703 | { | |
704 | struct mm_struct * mm, *oldmm; | |
705 | int retval; | |
706 | ||
707 | tsk->min_flt = tsk->maj_flt = 0; | |
708 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
709 | #ifdef CONFIG_DETECT_HUNG_TASK |
710 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
711 | #endif | |
1da177e4 LT |
712 | |
713 | tsk->mm = NULL; | |
714 | tsk->active_mm = NULL; | |
715 | ||
716 | /* | |
717 | * Are we cloning a kernel thread? | |
718 | * | |
719 | * We need to steal a active VM for that.. | |
720 | */ | |
721 | oldmm = current->mm; | |
722 | if (!oldmm) | |
723 | return 0; | |
724 | ||
725 | if (clone_flags & CLONE_VM) { | |
726 | atomic_inc(&oldmm->mm_users); | |
727 | mm = oldmm; | |
1da177e4 LT |
728 | goto good_mm; |
729 | } | |
730 | ||
731 | retval = -ENOMEM; | |
a0a7ec30 | 732 | mm = dup_mm(tsk); |
1da177e4 LT |
733 | if (!mm) |
734 | goto fail_nomem; | |
735 | ||
1da177e4 | 736 | good_mm: |
7602bdf2 AC |
737 | /* Initializing for Swap token stuff */ |
738 | mm->token_priority = 0; | |
739 | mm->last_interval = 0; | |
740 | ||
1da177e4 LT |
741 | tsk->mm = mm; |
742 | tsk->active_mm = mm; | |
743 | return 0; | |
744 | ||
1da177e4 LT |
745 | fail_nomem: |
746 | return retval; | |
1da177e4 LT |
747 | } |
748 | ||
a39bc516 | 749 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 750 | { |
498052bb | 751 | struct fs_struct *fs = current->fs; |
1da177e4 | 752 | if (clone_flags & CLONE_FS) { |
498052bb AV |
753 | /* tsk->fs is already what we want */ |
754 | write_lock(&fs->lock); | |
755 | if (fs->in_exec) { | |
756 | write_unlock(&fs->lock); | |
757 | return -EAGAIN; | |
758 | } | |
759 | fs->users++; | |
760 | write_unlock(&fs->lock); | |
1da177e4 LT |
761 | return 0; |
762 | } | |
498052bb | 763 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
764 | if (!tsk->fs) |
765 | return -ENOMEM; | |
766 | return 0; | |
767 | } | |
768 | ||
a016f338 JD |
769 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
770 | { | |
771 | struct files_struct *oldf, *newf; | |
772 | int error = 0; | |
773 | ||
774 | /* | |
775 | * A background process may not have any files ... | |
776 | */ | |
777 | oldf = current->files; | |
778 | if (!oldf) | |
779 | goto out; | |
780 | ||
781 | if (clone_flags & CLONE_FILES) { | |
782 | atomic_inc(&oldf->count); | |
783 | goto out; | |
784 | } | |
785 | ||
a016f338 JD |
786 | newf = dup_fd(oldf, &error); |
787 | if (!newf) | |
788 | goto out; | |
789 | ||
790 | tsk->files = newf; | |
791 | error = 0; | |
792 | out: | |
793 | return error; | |
794 | } | |
795 | ||
fadad878 | 796 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
797 | { |
798 | #ifdef CONFIG_BLOCK | |
799 | struct io_context *ioc = current->io_context; | |
800 | ||
801 | if (!ioc) | |
802 | return 0; | |
fadad878 JA |
803 | /* |
804 | * Share io context with parent, if CLONE_IO is set | |
805 | */ | |
806 | if (clone_flags & CLONE_IO) { | |
807 | tsk->io_context = ioc_task_link(ioc); | |
808 | if (unlikely(!tsk->io_context)) | |
809 | return -ENOMEM; | |
810 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
811 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
812 | if (unlikely(!tsk->io_context)) | |
813 | return -ENOMEM; | |
814 | ||
fd0928df JA |
815 | tsk->io_context->ioprio = ioc->ioprio; |
816 | } | |
817 | #endif | |
818 | return 0; | |
819 | } | |
820 | ||
a39bc516 | 821 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
822 | { |
823 | struct sighand_struct *sig; | |
824 | ||
60348802 | 825 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
826 | atomic_inc(¤t->sighand->count); |
827 | return 0; | |
828 | } | |
829 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 830 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
831 | if (!sig) |
832 | return -ENOMEM; | |
1da177e4 LT |
833 | atomic_set(&sig->count, 1); |
834 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
835 | return 0; | |
836 | } | |
837 | ||
a7e5328a | 838 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 839 | { |
c81addc9 ON |
840 | if (atomic_dec_and_test(&sighand->count)) |
841 | kmem_cache_free(sighand_cachep, sighand); | |
842 | } | |
843 | ||
f06febc9 FM |
844 | |
845 | /* | |
846 | * Initialize POSIX timer handling for a thread group. | |
847 | */ | |
848 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
849 | { | |
78d7d407 JS |
850 | unsigned long cpu_limit; |
851 | ||
f06febc9 FM |
852 | /* Thread group counters. */ |
853 | thread_group_cputime_init(sig); | |
854 | ||
78d7d407 JS |
855 | cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
856 | if (cpu_limit != RLIM_INFINITY) { | |
857 | sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit); | |
6279a751 ON |
858 | sig->cputimer.running = 1; |
859 | } | |
860 | ||
f06febc9 FM |
861 | /* The timer lists. */ |
862 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
