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> |
1da177e4 LT |
67 | |
68 | #include <asm/pgtable.h> | |
69 | #include <asm/pgalloc.h> | |
70 | #include <asm/uaccess.h> | |
71 | #include <asm/mmu_context.h> | |
72 | #include <asm/cacheflush.h> | |
73 | #include <asm/tlbflush.h> | |
74 | ||
ad8d75ff SR |
75 | #include <trace/events/sched.h> |
76 | ||
1da177e4 LT |
77 | /* |
78 | * Protected counters by write_lock_irq(&tasklist_lock) | |
79 | */ | |
80 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
81 | int nr_threads; /* The idle threads do not count.. */ | |
82 | ||
83 | int max_threads; /* tunable limit on nr_threads */ | |
84 | ||
85 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
86 | ||
c59923a1 | 87 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
88 | |
89 | int nr_processes(void) | |
90 | { | |
91 | int cpu; | |
92 | int total = 0; | |
93 | ||
94 | for_each_online_cpu(cpu) | |
95 | total += per_cpu(process_counts, cpu); | |
96 | ||
97 | return total; | |
98 | } | |
99 | ||
100 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
101 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
102 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 103 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
104 | #endif |
105 | ||
b69c49b7 FT |
106 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
107 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
108 | { | |
109 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
110 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
111 | #else | |
112 | gfp_t mask = GFP_KERNEL; | |
113 | #endif | |
114 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
115 | } | |
116 | ||
117 | static inline void free_thread_info(struct thread_info *ti) | |
118 | { | |
119 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
120 | } | |
121 | #endif | |
122 | ||
1da177e4 | 123 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 124 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
125 | |
126 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 127 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
128 | |
129 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 130 | struct kmem_cache *files_cachep; |
1da177e4 LT |
131 | |
132 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 133 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
134 | |
135 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 136 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
137 | |
138 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 139 | static struct kmem_cache *mm_cachep; |
1da177e4 | 140 | |
c6a7f572 KM |
141 | static void account_kernel_stack(struct thread_info *ti, int account) |
142 | { | |
143 | struct zone *zone = page_zone(virt_to_page(ti)); | |
144 | ||
145 | mod_zone_page_state(zone, NR_KERNEL_STACK, account); | |
146 | } | |
147 | ||
1da177e4 LT |
148 | void free_task(struct task_struct *tsk) |
149 | { | |
3e26c149 | 150 | prop_local_destroy_single(&tsk->dirties); |
c6a7f572 | 151 | account_kernel_stack(tsk->stack, -1); |
f7e4217b | 152 | free_thread_info(tsk->stack); |
23f78d4a | 153 | rt_mutex_debug_task_free(tsk); |
fb52607a | 154 | ftrace_graph_exit_task(tsk); |
1da177e4 LT |
155 | free_task_struct(tsk); |
156 | } | |
157 | EXPORT_SYMBOL(free_task); | |
158 | ||
158d9ebd | 159 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 160 | { |
270f722d | 161 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
162 | WARN_ON(atomic_read(&tsk->usage)); |
163 | WARN_ON(tsk == current); | |
164 | ||
e0e81739 | 165 | exit_creds(tsk); |
35df17c5 | 166 | delayacct_tsk_free(tsk); |
1da177e4 LT |
167 | |
168 | if (!profile_handoff_task(tsk)) | |
169 | free_task(tsk); | |
170 | } | |
171 | ||
2adee9b3 SS |
172 | /* |
173 | * macro override instead of weak attribute alias, to workaround | |
174 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
175 | */ | |
176 | #ifndef arch_task_cache_init | |
177 | #define arch_task_cache_init() | |
178 | #endif | |
61c4628b | 179 | |
1da177e4 LT |
180 | void __init fork_init(unsigned long mempages) |
181 | { | |
182 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
183 | #ifndef ARCH_MIN_TASKALIGN | |
184 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
185 | #endif | |
186 | /* create a slab on which task_structs can be allocated */ | |
187 | task_struct_cachep = | |
188 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
2dff4405 | 189 | ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); |
1da177e4 LT |
190 | #endif |
191 | ||
61c4628b SS |
192 | /* do the arch specific task caches init */ |
193 | arch_task_cache_init(); | |
194 | ||
1da177e4 LT |
195 | /* |
196 | * The default maximum number of threads is set to a safe | |
197 | * value: the thread structures can take up at most half | |
198 | * of memory. | |
199 | */ | |
200 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
201 | ||
202 | /* | |
203 | * we need to allow at least 20 threads to boot a system | |
204 | */ | |
205 | if(max_threads < 20) | |
206 | max_threads = 20; | |
207 | ||
208 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
209 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
210 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
211 | init_task.signal->rlim[RLIMIT_NPROC]; | |
212 | } | |
213 | ||
61c4628b SS |
214 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
215 | struct task_struct *src) | |
216 | { | |
217 | *dst = *src; | |
218 | return 0; | |
219 | } | |
220 | ||
1da177e4 LT |
221 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
222 | { | |
223 | struct task_struct *tsk; | |
224 | struct thread_info *ti; | |
7c9f8861 ES |
225 | unsigned long *stackend; |
226 | ||
3e26c149 | 227 | int err; |
1da177e4 LT |
228 | |
229 | prepare_to_copy(orig); | |
230 | ||
231 | tsk = alloc_task_struct(); | |
232 | if (!tsk) | |
233 | return NULL; | |
234 | ||
235 | ti = alloc_thread_info(tsk); | |
236 | if (!ti) { | |
237 | free_task_struct(tsk); | |
238 | return NULL; | |
239 | } | |
240 | ||
61c4628b SS |
241 | err = arch_dup_task_struct(tsk, orig); |
242 | if (err) | |
243 | goto out; | |
244 | ||
f7e4217b | 245 | tsk->stack = ti; |
3e26c149 PZ |
246 | |
247 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
248 | if (err) |
249 | goto out; | |
3e26c149 | 250 | |
10ebffde | 251 | setup_thread_stack(tsk, orig); |
7c9f8861 ES |
252 | stackend = end_of_stack(tsk); |
253 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1da177e4 | 254 | |
0a425405 AV |
255 | #ifdef CONFIG_CC_STACKPROTECTOR |
256 | tsk->stack_canary = get_random_int(); | |
257 | #endif | |
258 | ||
1da177e4 LT |
259 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
260 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 261 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 262 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 263 | tsk->btrace_seq = 0; |
6c5c9341 | 264 | #endif |
a0aa7f68 | 265 | tsk->splice_pipe = NULL; |
c6a7f572 KM |
266 | |
267 | account_kernel_stack(ti, 1); | |
268 | ||
1da177e4 | 269 | return tsk; |
61c4628b SS |
270 | |
271 | out: | |
272 | free_thread_info(ti); | |
273 | free_task_struct(tsk); | |
274 | return NULL; | |
1da177e4 LT |
275 | } |
276 | ||
277 | #ifdef CONFIG_MMU | |
a39bc516 | 278 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 279 | { |
fd3e42fc | 280 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
281 | struct rb_node **rb_link, *rb_parent; |
282 | int retval; | |
283 | unsigned long charge; | |
284 | struct mempolicy *pol; | |
285 | ||
286 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 287 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
288 | /* |
289 | * Not linked in yet - no deadlock potential: | |
290 | */ | |
291 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 292 | |
1da177e4 LT |
293 | mm->locked_vm = 0; |
294 | mm->mmap = NULL; | |
295 | mm->mmap_cache = NULL; | |
296 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 297 | mm->cached_hole_size = ~0UL; |
1da177e4 | 298 | mm->map_count = 0; |
94894244 | 299 | cpumask_clear(mm_cpumask(mm)); |
1da177e4 LT |
300 | mm->mm_rb = RB_ROOT; |
301 | rb_link = &mm->mm_rb.rb_node; | |
302 | rb_parent = NULL; | |
303 | pprev = &mm->mmap; | |
f8af4da3 HD |
304 | retval = ksm_fork(mm, oldmm); |
305 | if (retval) | |
306 | goto out; | |
1da177e4 | 307 | |
fd3e42fc | 308 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
309 | struct file *file; |
310 | ||
311 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
312 | long pages = vma_pages(mpnt); |
313 | mm->total_vm -= pages; | |
ab50b8ed | 314 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 315 | -pages); |
1da177e4 LT |
316 | continue; |
317 | } | |
318 | charge = 0; | |
319 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
320 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
321 | if (security_vm_enough_memory(len)) | |
322 | goto fail_nomem; | |
323 | charge = len; | |
324 | } | |
e94b1766 | 325 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
326 | if (!tmp) |
327 | goto fail_nomem; | |
328 | *tmp = *mpnt; | |
846a16bf | 329 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
330 | retval = PTR_ERR(pol); |
331 | if (IS_ERR(pol)) | |
332 | goto fail_nomem_policy; | |
333 | vma_set_policy(tmp, pol); | |
334 | tmp->vm_flags &= ~VM_LOCKED; | |
335 | tmp->vm_mm = mm; | |
336 | tmp->vm_next = NULL; | |
337 | anon_vma_link(tmp); | |
338 | file = tmp->vm_file; | |
339 | if (file) { | |
f3a43f3f | 340 | struct inode *inode = file->f_path.dentry->d_inode; |
b88ed205 HD |
341 | struct address_space *mapping = file->f_mapping; |
342 | ||
1da177e4 LT |
343 | get_file(file); |
344 | if (tmp->vm_flags & VM_DENYWRITE) | |
345 | atomic_dec(&inode->i_writecount); | |
b88ed205 HD |
346 | spin_lock(&mapping->i_mmap_lock); |
347 | if (tmp->vm_flags & VM_SHARED) | |
348 | mapping->i_mmap_writable++; | |
1da177e4 | 349 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
b88ed205 HD |
350 | flush_dcache_mmap_lock(mapping); |
351 | /* insert tmp into the share list, just after mpnt */ | |
1da177e4 | 352 | vma_prio_tree_add(tmp, mpnt); |
b88ed205 HD |
353 | flush_dcache_mmap_unlock(mapping); |
354 | spin_unlock(&mapping->i_mmap_lock); | |
1da177e4 LT |
355 | } |
356 | ||
a1e78772 MG |
357 | /* |
358 | * Clear hugetlb-related page reserves for children. This only | |
359 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
360 | * are not guaranteed to succeed, even if read-only | |
361 | */ | |
362 | if (is_vm_hugetlb_page(tmp)) | |
363 | reset_vma_resv_huge_pages(tmp); | |
364 | ||
1da177e4 | 365 | /* |
7ee78232 | 366 | * Link in the new vma and copy the page table entries. |
1da177e4 | 367 | */ |
1da177e4 LT |
368 | *pprev = tmp; |
369 | pprev = &tmp->vm_next; | |
370 | ||
371 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
372 | rb_link = &tmp->vm_rb.rb_right; | |
373 | rb_parent = &tmp->vm_rb; | |
374 | ||
375 | mm->map_count++; | |
0b0db14c | 376 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
377 | |
378 | if (tmp->vm_ops && tmp->vm_ops->open) | |
379 | tmp->vm_ops->open(tmp); | |
380 | ||
381 | if (retval) | |
382 | goto out; | |
383 | } | |
d6dd61c8 JF |
384 | /* a new mm has just been created */ |
385 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 386 | retval = 0; |
1da177e4 | 387 | out: |
7ee78232 | 388 | up_write(&mm->mmap_sem); |
fd3e42fc | 389 | flush_tlb_mm(oldmm); |
1da177e4 LT |
390 | up_write(&oldmm->mmap_sem); |
391 | return retval; | |
392 | fail_nomem_policy: | |
393 | kmem_cache_free(vm_area_cachep, tmp); | |
394 | fail_nomem: | |
395 | retval = -ENOMEM; | |
396 | vm_unacct_memory(charge); | |
397 | goto out; | |
398 | } | |
399 | ||
400 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
401 | { | |
402 | mm->pgd = pgd_alloc(mm); | |
403 | if (unlikely(!mm->pgd)) | |
404 | return -ENOMEM; | |
405 | return 0; | |
406 | } | |
407 | ||
408 | static inline void mm_free_pgd(struct mm_struct * mm) | |
409 | { | |
5e541973 | 410 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
411 | } |
412 | #else | |
413 | #define dup_mmap(mm, oldmm) (0) | |
414 | #define mm_alloc_pgd(mm) (0) | |
415 | #define mm_free_pgd(mm) | |
416 | #endif /* CONFIG_MMU */ | |
417 | ||
23ff4440 | 418 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 419 | |
e94b1766 | 420 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
421 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
422 | ||
4cb0e11b HK |
423 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
424 | ||