863 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
864 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
865 | } | |
866 | ||
a39bc516 | 867 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
868 | { |
869 | struct signal_struct *sig; | |
1da177e4 | 870 | |
4ab6c083 | 871 | if (clone_flags & CLONE_THREAD) |
490dea45 | 872 | return 0; |
490dea45 | 873 | |
a56704ef | 874 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
875 | tsk->signal = sig; |
876 | if (!sig) | |
877 | return -ENOMEM; | |
878 | ||
ea6d290c | 879 | atomic_set(&sig->sigcnt, 1); |
1da177e4 LT |
880 | atomic_set(&sig->count, 1); |
881 | atomic_set(&sig->live, 1); | |
882 | init_waitqueue_head(&sig->wait_chldexit); | |
b3bfa0cb SB |
883 | if (clone_flags & CLONE_NEWPID) |
884 | sig->flags |= SIGNAL_UNKILLABLE; | |
db51aecc | 885 | sig->curr_target = tsk; |
1da177e4 LT |
886 | init_sigpending(&sig->shared_pending); |
887 | INIT_LIST_HEAD(&sig->posix_timers); | |
888 | ||
c9cb2e3d | 889 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 890 | sig->real_timer.function = it_real_fn; |
1da177e4 | 891 | |
1da177e4 LT |
892 | task_lock(current->group_leader); |
893 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
894 | task_unlock(current->group_leader); | |
895 | ||
6279a751 ON |
896 | posix_cpu_timers_init_group(sig); |
897 | ||
522ed776 MT |
898 | tty_audit_fork(sig); |
899 | ||
28b83c51 KM |
900 | sig->oom_adj = current->signal->oom_adj; |
901 | ||
1da177e4 LT |
902 | return 0; |
903 | } | |
904 | ||
a39bc516 | 905 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
906 | { |
907 | unsigned long new_flags = p->flags; | |
908 | ||
83144186 | 909 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 | 910 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 911 | new_flags |= PF_STARTING; |
1da177e4 | 912 | p->flags = new_flags; |
2e131895 | 913 | clear_freeze_flag(p); |
1da177e4 LT |
914 | } |
915 | ||
17da2bd9 | 916 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
917 | { |
918 | current->clear_child_tid = tidptr; | |
919 | ||
b488893a | 920 | return task_pid_vnr(current); |
1da177e4 LT |
921 | } |
922 | ||
a39bc516 | 923 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 924 | { |
1d615482 | 925 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 926 | #ifdef CONFIG_RT_MUTEXES |
1d615482 | 927 | plist_head_init_raw(&p->pi_waiters, &p->pi_lock); |
23f78d4a | 928 | p->pi_blocked_on = NULL; |
23f78d4a IM |
929 | #endif |
930 | } | |
931 | ||
cf475ad2 BS |
932 | #ifdef CONFIG_MM_OWNER |
933 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
934 | { | |
935 | mm->owner = p; | |
936 | } | |
937 | #endif /* CONFIG_MM_OWNER */ | |
938 | ||
f06febc9 FM |
939 | /* |
940 | * Initialize POSIX timer handling for a single task. | |
941 | */ | |
942 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
943 | { | |
944 | tsk->cputime_expires.prof_exp = cputime_zero; | |
945 | tsk->cputime_expires.virt_exp = cputime_zero; | |
946 | tsk->cputime_expires.sched_exp = 0; | |
947 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
948 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
949 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
950 | } | |
951 | ||
1da177e4 LT |
952 | /* |
953 | * This creates a new process as a copy of the old one, | |
954 | * but does not actually start it yet. | |
955 | * | |
956 | * It copies the registers, and all the appropriate | |
957 | * parts of the process environment (as per the clone | |
958 | * flags). The actual kick-off is left to the caller. | |
959 | */ | |
36c8b586 IM |
960 | static struct task_struct *copy_process(unsigned long clone_flags, |
961 | unsigned long stack_start, | |
962 | struct pt_regs *regs, | |
963 | unsigned long stack_size, | |
36c8b586 | 964 | int __user *child_tidptr, |
09a05394 RM |
965 | struct pid *pid, |
966 | int trace) | |
1da177e4 LT |
967 | { |
968 | int retval; | |
a24efe62 | 969 | struct task_struct *p; |
b4f48b63 | 970 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
971 | |
972 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
973 | return ERR_PTR(-EINVAL); | |
974 | ||
975 | /* | |
976 | * Thread groups must share signals as well, and detached threads | |
977 | * can only be started up within the thread group. | |
978 | */ | |
979 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
980 | return ERR_PTR(-EINVAL); | |
981 | ||
982 | /* | |
983 | * Shared signal handlers imply shared VM. By way of the above, | |
984 | * thread groups also imply shared VM. Blocking this case allows | |
985 | * for various simplifications in other code. | |
986 | */ | |
987 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
988 | return ERR_PTR(-EINVAL); | |
989 | ||
123be07b SB |
990 | /* |
991 | * Siblings of global init remain as zombies on exit since they are | |
992 | * not reaped by their parent (swapper). To solve this and to avoid | |
993 | * multi-rooted process trees, prevent global and container-inits | |
994 | * from creating siblings. | |
995 | */ | |
996 | if ((clone_flags & CLONE_PARENT) && | |
997 | current->signal->flags & SIGNAL_UNKILLABLE) | |
998 | return ERR_PTR(-EINVAL); | |
999 | ||
1da177e4 LT |
1000 | retval = security_task_create(clone_flags); |
1001 | if (retval) | |
1002 | goto fork_out; | |
1003 | ||
1004 | retval = -ENOMEM; | |
1005 | p = dup_task_struct(current); | |
1006 | if (!p) | |
1007 | goto fork_out; | |
1008 | ||
f7e8b616 SR |
1009 | ftrace_graph_init_task(p); |
1010 | ||
bea493a0 PZ |
1011 | rt_mutex_init_task(p); |
1012 | ||
d12c1a37 | 1013 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1014 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1015 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1016 | #endif | |
1da177e4 | 1017 | retval = -EAGAIN; |
3b11a1de | 1018 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1019 | task_rlimit(p, RLIMIT_NPROC)) { |
1da177e4 | 1020 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && |
18b6e041 | 1021 | p->real_cred->user != INIT_USER) |
1da177e4 LT |
1022 | goto bad_fork_free; |
1023 | } | |
1024 | ||
f1752eec DH |
1025 | retval = copy_creds(p, clone_flags); |
1026 | if (retval < 0) | |
1027 | goto bad_fork_free; | |
1da177e4 LT |
1028 | |
1029 | /* | |
1030 | * If multiple threads are within copy_process(), then this check | |
1031 | * triggers too late. This doesn't hurt, the check is only there | |
1032 | * to stop root fork bombs. | |
1033 | */ | |
04ec93fe | 1034 | retval = -EAGAIN; |
1da177e4 LT |
1035 | if (nr_threads >= max_threads) |
1036 | goto bad_fork_cleanup_count; | |
1037 | ||
a1261f54 | 1038 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1039 | goto bad_fork_cleanup_count; |
1040 | ||
1da177e4 | 1041 | p->did_exec = 0; |
ca74e92b | 1042 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1043 | copy_flags(clone_flags, p); |
1da177e4 LT |
1044 | INIT_LIST_HEAD(&p->children); |
1045 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1046 | rcu_copy_process(p); |
1da177e4 LT |
1047 | p->vfork_done = NULL; |
1048 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1049 | |
1da177e4 LT |
1050 | init_sigpending(&p->pending); |
1051 | ||
1052 | p->utime = cputime_zero; | |
1053 | p->stime = cputime_zero; | |
9ac52315 | 1054 | p->gtime = cputime_zero; |
c66f08be MN |
1055 | p->utimescaled = cputime_zero; |
1056 | p->stimescaled = cputime_zero; | |
d99ca3b9 | 1057 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
73a2bcb0 | 1058 | p->prev_utime = cputime_zero; |
9301899b | 1059 | p->prev_stime = cputime_zero; |
d99ca3b9 | 1060 | #endif |
a3a2e76c KH |
1061 | #if defined(SPLIT_RSS_COUNTING) |
1062 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1063 | #endif | |
172ba844 | 1064 | |
6976675d AV |
1065 | p->default_timer_slack_ns = current->timer_slack_ns; |
1066 | ||
5995477a | 1067 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1068 | acct_clear_integrals(p); |
1069 | ||
f06febc9 | 1070 | posix_cpu_timers_init(p); |
1da177e4 LT |
1071 | |
1072 | p->lock_depth = -1; /* -1 = no lock */ | |
1073 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1074 | p->real_start_time = p->start_time; |
1075 | monotonic_to_bootbased(&p->real_start_time); | |
1da177e4 | 1076 | p->io_context = NULL; |
1da177e4 | 1077 | p->audit_context = NULL; |
b4f48b63 | 1078 | cgroup_fork(p); |
1da177e4 | 1079 | #ifdef CONFIG_NUMA |
846a16bf | 1080 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1081 | if (IS_ERR(p->mempolicy)) { |
1082 | retval = PTR_ERR(p->mempolicy); | |
1083 | p->mempolicy = NULL; | |
b4f48b63 | 1084 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1085 | } |
c61afb18 | 1086 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1087 | #endif |
0ac0c0d0 JS |
1088 | #ifdef CONFIG_CPUSETS |
1089 | p->cpuset_mem_spread_rotor = node_random(p->mems_allowed); | |
1090 | p->cpuset_slab_spread_rotor = node_random(p->mems_allowed); | |
1091 | #endif | |
de30a2b3 IM |
1092 | #ifdef CONFIG_TRACE_IRQFLAGS |
1093 | p->irq_events = 0; | |
b36e4758 RK |
1094 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1095 | p->hardirqs_enabled = 1; | |
1096 | #else | |
de30a2b3 | 1097 | p->hardirqs_enabled = 0; |
b36e4758 | 1098 | #endif |
de30a2b3 IM |
1099 | p->hardirq_enable_ip = 0; |
1100 | p->hardirq_enable_event = 0; | |
1101 | p->hardirq_disable_ip = _THIS_IP_; | |
1102 | p->hardirq_disable_event = 0; | |
1103 | p->softirqs_enabled = 1; | |
1104 | p->softirq_enable_ip = _THIS_IP_; | |
1105 | p->softirq_enable_event = 0; | |
1106 | p->softirq_disable_ip = 0; | |
1107 | p->softirq_disable_event = 0; | |
1108 | p->hardirq_context = 0; | |
1109 | p->softirq_context = 0; | |