425 | static int __init coredump_filter_setup(char *s) | |
426 | { | |
427 | default_dump_filter = | |
428 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
429 | MMF_DUMP_FILTER_MASK; | |
430 | return 1; | |
431 | } | |
432 | ||
433 | __setup("coredump_filter=", coredump_filter_setup); | |
434 | ||
1da177e4 LT |
435 | #include <linux/init_task.h> |
436 | ||
858f0993 AD |
437 | static void mm_init_aio(struct mm_struct *mm) |
438 | { | |
439 | #ifdef CONFIG_AIO | |
440 | spin_lock_init(&mm->ioctx_lock); | |
441 | INIT_HLIST_HEAD(&mm->ioctx_list); | |
442 | #endif | |
443 | } | |
444 | ||
78fb7466 | 445 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
446 | { |
447 | atomic_set(&mm->mm_users, 1); | |
448 | atomic_set(&mm->mm_count, 1); | |
449 | init_rwsem(&mm->mmap_sem); | |
450 | INIT_LIST_HEAD(&mm->mmlist); | |
f8af4da3 HD |
451 | mm->flags = (current->mm) ? |
452 | (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; | |
999d9fc1 | 453 | mm->core_state = NULL; |
1da177e4 | 454 | mm->nr_ptes = 0; |
4294621f | 455 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 456 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 | 457 | spin_lock_init(&mm->page_table_lock); |
1da177e4 | 458 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 459 | mm->cached_hole_size = ~0UL; |
858f0993 | 460 | mm_init_aio(mm); |
cf475ad2 | 461 | mm_init_owner(mm, p); |
1da177e4 LT |
462 | |
463 | if (likely(!mm_alloc_pgd(mm))) { | |
464 | mm->def_flags = 0; | |
cddb8a5c | 465 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
466 | return mm; |
467 | } | |
78fb7466 | 468 | |
1da177e4 LT |
469 | free_mm(mm); |
470 | return NULL; | |
471 | } | |
472 | ||
473 | /* | |
474 | * Allocate and initialize an mm_struct. | |
475 | */ | |
476 | struct mm_struct * mm_alloc(void) | |
477 | { | |
478 | struct mm_struct * mm; | |
479 | ||
480 | mm = allocate_mm(); | |
481 | if (mm) { | |
482 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 483 | mm = mm_init(mm, current); |
1da177e4 LT |
484 | } |
485 | return mm; | |
486 | } | |
487 | ||
488 | /* | |
489 | * Called when the last reference to the mm | |
490 | * is dropped: either by a lazy thread or by | |
491 | * mmput. Free the page directory and the mm. | |
492 | */ | |
7ad5b3a5 | 493 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
494 | { |
495 | BUG_ON(mm == &init_mm); | |
496 | mm_free_pgd(mm); | |
497 | destroy_context(mm); | |
cddb8a5c | 498 | mmu_notifier_mm_destroy(mm); |
1da177e4 LT |
499 | free_mm(mm); |
500 | } | |
6d4e4c4f | 501 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
502 | |
503 | /* | |
504 | * Decrement the use count and release all resources for an mm. | |
505 | */ | |
506 | void mmput(struct mm_struct *mm) | |
507 | { | |
0ae26f1b AM |
508 | might_sleep(); |
509 | ||
1da177e4 LT |
510 | if (atomic_dec_and_test(&mm->mm_users)) { |
511 | exit_aio(mm); | |
1c2fb7a4 | 512 | ksm_exit(mm); |
1da177e4 | 513 | exit_mmap(mm); |
925d1c40 | 514 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
515 | if (!list_empty(&mm->mmlist)) { |
516 | spin_lock(&mmlist_lock); | |
517 | list_del(&mm->mmlist); | |
518 | spin_unlock(&mmlist_lock); | |
519 | } | |
520 | put_swap_token(mm); | |
801460d0 HS |
521 | if (mm->binfmt) |
522 | module_put(mm->binfmt->module); | |
1da177e4 LT |
523 | mmdrop(mm); |
524 | } | |
525 | } | |
526 | EXPORT_SYMBOL_GPL(mmput); | |
527 | ||
528 | /** | |
529 | * get_task_mm - acquire a reference to the task's mm | |
530 | * | |
246bb0b1 | 531 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
532 | * this kernel workthread has transiently adopted a user mm with use_mm, |
533 | * to do its AIO) is not set and if so returns a reference to it, after | |
534 | * bumping up the use count. User must release the mm via mmput() | |
535 | * after use. Typically used by /proc and ptrace. | |
536 | */ | |
537 | struct mm_struct *get_task_mm(struct task_struct *task) | |
538 | { | |
539 | struct mm_struct *mm; | |
540 | ||
541 | task_lock(task); | |
542 | mm = task->mm; | |
543 | if (mm) { | |
246bb0b1 | 544 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
545 | mm = NULL; |
546 | else | |
547 | atomic_inc(&mm->mm_users); | |
548 | } | |
549 | task_unlock(task); | |
550 | return mm; | |
551 | } | |
552 | EXPORT_SYMBOL_GPL(get_task_mm); | |
553 | ||
554 | /* Please note the differences between mmput and mm_release. | |
555 | * mmput is called whenever we stop holding onto a mm_struct, | |
556 | * error success whatever. | |
557 | * | |
558 | * mm_release is called after a mm_struct has been removed | |
559 | * from the current process. | |
560 | * | |
561 | * This difference is important for error handling, when we | |
562 | * only half set up a mm_struct for a new process and need to restore | |
563 | * the old one. Because we mmput the new mm_struct before | |
564 | * restoring the old one. . . | |
565 | * Eric Biederman 10 January 1998 | |
566 | */ | |
567 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
568 | { | |
569 | struct completion *vfork_done = tsk->vfork_done; | |
570 | ||
8141c7f3 LT |
571 | /* Get rid of any futexes when releasing the mm */ |
572 | #ifdef CONFIG_FUTEX | |
573 | if (unlikely(tsk->robust_list)) | |
574 | exit_robust_list(tsk); | |
575 | #ifdef CONFIG_COMPAT | |
576 | if (unlikely(tsk->compat_robust_list)) | |
577 | compat_exit_robust_list(tsk); | |
578 | #endif | |
579 | #endif | |
580 | ||
1da177e4 LT |
581 | /* Get rid of any cached register state */ |
582 | deactivate_mm(tsk, mm); | |
583 | ||
584 | /* notify parent sleeping on vfork() */ | |
585 | if (vfork_done) { | |
586 | tsk->vfork_done = NULL; | |
587 | complete(vfork_done); | |
588 | } | |
fec1d011 RM |
589 | |
590 | /* | |
591 | * If we're exiting normally, clear a user-space tid field if | |
592 | * requested. We leave this alone when dying by signal, to leave | |
593 | * the value intact in a core dump, and to save the unnecessary | |
594 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
595 | */ | |
9c8a8228 ED |
596 | if (tsk->clear_child_tid) { |
597 | if (!(tsk->flags & PF_SIGNALED) && | |
598 | atomic_read(&mm->mm_users) > 1) { | |
599 | /* | |
600 | * We don't check the error code - if userspace has | |
601 | * not set up a proper pointer then tough luck. | |