1110 | #endif | |
fbb9ce95 IM |
1111 | #ifdef CONFIG_LOCKDEP |
1112 | p->lockdep_depth = 0; /* no locks held yet */ | |
1113 | p->curr_chain_key = 0; | |
1114 | p->lockdep_recursion = 0; | |
1115 | #endif | |
1da177e4 | 1116 | |
408894ee IM |
1117 | #ifdef CONFIG_DEBUG_MUTEXES |
1118 | p->blocked_on = NULL; /* not blocked yet */ | |
1119 | #endif | |
569b846d KH |
1120 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
1121 | p->memcg_batch.do_batch = 0; | |
1122 | p->memcg_batch.memcg = NULL; | |
1123 | #endif | |
0f481406 | 1124 | |
3c90e6e9 SV |
1125 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1126 | sched_fork(p, clone_flags); | |
6ab423e0 | 1127 | |
cdd6c482 | 1128 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1129 | if (retval) |
1130 | goto bad_fork_cleanup_policy; | |
3c90e6e9 | 1131 | |
1da177e4 | 1132 | if ((retval = audit_alloc(p))) |
f1752eec | 1133 | goto bad_fork_cleanup_policy; |
1da177e4 LT |
1134 | /* copy all the process information */ |
1135 | if ((retval = copy_semundo(clone_flags, p))) | |
1136 | goto bad_fork_cleanup_audit; | |
1137 | if ((retval = copy_files(clone_flags, p))) | |
1138 | goto bad_fork_cleanup_semundo; | |
1139 | if ((retval = copy_fs(clone_flags, p))) | |
1140 | goto bad_fork_cleanup_files; | |
1141 | if ((retval = copy_sighand(clone_flags, p))) | |
1142 | goto bad_fork_cleanup_fs; | |
1143 | if ((retval = copy_signal(clone_flags, p))) | |
1144 | goto bad_fork_cleanup_sighand; | |
1145 | if ((retval = copy_mm(clone_flags, p))) | |
1146 | goto bad_fork_cleanup_signal; | |
ab516013 | 1147 | if ((retval = copy_namespaces(clone_flags, p))) |
d84f4f99 | 1148 | goto bad_fork_cleanup_mm; |
fadad878 | 1149 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1150 | goto bad_fork_cleanup_namespaces; |
6f2c55b8 | 1151 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
1da177e4 | 1152 | if (retval) |
fd0928df | 1153 | goto bad_fork_cleanup_io; |
1da177e4 | 1154 | |
425fb2b4 PE |
1155 | if (pid != &init_struct_pid) { |
1156 | retval = -ENOMEM; | |
61bce0f1 | 1157 | pid = alloc_pid(p->nsproxy->pid_ns); |
425fb2b4 | 1158 | if (!pid) |
fd0928df | 1159 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1160 | |
1161 | if (clone_flags & CLONE_NEWPID) { | |
61bce0f1 | 1162 | retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); |
6f4e6433 PE |
1163 | if (retval < 0) |
1164 | goto bad_fork_free_pid; | |
1165 | } | |
425fb2b4 PE |
1166 | } |
1167 | ||
1168 | p->pid = pid_nr(pid); | |
1169 | p->tgid = p->pid; | |
1170 | if (clone_flags & CLONE_THREAD) | |
1171 | p->tgid = current->tgid; | |
1172 | ||
e885dcde SH |
1173 | if (current->nsproxy != p->nsproxy) { |
1174 | retval = ns_cgroup_clone(p, pid); | |
1175 | if (retval) | |
f7e8b616 | 1176 | goto bad_fork_free_pid; |
e885dcde SH |
1177 | } |
1178 | ||
1da177e4 LT |
1179 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1180 | /* | |
1181 | * Clear TID on mm_release()? | |
1182 | */ | |
1183 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1184 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1185 | p->robust_list = NULL; |
1186 | #ifdef CONFIG_COMPAT | |
1187 | p->compat_robust_list = NULL; | |
1188 | #endif | |
c87e2837 IM |
1189 | INIT_LIST_HEAD(&p->pi_state_list); |
1190 | p->pi_state_cache = NULL; | |
42b2dd0a | 1191 | #endif |
f9a3879a GM |
1192 | /* |
1193 | * sigaltstack should be cleared when sharing the same VM | |
1194 | */ | |
1195 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1196 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1197 | ||
1da177e4 | 1198 | /* |
6580807d ON |
1199 | * Syscall tracing and stepping should be turned off in the |
1200 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1201 | */ |
6580807d | 1202 | user_disable_single_step(p); |
1da177e4 | 1203 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1204 | #ifdef TIF_SYSCALL_EMU |
1205 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1206 | #endif | |
9745512c | 1207 | clear_all_latency_tracing(p); |
1da177e4 | 1208 | |
1da177e4 LT |
1209 | /* ok, now we should be set up.. */ |
1210 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1211 | p->pdeath_signal = 0; | |
1212 | p->exit_state = 0; | |
1213 | ||
1da177e4 LT |
1214 | /* |
1215 | * Ok, make it visible to the rest of the system. | |
1216 | * We dont wake it up yet. | |
1217 | */ | |
1218 | p->group_leader = p; | |
47e65328 | 1219 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1220 | |
b4f48b63 PM |
1221 | /* Now that the task is set up, run cgroup callbacks if |
1222 | * necessary. We need to run them before the task is visible | |
1223 | * on the tasklist. */ | |
1224 | cgroup_fork_callbacks(p); | |
1225 | cgroup_callbacks_done = 1; | |
1226 | ||
1da177e4 LT |
1227 | /* Need tasklist lock for parent etc handling! */ |
1228 | write_lock_irq(&tasklist_lock); | |
1229 | ||
1da177e4 | 1230 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1231 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1232 | p->real_parent = current->real_parent; |
2d5516cb ON |
1233 | p->parent_exec_id = current->parent_exec_id; |
1234 | } else { | |
1da177e4 | 1235 | p->real_parent = current; |
2d5516cb ON |
1236 | p->parent_exec_id = current->self_exec_id; |
1237 | } | |
1da177e4 | 1238 | |
3f17da69 | 1239 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1240 | |
1241 | /* | |
1242 | * Process group and session signals need to be delivered to just the | |
1243 | * parent before the fork or both the parent and the child after the | |
1244 | * fork. Restart if a signal comes in before we add the new process to | |
1245 | * it's process group. | |
1246 | * A fatal signal pending means that current will exit, so the new | |
1247 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1248 | */ | |
23ff4440 | 1249 | recalc_sigpending(); |
4a2c7a78 ON |
1250 | if (signal_pending(current)) { |
1251 | spin_unlock(¤t->sighand->siglock); | |
1252 | write_unlock_irq(&tasklist_lock); | |
1253 | retval = -ERESTARTNOINTR; | |
f7e8b616 | 1254 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1255 | } |
1256 | ||
1da177e4 | 1257 | if (clone_flags & CLONE_THREAD) { |
ea6d290c | 1258 | atomic_inc(¤t->signal->sigcnt); |
4ab6c083 ON |
1259 | atomic_inc(¤t->signal->count); |
1260 | atomic_inc(¤t->signal->live); | |
1da177e4 | 1261 | p->group_leader = current->group_leader; |
47e65328 | 1262 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 LT |
1263 | } |
1264 | ||
73b9ebfe | 1265 | if (likely(p->pid)) { |
09a05394 | 1266 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1267 | |
1268 | if (thread_group_leader(p)) { | |
5cd17569 | 1269 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1270 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1271 | |
fea9d175 | 1272 | p->signal->leader_pid = pid; |
9c9f4ded | 1273 | p->signal->tty = tty_kref_get(current->signal->tty); |
5cd17569 EB |
1274 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1275 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
9cd80bbb | 1276 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 1277 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1278 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1279 | } |
85868995 | 1280 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1281 | nr_threads++; |
1da177e4 LT |
1282 | } |
1283 | ||
1da177e4 | 1284 | total_forks++; |
3f17da69 | 1285 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1286 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1287 | proc_fork_connector(p); |
817929ec | 1288 | cgroup_post_fork(p); |
cdd6c482 | 1289 | perf_event_fork(p); |
1da177e4 LT |
1290 | return p; |
1291 | ||
425fb2b4 PE |
1292 | bad_fork_free_pid: |
1293 | if (pid != &init_struct_pid) | |
1294 | free_pid(pid); | |
fd0928df | 1295 | bad_fork_cleanup_io: |
b69f2292 LR |
1296 | if (p->io_context) |
1297 | exit_io_context(p); | |
ab516013 | 1298 | bad_fork_cleanup_namespaces: |
444f378b | 1299 | exit_task_namespaces(p); |
1da177e4 LT |
1300 | bad_fork_cleanup_mm: |
1301 | if (p->mm) | |
1302 | mmput(p->mm); | |
1303 | bad_fork_cleanup_signal: | |
4ab6c083 | 1304 | if (!(clone_flags & CLONE_THREAD)) |
ea6d290c | 1305 | free_signal_struct(p->signal); |
1da177e4 | 1306 | bad_fork_cleanup_sighand: |
a7e5328a | 1307 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1308 | bad_fork_cleanup_fs: |
1309 | exit_fs(p); /* blocking */ | |
1310 | bad_fork_cleanup_files: | |
1311 | exit_files(p); /* blocking */ | |
1312 | bad_fork_cleanup_semundo: | |
1313 | exit_sem(p); | |
1314 | bad_fork_cleanup_audit: | |
1315 | audit_free(p); | |
1da177e4 | 1316 | bad_fork_cleanup_policy: |
cdd6c482 | 1317 | perf_event_free_task(p); |
1da177e4 | 1318 | #ifdef CONFIG_NUMA |
f0be3d32 | 1319 | mpol_put(p->mempolicy); |
b4f48b63 | 1320 | bad_fork_cleanup_cgroup: |
1da177e4 | 1321 | #endif |
b4f48b63 | 1322 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1323 | delayacct_tsk_free(p); |
a1261f54 | 1324 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 | 1325 | bad_fork_cleanup_count: |
d84f4f99 | 1326 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1327 | exit_creds(p); |
1da177e4 LT |
1328 | bad_fork_free: |
1329 | free_task(p); | |
fe7d37d1 ON |
1330 | fork_out: |
1331 | return ERR_PTR(retval); | |
1da177e4 LT |
1332 | } |
1333 | ||
6b2fb3c6 | 1334 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1335 | { |
1336 | memset(regs, 0, sizeof(struct pt_regs)); | |
1337 | return regs; | |
1338 | } | |
1339 | ||
9abcf40b | 1340 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1341 | { |
36c8b586 | 1342 | struct task_struct *task; |
1da177e4 LT |
1343 | struct pt_regs regs; |
1344 | ||