602 | */ | |
603 | put_user(0, tsk->clear_child_tid); | |
604 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
605 | 1, NULL, NULL, 0); | |
606 | } | |
1da177e4 | 607 | tsk->clear_child_tid = NULL; |
1da177e4 LT |
608 | } |
609 | } | |
610 | ||
a0a7ec30 JD |
611 | /* |
612 | * Allocate a new mm structure and copy contents from the | |
613 | * mm structure of the passed in task structure. | |
614 | */ | |
402b0862 | 615 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
616 | { |
617 | struct mm_struct *mm, *oldmm = current->mm; | |
618 | int err; | |
619 | ||
620 | if (!oldmm) | |
621 | return NULL; | |
622 | ||
623 | mm = allocate_mm(); | |
624 | if (!mm) | |
625 | goto fail_nomem; | |
626 | ||
627 | memcpy(mm, oldmm, sizeof(*mm)); | |
628 | ||
7602bdf2 AC |
629 | /* Initializing for Swap token stuff */ |
630 | mm->token_priority = 0; | |
631 | mm->last_interval = 0; | |
632 | ||
78fb7466 | 633 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
634 | goto fail_nomem; |
635 | ||
636 | if (init_new_context(tsk, mm)) | |
637 | goto fail_nocontext; | |
638 | ||
925d1c40 MH |
639 | dup_mm_exe_file(oldmm, mm); |
640 | ||
a0a7ec30 JD |
641 | err = dup_mmap(mm, oldmm); |
642 | if (err) | |
643 | goto free_pt; | |
644 | ||
645 | mm->hiwater_rss = get_mm_rss(mm); | |
646 | mm->hiwater_vm = mm->total_vm; | |
647 | ||
801460d0 HS |
648 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
649 | goto free_pt; | |
650 | ||
a0a7ec30 JD |
651 | return mm; |
652 | ||
653 | free_pt: | |
801460d0 HS |
654 | /* don't put binfmt in mmput, we haven't got module yet */ |
655 | mm->binfmt = NULL; | |
a0a7ec30 JD |
656 | mmput(mm); |
657 | ||
658 | fail_nomem: | |
659 | return NULL; | |
660 | ||
661 | fail_nocontext: | |
662 | /* | |
663 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
664 | * because it calls destroy_context() | |
665 | */ | |
666 | mm_free_pgd(mm); | |
667 | free_mm(mm); | |
668 | return NULL; | |
669 | } | |
670 | ||
1da177e4 LT |
671 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
672 | { | |
673 | struct mm_struct * mm, *oldmm; | |
674 | int retval; | |
675 | ||
676 | tsk->min_flt = tsk->maj_flt = 0; | |
677 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
678 | #ifdef CONFIG_DETECT_HUNG_TASK |
679 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
680 | #endif | |
1da177e4 LT |
681 | |
682 | tsk->mm = NULL; | |
683 | tsk->active_mm = NULL; | |
684 | ||
685 | /* | |
686 | * Are we cloning a kernel thread? | |
687 | * | |
688 | * We need to steal a active VM for that.. | |
689 | */ | |
690 | oldmm = current->mm; | |
691 | if (!oldmm) | |
692 | return 0; | |
693 | ||
694 | if (clone_flags & CLONE_VM) { | |
695 | atomic_inc(&oldmm->mm_users); | |
696 | mm = oldmm; | |
1da177e4 LT |
697 | goto good_mm; |
698 | } | |
699 | ||
700 | retval = -ENOMEM; | |
a0a7ec30 | 701 | mm = dup_mm(tsk); |
1da177e4 LT |
702 | if (!mm) |
703 | goto fail_nomem; | |
704 | ||
1da177e4 | 705 | good_mm: |
7602bdf2 AC |
706 | /* Initializing for Swap token stuff */ |
707 | mm->token_priority = 0; | |
708 | mm->last_interval = 0; | |
709 | ||
1da177e4 LT |
710 | tsk->mm = mm; |
711 | tsk->active_mm = mm; | |
712 | return 0; | |
713 | ||
1da177e4 LT |
714 | fail_nomem: |
715 | return retval; | |
1da177e4 LT |
716 | } |
717 | ||
a39bc516 | 718 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 719 | { |
498052bb | 720 | struct fs_struct *fs = current->fs; |
1da177e4 | 721 | if (clone_flags & CLONE_FS) { |
498052bb AV |
722 | /* tsk->fs is already what we want */ |
723 | write_lock(&fs->lock); | |
724 | if (fs->in_exec) { | |
725 | write_unlock(&fs->lock); | |
726 | return -EAGAIN; | |
727 | } | |
728 | fs->users++; | |
729 | write_unlock(&fs->lock); | |
1da177e4 LT |
730 | return 0; |
731 | } | |
498052bb | 732 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
733 | if (!tsk->fs) |
734 | return -ENOMEM; | |
735 | return 0; | |
736 | } | |
737 | ||
a016f338 JD |
738 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
739 | { | |
740 | struct files_struct *oldf, *newf; | |
741 | int error = 0; | |
742 | ||
743 | /* | |
744 | * A background process may not have any files ... | |
745 | */ | |
746 | oldf = current->files; | |
747 | if (!oldf) | |
748 | goto out; | |
749 | ||
750 | if (clone_flags & CLONE_FILES) { | |
751 | atomic_inc(&oldf->count); | |
752 | goto out; | |
753 | } | |
754 | ||
a016f338 JD |
755 | newf = dup_fd(oldf, &error); |
756 | if (!newf) | |
757 | goto out; | |
758 | ||
759 | tsk->files = newf; | |
760 | error = 0; | |
761 | out: | |
762 | return error; | |
763 | } | |
764 | ||
fadad878 | 765 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
766 | { |
767 | #ifdef CONFIG_BLOCK | |
768 | struct io_context *ioc = current->io_context; | |
769 | ||
770 | if (!ioc) | |
771 | return 0; | |
fadad878 JA |
772 | /* |
773 | * Share io context with parent, if CLONE_IO is set | |
774 | */ | |
775 | if (clone_flags & CLONE_IO) { | |
776 | tsk->io_context = ioc_task_link(ioc); | |
777 | if (unlikely(!tsk->io_context)) | |
778 | return -ENOMEM; | |
779 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
780 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
781 | if (unlikely(!tsk->io_context)) | |
782 | return -ENOMEM; | |
783 | ||
fd0928df JA |
784 | tsk->io_context->ioprio = ioc->ioprio; |
785 | } | |
786 | #endif | |
787 | return 0; | |
788 | } | |
789 | ||
a39bc516 | 790 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
791 | { |
792 | struct sighand_struct *sig; | |
793 | ||
60348802 | 794 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
795 | atomic_inc(¤t->sighand->count); |
796 | return 0; | |
797 | } | |
798 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 799 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
800 | if (!sig) |
801 | return -ENOMEM; | |
1da177e4 LT |
802 | atomic_set(&sig->count, 1); |
803 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
804 | return 0; | |
805 | } | |
806 | ||
a7e5328a | 807 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 808 | { |
c81addc9 ON |
809 | if (atomic_dec_and_test(&sighand->count)) |
810 | kmem_cache_free(sighand_cachep, sighand); | |
811 | } | |
812 | ||
f06febc9 FM |
813 | |
814 | /* | |
815 | * Initialize POSIX timer handling for a thread group. | |