30e49c26 | 1345 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1346 | &init_struct_pid, 0); |
753ca4f3 AM |
1347 | if (!IS_ERR(task)) |
1348 | init_idle(task, cpu); | |
73b9ebfe | 1349 | |
1da177e4 LT |
1350 | return task; |
1351 | } | |
1352 | ||
1da177e4 LT |
1353 | /* |
1354 | * Ok, this is the main fork-routine. | |
1355 | * | |
1356 | * It copies the process, and if successful kick-starts | |
1357 | * it and waits for it to finish using the VM if required. | |
1358 | */ | |
1359 | long do_fork(unsigned long clone_flags, | |
1360 | unsigned long stack_start, | |
1361 | struct pt_regs *regs, | |
1362 | unsigned long stack_size, | |
1363 | int __user *parent_tidptr, | |
1364 | int __user *child_tidptr) | |
1365 | { | |
1366 | struct task_struct *p; | |
1367 | int trace = 0; | |
92476d7f | 1368 | long nr; |
1da177e4 | 1369 | |
18b6e041 SH |
1370 | /* |
1371 | * Do some preliminary argument and permissions checking before we | |
1372 | * actually start allocating stuff | |
1373 | */ | |
1374 | if (clone_flags & CLONE_NEWUSER) { | |
1375 | if (clone_flags & CLONE_THREAD) | |
1376 | return -EINVAL; | |
1377 | /* hopefully this check will go away when userns support is | |
1378 | * complete | |
1379 | */ | |
7657d904 SH |
1380 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
1381 | !capable(CAP_SETGID)) | |
18b6e041 SH |
1382 | return -EPERM; |
1383 | } | |
1384 | ||
bdff746a AM |
1385 | /* |
1386 | * We hope to recycle these flags after 2.6.26 | |
1387 | */ | |
1388 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1389 | static int __read_mostly count = 100; | |
1390 | ||
1391 | if (count > 0 && printk_ratelimit()) { | |
1392 | char comm[TASK_COMM_LEN]; | |
1393 | ||
1394 | count--; | |
1395 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1396 | "clone flags 0x%lx\n", | |
1397 | get_task_comm(comm, current), | |
1398 | clone_flags & CLONE_STOPPED); | |
1399 | } | |
1400 | } | |
1401 | ||
09a05394 RM |
1402 | /* |
1403 | * When called from kernel_thread, don't do user tracing stuff. | |
1404 | */ | |
1405 | if (likely(user_mode(regs))) | |
1406 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1407 | |
a6f5e063 | 1408 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1409 | child_tidptr, NULL, trace); |
1da177e4 LT |
1410 | /* |
1411 | * Do this prior waking up the new thread - the thread pointer | |
1412 | * might get invalid after that point, if the thread exits quickly. | |
1413 | */ | |
1414 | if (!IS_ERR(p)) { | |
1415 | struct completion vfork; | |
1416 | ||
0a16b607 MD |
1417 | trace_sched_process_fork(current, p); |
1418 | ||
6c5f3e7b | 1419 | nr = task_pid_vnr(p); |
30e49c26 PE |
1420 | |
1421 | if (clone_flags & CLONE_PARENT_SETTID) | |
1422 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1423 | |
1da177e4 LT |
1424 | if (clone_flags & CLONE_VFORK) { |
1425 | p->vfork_done = &vfork; | |
1426 | init_completion(&vfork); | |
1427 | } | |
1428 | ||
a64e6494 | 1429 | audit_finish_fork(p); |
087eb437 | 1430 | tracehook_report_clone(regs, clone_flags, nr, p); |
09a05394 RM |
1431 | |
1432 | /* | |
1433 | * We set PF_STARTING at creation in case tracing wants to | |
1434 | * use this to distinguish a fully live task from one that | |
1435 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1436 | * clear it and set the child going. | |
1437 | */ | |
1438 | p->flags &= ~PF_STARTING; | |
1439 | ||
1440 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1da177e4 LT |
1441 | /* |
1442 | * We'll start up with an immediate SIGSTOP. | |
1443 | */ | |
1444 | sigaddset(&p->pending.signal, SIGSTOP); | |
1445 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
d9ae90ac | 1446 | __set_task_state(p, TASK_STOPPED); |
09a05394 RM |
1447 | } else { |
1448 | wake_up_new_task(p, clone_flags); | |
1da177e4 LT |
1449 | } |
1450 | ||
09a05394 RM |
1451 | tracehook_report_clone_complete(trace, regs, |
1452 | clone_flags, nr, p); | |
1453 | ||
1da177e4 | 1454 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1455 | freezer_do_not_count(); |
1da177e4 | 1456 | wait_for_completion(&vfork); |
ba96a0c8 | 1457 | freezer_count(); |
daded34b | 1458 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1459 | } |
1460 | } else { | |
92476d7f | 1461 | nr = PTR_ERR(p); |
1da177e4 | 1462 | } |
92476d7f | 1463 | return nr; |
1da177e4 LT |
1464 | } |
1465 | ||
5fd63b30 RT |
1466 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1467 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1468 | #endif | |
1469 | ||
51cc5068 | 1470 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1471 | { |
1472 | struct sighand_struct *sighand = data; | |
1473 | ||
a35afb83 | 1474 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1475 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1476 | } |
1477 | ||
1da177e4 LT |
1478 | void __init proc_caches_init(void) |