816 | */ | |
817 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
818 | { | |
819 | /* Thread group counters. */ | |
820 | thread_group_cputime_init(sig); | |
821 | ||
822 | /* Expiration times and increments. */ | |
42c4ab41 SG |
823 | sig->it[CPUCLOCK_PROF].expires = cputime_zero; |
824 | sig->it[CPUCLOCK_PROF].incr = cputime_zero; | |
825 | sig->it[CPUCLOCK_VIRT].expires = cputime_zero; | |
826 | sig->it[CPUCLOCK_VIRT].incr = cputime_zero; | |
f06febc9 FM |
827 | |
828 | /* Cached expiration times. */ | |
829 | sig->cputime_expires.prof_exp = cputime_zero; | |
830 | sig->cputime_expires.virt_exp = cputime_zero; | |
831 | sig->cputime_expires.sched_exp = 0; | |
832 | ||
6279a751 ON |
833 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { |
834 | sig->cputime_expires.prof_exp = | |
835 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
836 | sig->cputimer.running = 1; | |
837 | } | |
838 | ||
f06febc9 FM |
839 | /* The timer lists. */ |
840 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
841 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
842 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
843 | } | |
844 | ||
a39bc516 | 845 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
846 | { |
847 | struct signal_struct *sig; | |
1da177e4 | 848 | |
4ab6c083 | 849 | if (clone_flags & CLONE_THREAD) |
490dea45 | 850 | return 0; |
490dea45 | 851 | |
6279a751 | 852 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
853 | tsk->signal = sig; |
854 | if (!sig) | |
855 | return -ENOMEM; | |
856 | ||
1da177e4 LT |
857 | atomic_set(&sig->count, 1); |
858 | atomic_set(&sig->live, 1); | |
859 | init_waitqueue_head(&sig->wait_chldexit); | |
860 | sig->flags = 0; | |
b3bfa0cb SB |
861 | if (clone_flags & CLONE_NEWPID) |
862 | sig->flags |= SIGNAL_UNKILLABLE; | |
1da177e4 LT |
863 | sig->group_exit_code = 0; |
864 | sig->group_exit_task = NULL; | |
865 | sig->group_stop_count = 0; | |
db51aecc | 866 | sig->curr_target = tsk; |
1da177e4 LT |
867 | init_sigpending(&sig->shared_pending); |
868 | INIT_LIST_HEAD(&sig->posix_timers); | |
869 | ||
c9cb2e3d | 870 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 871 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 872 | sig->real_timer.function = it_real_fn; |
1da177e4 | 873 | |
1da177e4 | 874 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 875 | sig->tty_old_pgrp = NULL; |
9c9f4ded | 876 | sig->tty = NULL; |
1da177e4 | 877 | |
32bd671d | 878 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; |
9ac52315 LV |
879 | sig->gtime = cputime_zero; |
880 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
881 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
882 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 883 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
1f10206c | 884 | sig->maxrss = sig->cmaxrss = 0; |
5995477a | 885 | task_io_accounting_init(&sig->ioac); |
32bd671d | 886 | sig->sum_sched_runtime = 0; |
ad4ecbcb | 887 | taskstats_tgid_init(sig); |
1da177e4 LT |
888 | |
889 | task_lock(current->group_leader); | |
890 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
891 | task_unlock(current->group_leader); | |
892 | ||
6279a751 ON |
893 | posix_cpu_timers_init_group(sig); |
894 | ||
0e464814 | 895 | acct_init_pacct(&sig->pacct); |
1da177e4 | 896 | |
522ed776 MT |
897 | tty_audit_fork(sig); |
898 | ||
28b83c51 KM |
899 | sig->oom_adj = current->signal->oom_adj; |
900 | ||
1da177e4 LT |
901 | return 0; |
902 | } | |
903 | ||
6b3934ef ON |
904 | void __cleanup_signal(struct signal_struct *sig) |
905 | { | |
f06febc9 | 906 | thread_group_cputime_free(sig); |
9c9f4ded | 907 | tty_kref_put(sig->tty); |
6b3934ef ON |
908 | kmem_cache_free(signal_cachep, sig); |
909 | } | |
910 | ||
a39bc516 | 911 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
912 | { |
913 | unsigned long new_flags = p->flags; | |
914 | ||
83144186 | 915 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 | 916 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 917 | new_flags |= PF_STARTING; |
1da177e4 | 918 | p->flags = new_flags; |
2e131895 | 919 | clear_freeze_flag(p); |
1da177e4 LT |
920 | } |
921 | ||
17da2bd9 | 922 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
923 | { |
924 | current->clear_child_tid = tidptr; | |
925 | ||
b488893a | 926 | return task_pid_vnr(current); |
1da177e4 LT |
927 | } |
928 | ||
a39bc516 | 929 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 930 | { |
23f78d4a | 931 | spin_lock_init(&p->pi_lock); |
e29e175b | 932 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
933 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
934 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
935 | #endif |
936 | } | |
937 | ||
cf475ad2 BS |
938 | #ifdef CONFIG_MM_OWNER |
939 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
940 | { | |
941 | mm->owner = p; | |
942 | } | |
943 | #endif /* CONFIG_MM_OWNER */ | |
944 | ||
f06febc9 FM |
945 | /* |
946 | * Initialize POSIX timer handling for a single task. | |
947 | */ | |
948 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
949 | { | |
950 | tsk->cputime_expires.prof_exp = cputime_zero; | |
951 | tsk->cputime_expires.virt_exp = cputime_zero; | |
952 | tsk->cputime_expires.sched_exp = 0; | |
953 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
954 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
955 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
956 | } | |
957 | ||
1da177e4 LT |
958 | /* |
959 | * This creates a new process as a copy of the old one, | |
960 | * but does not actually start it yet. | |
961 | * | |
962 | * It copies the registers, and all the appropriate | |
963 | * parts of the process environment (as per the clone | |
964 | * flags). The actual kick-off is left to the caller. | |
965 | */ | |
36c8b586 IM |
966 | static struct task_struct *copy_process(unsigned long clone_flags, |
967 | unsigned long stack_start, | |
968 | struct pt_regs *regs, | |
969 | unsigned long stack_size, | |
36c8b586 | 970 | int __user *child_tidptr, |
09a05394 RM |
971 | struct pid *pid, |
972 | int trace) | |
1da177e4 LT |
973 | { |
974 | int retval; | |
a24efe62 | 975 | struct task_struct *p; |
b4f48b63 | 976 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
977 | |
978 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
979 | return ERR_PTR(-EINVAL); | |
980 | ||
981 | /* | |
982 | * Thread groups must share signals as well, and detached threads | |
983 | * can only be started up within the thread group. | |
984 | */ | |
985 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
986 | return ERR_PTR(-EINVAL); | |
987 | ||
988 | /* | |
989 | * Shared signal handlers imply shared VM. By way of the above, | |
990 | * thread groups also imply shared VM. Blocking this case allows | |
991 | * for various simplifications in other code. | |
992 | */ | |
993 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
994 | return ERR_PTR(-EINVAL); | |
995 | ||
123be07b SB |
996 | /* |
997 | * Siblings of global init remain as zombies on exit since they are | |
998 | * not reaped by their parent (swapper). To solve this and to avoid | |
999 | * multi-rooted process trees, prevent global and container-inits | |
1000 | * from creating siblings. | |
1001 | */ | |
1002 | if ((clone_flags & CLONE_PARENT) && | |
1003 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1004 | return ERR_PTR(-EINVAL); | |
1005 | ||
1da177e4 LT |
1006 | retval = security_task_create(clone_flags); |
1007 | if (retval) | |
1008 | goto fork_out; | |
1009 | ||
1010 | retval = -ENOMEM; | |
1011 | p = dup_task_struct(current); | |
1012 | if (!p) | |
1013 | goto fork_out; | |
1014 | ||
f7e8b616 SR |
1015 | ftrace_graph_init_task(p); |
1016 | ||
bea493a0 PZ |
1017 | rt_mutex_init_task(p); |
1018 | ||
d12c1a37 | 1019 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1020 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1021 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1022 | #endif | |
1da177e4 | 1023 | retval = -EAGAIN; |
3b11a1de | 1024 | if (atomic_read(&p->real_cred->user->processes) >= |
1da177e4 LT |
1025 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { |
1026 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
18b6e041 | 1027 | p->real_cred->user != INIT_USER) |
1da177e4 LT |
1028 | goto bad_fork_free; |
1029 | } | |
1030 | ||
f1752eec DH |
1031 | retval = copy_creds(p, clone_flags); |
1032 | if (retval < 0) | |
1033 | goto bad_fork_free; | |
1da177e4 LT |
1034 | |
1035 | /* | |
1036 | * If multiple threads are within copy_process(), then this check | |
1037 | * triggers too late. This doesn't hurt, the check is only there | |
1038 | * to stop root fork bombs. | |
1039 | */ | |
04ec93fe | 1040 | retval = -EAGAIN; |
1da177e4 LT |
1041 | if (nr_threads >= max_threads) |
1042 | goto bad_fork_cleanup_count; | |
1043 | ||
a1261f54 | 1044 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1045 | goto bad_fork_cleanup_count; |
1046 | ||
1da177e4 | 1047 | p->did_exec = 0; |
ca74e92b | 1048 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1049 | copy_flags(clone_flags, p); |
1da177e4 LT |
1050 | INIT_LIST_HEAD(&p->children); |
1051 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1052 | rcu_copy_process(p); |
1da177e4 LT |
1053 | p->vfork_done = NULL; |
1054 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1055 | |
1da177e4 LT |
1056 | init_sigpending(&p->pending); |
1057 | ||
1058 | p->utime = cputime_zero; | |
1059 | p->stime = cputime_zero; | |
9ac52315 | 1060 | p->gtime = cputime_zero; |
c66f08be MN |
1061 | p->utimescaled = cputime_zero; |
1062 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 1063 | p->prev_utime = cputime_zero; |
9301899b | 1064 | p->prev_stime = cputime_zero; |
172ba844 | 1065 | |
6976675d AV |
1066 | p->default_timer_slack_ns = current->timer_slack_ns; |
1067 | ||
5995477a | 1068 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1069 | acct_clear_integrals(p); |
1070 | ||
f06febc9 | 1071 | posix_cpu_timers_init(p); |
1da177e4 LT |
1072 | |
1073 | p->lock_depth = -1; /* -1 = no lock */ | |
1074 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1075 | p->real_start_time = p->start_time; |
1076 | monotonic_to_bootbased(&p->real_start_time); | |
1da177e4 | 1077 | p->io_context = NULL; |
1da177e4 | 1078 | p->audit_context = NULL; |
b4f48b63 | 1079 | cgroup_fork(p); |
1da177e4 | 1080 | #ifdef CONFIG_NUMA |
846a16bf | 1081 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1082 | if (IS_ERR(p->mempolicy)) { |
1083 | retval = PTR_ERR(p->mempolicy); | |
1084 | p->mempolicy = NULL; | |
b4f48b63 | 1085 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1086 | } |
c61afb18 | 1087 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1088 | #endif |
de30a2b3 IM |
1089 | #ifdef CONFIG_TRACE_IRQFLAGS |
1090 | p->irq_events = 0; | |
b36e4758 RK |
1091 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1092 | p->hardirqs_enabled = 1; | |
1093 | #else | |
de30a2b3 | 1094 | p->hardirqs_enabled = 0; |
b36e4758 | 1095 | #endif |
de30a2b3 IM |
1096 | p->hardirq_enable_ip = 0; |
1097 | p->hardirq_enable_event = 0; | |
1098 | p->hardirq_disable_ip = _THIS_IP_; | |
1099 | p->hardirq_disable_event = 0; | |
1100 | p->softirqs_enabled = 1; | |
1101 | p->softirq_enable_ip = _THIS_IP_; | |
1102 | p->softirq_enable_event = 0; | |
1103 | p->softirq_disable_ip = 0; | |
1104 | p->softirq_disable_event = 0; | |
1105 | p->hardirq_context = 0; | |
1106 | p->softirq_context = 0; | |
1107 | #endif | |
fbb9ce95 IM |
1108 | #ifdef CONFIG_LOCKDEP |
1109 | p->lockdep_depth = 0; /* no locks held yet */ | |
1110 | p->curr_chain_key = 0; | |
1111 | p->lockdep_recursion = 0; | |
1112 | #endif | |
1da177e4 | 1113 | |
408894ee IM |
1114 | #ifdef CONFIG_DEBUG_MUTEXES |
1115 | p->blocked_on = NULL; /* not blocked yet */ | |
1116 | #endif | |
0f481406 MM |
1117 | |
1118 | p->bts = NULL; | |
408894ee | 1119 | |
d899bf7b SS |
1120 | p->stack_start = stack_start; |
1121 | ||
3c90e6e9 SV |
1122 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1123 | sched_fork(p, clone_flags); | |
6ab423e0 | 1124 | |
cdd6c482 | 1125 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1126 | if (retval) |
1127 | goto bad_fork_cleanup_policy; | |
3c90e6e9 | 1128 | |
1da177e4 | 1129 | if ((retval = audit_alloc(p))) |
f1752eec | 1130 | goto bad_fork_cleanup_policy; |
1da177e4 LT |
1131 | /* copy all the process information */ |
1132 | if ((retval = copy_semundo(clone_flags, p))) | |
1133 | goto bad_fork_cleanup_audit; | |