1479 | { | |
1480 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1481 | sizeof(struct sighand_struct), 0, | |
2dff4405 VN |
1482 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
1483 | SLAB_NOTRACK, sighand_ctor); | |
1da177e4 LT |
1484 | signal_cachep = kmem_cache_create("signal_cache", |
1485 | sizeof(struct signal_struct), 0, | |
2dff4405 | 1486 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1487 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 1488 | sizeof(struct files_struct), 0, |
2dff4405 | 1489 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1490 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 1491 | sizeof(struct fs_struct), 0, |
2dff4405 | 1492 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
1da177e4 | 1493 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1494 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
2dff4405 | 1495 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
33e5d769 | 1496 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
8feae131 | 1497 | mmap_init(); |
1da177e4 | 1498 | } |
cf2e340f | 1499 | |
cf2e340f JD |
1500 | /* |
1501 | * Check constraints on flags passed to the unshare system call and | |
1502 | * force unsharing of additional process context as appropriate. | |
1503 | */ | |
a39bc516 | 1504 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1505 | { |
1506 | /* | |
1507 | * If unsharing a thread from a thread group, must also | |
1508 | * unshare vm. | |
1509 | */ | |
1510 | if (*flags_ptr & CLONE_THREAD) | |
1511 | *flags_ptr |= CLONE_VM; | |
1512 | ||
1513 | /* | |
1514 | * If unsharing vm, must also unshare signal handlers. | |
1515 | */ | |
1516 | if (*flags_ptr & CLONE_VM) | |
1517 | *flags_ptr |= CLONE_SIGHAND; | |
1518 | ||
1519 | /* | |
1520 | * If unsharing signal handlers and the task was created | |
1521 | * using CLONE_THREAD, then must unshare the thread | |
1522 | */ | |
1523 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1524 | (atomic_read(¤t->signal->count) > 1)) | |
1525 | *flags_ptr |= CLONE_THREAD; | |
1526 | ||
1527 | /* | |
1528 | * If unsharing namespace, must also unshare filesystem information. | |
1529 | */ | |
1530 | if (*flags_ptr & CLONE_NEWNS) | |
1531 | *flags_ptr |= CLONE_FS; | |
1532 | } | |
1533 | ||
1534 | /* | |
1535 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1536 | */ | |
1537 | static int unshare_thread(unsigned long unshare_flags) | |
1538 | { | |
1539 | if (unshare_flags & CLONE_THREAD) | |
1540 | return -EINVAL; | |
1541 | ||
1542 | return 0; | |
1543 | } | |
1544 | ||
1545 | /* | |
99d1419d | 1546 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1547 | */ |
1548 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1549 | { | |
1550 | struct fs_struct *fs = current->fs; | |
1551 | ||
498052bb AV |
1552 | if (!(unshare_flags & CLONE_FS) || !fs) |
1553 | return 0; | |
1554 | ||
1555 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1556 | if (fs->users == 1) | |
1557 | return 0; | |
1558 | ||
1559 | *new_fsp = copy_fs_struct(fs); | |
1560 | if (!*new_fsp) | |
1561 | return -ENOMEM; | |
cf2e340f JD |
1562 | |
1563 | return 0; | |
1564 | } | |
1565 | ||
cf2e340f | 1566 | /* |
dae3c5a0 | 1567 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1568 | */ |
1569 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1570 | { | |
1571 | struct sighand_struct *sigh = current->sighand; | |
1572 | ||
dae3c5a0 | 1573 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1574 | return -EINVAL; |
1575 | else | |
1576 | return 0; | |
1577 | } | |
1578 | ||
1579 | /* | |
a0a7ec30 | 1580 | * Unshare vm if it is being shared |
cf2e340f JD |
1581 | */ |
1582 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1583 | { | |
1584 | struct mm_struct *mm = current->mm; | |
1585 | ||
1586 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1587 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1588 | return -EINVAL; |
a0a7ec30 | 1589 | } |
cf2e340f JD |
1590 | |
1591 | return 0; | |
cf2e340f JD |
1592 | } |
1593 | ||
1594 | /* | |
a016f338 | 1595 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1596 | */ |
1597 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1598 | { | |
1599 | struct files_struct *fd = current->files; | |
a016f338 | 1600 | int error = 0; |
cf2e340f JD |
1601 | |
1602 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1603 | (fd && atomic_read(&fd->count) > 1)) { |
1604 | *new_fdp = dup_fd(fd, &error); | |
1605 | if (!*new_fdp) | |
1606 | return error; | |
1607 | } | |
cf2e340f JD |
1608 | |
1609 | return 0; | |
1610 | } | |
1611 | ||
cf2e340f JD |
1612 | /* |
1613 | * unshare allows a process to 'unshare' part of the process | |
1614 | * context which was originally shared using clone. copy_* | |
1615 | * functions used by do_fork() cannot be used here directly | |