1134 | if ((retval = copy_files(clone_flags, p))) | |
1135 | goto bad_fork_cleanup_semundo; | |
1136 | if ((retval = copy_fs(clone_flags, p))) | |
1137 | goto bad_fork_cleanup_files; | |
1138 | if ((retval = copy_sighand(clone_flags, p))) | |
1139 | goto bad_fork_cleanup_fs; | |
1140 | if ((retval = copy_signal(clone_flags, p))) | |
1141 | goto bad_fork_cleanup_sighand; | |
1142 | if ((retval = copy_mm(clone_flags, p))) | |
1143 | goto bad_fork_cleanup_signal; | |
ab516013 | 1144 | if ((retval = copy_namespaces(clone_flags, p))) |
d84f4f99 | 1145 | goto bad_fork_cleanup_mm; |
fadad878 | 1146 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1147 | goto bad_fork_cleanup_namespaces; |
6f2c55b8 | 1148 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
1da177e4 | 1149 | if (retval) |
fd0928df | 1150 | goto bad_fork_cleanup_io; |
1da177e4 | 1151 | |
425fb2b4 PE |
1152 | if (pid != &init_struct_pid) { |
1153 | retval = -ENOMEM; | |
61bce0f1 | 1154 | pid = alloc_pid(p->nsproxy->pid_ns); |
425fb2b4 | 1155 | if (!pid) |
fd0928df | 1156 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1157 | |
1158 | if (clone_flags & CLONE_NEWPID) { | |
61bce0f1 | 1159 | retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); |
6f4e6433 PE |
1160 | if (retval < 0) |
1161 | goto bad_fork_free_pid; | |
1162 | } | |
425fb2b4 PE |
1163 | } |
1164 | ||
1165 | p->pid = pid_nr(pid); | |
1166 | p->tgid = p->pid; | |
1167 | if (clone_flags & CLONE_THREAD) | |
1168 | p->tgid = current->tgid; | |
1169 | ||
e885dcde SH |
1170 | if (current->nsproxy != p->nsproxy) { |
1171 | retval = ns_cgroup_clone(p, pid); | |
1172 | if (retval) | |
f7e8b616 | 1173 | goto bad_fork_free_pid; |
e885dcde SH |
1174 | } |
1175 | ||
1da177e4 LT |
1176 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1177 | /* | |
1178 | * Clear TID on mm_release()? | |
1179 | */ | |
1180 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1181 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1182 | p->robust_list = NULL; |
1183 | #ifdef CONFIG_COMPAT | |
1184 | p->compat_robust_list = NULL; | |
1185 | #endif | |
c87e2837 IM |
1186 | INIT_LIST_HEAD(&p->pi_state_list); |
1187 | p->pi_state_cache = NULL; | |
42b2dd0a | 1188 | #endif |
f9a3879a GM |
1189 | /* |
1190 | * sigaltstack should be cleared when sharing the same VM | |
1191 | */ | |
1192 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1193 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1194 | ||
1da177e4 LT |
1195 | /* |
1196 | * Syscall tracing should be turned off in the child regardless | |
1197 | * of CLONE_PTRACE. | |
1198 | */ | |
1199 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1200 | #ifdef TIF_SYSCALL_EMU |
1201 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1202 | #endif | |
9745512c | 1203 | clear_all_latency_tracing(p); |
1da177e4 | 1204 | |
1da177e4 LT |
1205 | /* ok, now we should be set up.. */ |
1206 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1207 | p->pdeath_signal = 0; | |
1208 | p->exit_state = 0; | |
1209 | ||
1da177e4 LT |
1210 | /* |
1211 | * Ok, make it visible to the rest of the system. | |
1212 | * We dont wake it up yet. | |
1213 | */ | |
1214 | p->group_leader = p; | |
47e65328 | 1215 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1216 | |
b4f48b63 PM |
1217 | /* Now that the task is set up, run cgroup callbacks if |
1218 | * necessary. We need to run them before the task is visible | |
1219 | * on the tasklist. */ | |
1220 | cgroup_fork_callbacks(p); | |
1221 | cgroup_callbacks_done = 1; | |
1222 | ||
1da177e4 LT |
1223 | /* Need tasklist lock for parent etc handling! */ |
1224 | write_lock_irq(&tasklist_lock); | |
1225 | ||
1226 | /* | |
476d139c NP |
1227 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1228 | * not be changed, nor will its assigned CPU. | |
1229 | * | |
1230 | * The cpus_allowed mask of the parent may have changed after it was | |
1231 | * copied first time - so re-copy it here, then check the child's CPU | |
1232 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1233 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1234 | */ |
1235 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1236 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1237 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1238 | !cpu_online(task_cpu(p)))) | |
476d139c | 1239 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1240 | |
1da177e4 | 1241 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1242 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1243 | p->real_parent = current->real_parent; |
2d5516cb ON |
1244 | p->parent_exec_id = current->parent_exec_id; |
1245 | } else { | |
1da177e4 | 1246 | p->real_parent = current; |
2d5516cb ON |
1247 | p->parent_exec_id = current->self_exec_id; |
1248 | } | |
1da177e4 | 1249 | |
3f17da69 | 1250 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1251 | |
1252 | /* | |
1253 | * Process group and session signals need to be delivered to just the | |
1254 | * parent before the fork or both the parent and the child after the | |
1255 | * fork. Restart if a signal comes in before we add the new process to | |
1256 | * it's process group. | |
1257 | * A fatal signal pending means that current will exit, so the new | |
1258 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1259 | */ | |
23ff4440 | 1260 | recalc_sigpending(); |
4a2c7a78 ON |
1261 | if (signal_pending(current)) { |
1262 | spin_unlock(¤t->sighand->siglock); | |
1263 | write_unlock_irq(&tasklist_lock); | |
1264 | retval = -ERESTARTNOINTR; | |
f7e8b616 | 1265 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1266 | } |
1267 | ||
1da177e4 | 1268 | if (clone_flags & CLONE_THREAD) { |
4ab6c083 ON |
1269 | atomic_inc(¤t->signal->count); |
1270 | atomic_inc(¤t->signal->live); | |
1da177e4 | 1271 | p->group_leader = current->group_leader; |
47e65328 | 1272 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 LT |
1273 | } |
1274 | ||
73b9ebfe | 1275 | if (likely(p->pid)) { |
f470021a | 1276 | list_add_tail(&p->sibling, &p->real_parent->children); |
09a05394 | 1277 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1278 | |
1279 | if (thread_group_leader(p)) { | |