1616 | * because they modify an inactive task_struct that is being | |
1617 | * constructed. Here we are modifying the current, active, | |
1618 | * task_struct. | |
1619 | */ | |
6559eed8 | 1620 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f JD |
1621 | { |
1622 | int err = 0; | |
1623 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1624 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1625 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1626 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1627 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1628 | int do_sysvsem = 0; |
cf2e340f JD |
1629 | |
1630 | check_unshare_flags(&unshare_flags); | |
1631 | ||
06f9d4f9 EB |
1632 | /* Return -EINVAL for all unsupported flags */ |
1633 | err = -EINVAL; | |
1634 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1635 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
18b6e041 | 1636 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) |
06f9d4f9 EB |
1637 | goto bad_unshare_out; |
1638 | ||
6013f67f MS |
1639 | /* |
1640 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1641 | * to a new ipc namespace, the semaphore arrays from the old | |
1642 | * namespace are unreachable. | |
1643 | */ | |
1644 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1645 | do_sysvsem = 1; |
cf2e340f JD |
1646 | if ((err = unshare_thread(unshare_flags))) |
1647 | goto bad_unshare_out; | |
1648 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1649 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1650 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1651 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1652 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1653 | goto bad_unshare_cleanup_sigh; | |
1654 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1655 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1656 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1657 | new_fs))) | |
9edff4ab | 1658 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1659 | |
9edff4ab MS |
1660 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1661 | if (do_sysvsem) { | |
1662 | /* | |
1663 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1664 | */ | |
1665 | exit_sem(current); | |
1666 | } | |
ab516013 | 1667 | |
c0b2fc31 | 1668 | if (new_nsproxy) { |
cf7b708c PE |
1669 | switch_task_namespaces(current, new_nsproxy); |
1670 | new_nsproxy = NULL; | |
c0b2fc31 | 1671 | } |
cf2e340f | 1672 | |
cf7b708c PE |
1673 | task_lock(current); |
1674 | ||
cf2e340f JD |
1675 | if (new_fs) { |
1676 | fs = current->fs; | |
498052bb | 1677 | write_lock(&fs->lock); |
cf2e340f | 1678 | current->fs = new_fs; |
498052bb AV |
1679 | if (--fs->users) |
1680 | new_fs = NULL; | |
1681 | else | |
1682 | new_fs = fs; | |
1683 | write_unlock(&fs->lock); | |
cf2e340f JD |
1684 | } |
1685 | ||
cf2e340f JD |
1686 | if (new_mm) { |
1687 | mm = current->mm; | |
1688 | active_mm = current->active_mm; | |
1689 | current->mm = new_mm; | |
1690 | current->active_mm = new_mm; | |
1691 | activate_mm(active_mm, new_mm); | |
1692 | new_mm = mm; | |
1693 | } | |
1694 | ||
1695 | if (new_fd) { | |
1696 | fd = current->files; | |
1697 | current->files = new_fd; | |
1698 | new_fd = fd; | |
1699 | } | |
1700 | ||
1701 | task_unlock(current); | |
1702 | } | |
1703 | ||
c0b2fc31 | 1704 | if (new_nsproxy) |
444f378b | 1705 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1706 | |
cf2e340f JD |
1707 | bad_unshare_cleanup_fd: |
1708 | if (new_fd) | |
1709 | put_files_struct(new_fd); | |
1710 | ||
1711 | bad_unshare_cleanup_vm: | |
1712 | if (new_mm) | |
1713 | mmput(new_mm); | |
1714 | ||
1715 | bad_unshare_cleanup_sigh: | |
1716 | if (new_sigh) | |
1717 | if (atomic_dec_and_test(&new_sigh->count)) | |
1718 | kmem_cache_free(sighand_cachep, new_sigh); | |
1719 | ||
cf2e340f JD |
1720 | bad_unshare_cleanup_fs: |
1721 | if (new_fs) | |
498052bb | 1722 | free_fs_struct(new_fs); |
cf2e340f JD |
1723 | |
1724 | bad_unshare_cleanup_thread: | |
1725 | bad_unshare_out: | |
1726 | return err; | |
1727 | } | |
3b125388 AV |
1728 | |
1729 | /* | |
1730 | * Helper to unshare the files of the current task. | |
1731 | * We don't want to expose copy_files internals to | |
1732 | * the exec layer of the kernel. | |
1733 | */ | |
1734 | ||
1735 | int unshare_files(struct files_struct **displaced) | |
1736 | { | |
1737 | struct task_struct *task = current; | |
50704516 | 1738 | struct files_struct *copy = NULL; |
3b125388 AV |
1739 | int error; |
1740 | ||
1741 | error = unshare_fd(CLONE_FILES, ©); | |
1742 | if (error || !copy) { | |
1743 | *displaced = NULL; | |
1744 | return error; | |
1745 | } | |
1746 | *displaced = task->files; | |
1747 | task_lock(task); | |
1748 | task->files = copy; | |
1749 | task_unlock(task); | |
1750 | return 0; | |
1751 | } |