5cd17569 | 1280 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1281 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1282 | |
fea9d175 | 1283 | p->signal->leader_pid = pid; |
9c9f4ded AC |
1284 | tty_kref_put(p->signal->tty); |
1285 | p->signal->tty = tty_kref_get(current->signal->tty); | |
5cd17569 EB |
1286 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1287 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1288 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1289 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1290 | } |
85868995 | 1291 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1292 | nr_threads++; |
1da177e4 LT |
1293 | } |
1294 | ||
1da177e4 | 1295 | total_forks++; |
3f17da69 | 1296 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1297 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1298 | proc_fork_connector(p); |
817929ec | 1299 | cgroup_post_fork(p); |
cdd6c482 | 1300 | perf_event_fork(p); |
1da177e4 LT |
1301 | return p; |
1302 | ||
425fb2b4 PE |
1303 | bad_fork_free_pid: |
1304 | if (pid != &init_struct_pid) | |
1305 | free_pid(pid); | |
fd0928df JA |
1306 | bad_fork_cleanup_io: |
1307 | put_io_context(p->io_context); | |
ab516013 | 1308 | bad_fork_cleanup_namespaces: |
444f378b | 1309 | exit_task_namespaces(p); |
1da177e4 LT |
1310 | bad_fork_cleanup_mm: |
1311 | if (p->mm) | |
1312 | mmput(p->mm); | |
1313 | bad_fork_cleanup_signal: | |
4ab6c083 ON |
1314 | if (!(clone_flags & CLONE_THREAD)) |
1315 | __cleanup_signal(p->signal); | |
1da177e4 | 1316 | bad_fork_cleanup_sighand: |
a7e5328a | 1317 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1318 | bad_fork_cleanup_fs: |
1319 | exit_fs(p); /* blocking */ | |
1320 | bad_fork_cleanup_files: | |
1321 | exit_files(p); /* blocking */ | |
1322 | bad_fork_cleanup_semundo: | |
1323 | exit_sem(p); | |
1324 | bad_fork_cleanup_audit: | |
1325 | audit_free(p); | |
1da177e4 | 1326 | bad_fork_cleanup_policy: |
cdd6c482 | 1327 | perf_event_free_task(p); |
1da177e4 | 1328 | #ifdef CONFIG_NUMA |
f0be3d32 | 1329 | mpol_put(p->mempolicy); |
b4f48b63 | 1330 | bad_fork_cleanup_cgroup: |
1da177e4 | 1331 | #endif |
b4f48b63 | 1332 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1333 | delayacct_tsk_free(p); |
a1261f54 | 1334 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 | 1335 | bad_fork_cleanup_count: |
d84f4f99 | 1336 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1337 | exit_creds(p); |
1da177e4 LT |
1338 | bad_fork_free: |
1339 | free_task(p); | |
fe7d37d1 ON |
1340 | fork_out: |
1341 | return ERR_PTR(retval); | |
1da177e4 LT |
1342 | } |
1343 | ||
6b2fb3c6 | 1344 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1345 | { |
1346 | memset(regs, 0, sizeof(struct pt_regs)); | |
1347 | return regs; | |
1348 | } | |
1349 | ||
9abcf40b | 1350 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1351 | { |
36c8b586 | 1352 | struct task_struct *task; |
1da177e4 LT |
1353 | struct pt_regs regs; |
1354 | ||
30e49c26 | 1355 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1356 | &init_struct_pid, 0); |
753ca4f3 AM |
1357 | if (!IS_ERR(task)) |
1358 | init_idle(task, cpu); | |
73b9ebfe | 1359 | |
1da177e4 LT |
1360 | return task; |
1361 | } | |
1362 | ||
1da177e4 LT |
1363 | /* |
1364 | * Ok, this is the main fork-routine. | |
1365 | * | |
1366 | * It copies the process, and if successful kick-starts | |
1367 | * it and waits for it to finish using the VM if required. | |
1368 | */ | |
1369 | long do_fork(unsigned long clone_flags, | |
1370 | unsigned long stack_start, | |
1371 | struct pt_regs *regs, | |
1372 | unsigned long stack_size, | |
1373 | int __user *parent_tidptr, | |
1374 | int __user *child_tidptr) | |
1375 | { | |
1376 | struct task_struct *p; | |
1377 | int trace = 0; | |
92476d7f | 1378 | long nr; |
1da177e4 | 1379 | |
18b6e041 SH |
1380 | /* |
1381 | * Do some preliminary argument and permissions checking before we | |
1382 | * actually start allocating stuff | |
1383 | */ | |
1384 | if (clone_flags & CLONE_NEWUSER) { | |
1385 | if (clone_flags & CLONE_THREAD) | |
1386 | return -EINVAL; | |
1387 | /* hopefully this check will go away when userns support is | |
1388 | * complete | |
1389 | */ | |
7657d904 SH |
1390 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
1391 | !capable(CAP_SETGID)) | |
18b6e041 SH |
1392 | return -EPERM; |
1393 | } | |
1394 | ||
bdff746a AM |
1395 | /* |
1396 | * We hope to recycle these flags after 2.6.26 | |
1397 | */ | |
1398 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1399 | static int __read_mostly count = 100; | |
1400 | ||
1401 | if (count > 0 && printk_ratelimit()) { | |
1402 | char comm[TASK_COMM_LEN]; | |
1403 | ||
1404 | count--; | |
1405 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1406 | "clone flags 0x%lx\n", | |
1407 | get_task_comm(comm, current), | |
1408 | clone_flags & CLONE_STOPPED); | |
1409 | } | |
1410 | } | |
1411 | ||
09a05394 RM |
1412 | /* |
1413 | * When called from kernel_thread, don't do user tracing stuff. | |
1414 | */ | |
1415 | if (likely(user_mode(regs))) | |
1416 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1417 | |
a6f5e063 | 1418 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1419 | child_tidptr, NULL, trace); |
1da177e4 LT |
1420 | /* |
1421 | * Do this prior waking up the new thread - the thread pointer | |
1422 | * might get invalid after that point, if the thread exits quickly. | |
1423 | */ | |
1424 | if (!IS_ERR(p)) { | |
1425 | struct completion vfork; | |
1426 | ||
0a16b607 MD |
1427 | trace_sched_process_fork(current, p); |
1428 | ||
6c5f3e7b | 1429 | nr = task_pid_vnr(p); |
30e49c26 PE |
1430 | |
1431 | if (clone_flags & CLONE_PARENT_SETTID) | |
1432 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1433 | |
1da177e4 LT |
1434 | if (clone_flags & CLONE_VFORK) { |
1435 | p->vfork_done = &vfork; | |
1436 | init_completion(&vfork); | |
1437 | } | |
1438 | ||
a64e6494 | 1439 | audit_finish_fork(p); |
087eb437 | 1440 | tracehook_report_clone(regs, clone_flags, nr, p); |
09a05394 RM |
1441 | |
1442 | /* | |
1443 | * We set PF_STARTING at creation in case tracing wants to | |
1444 | * use this to distinguish a fully live task from one that | |
1445 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1446 | * clear it and set the child going. | |
1447 | */ | |
1448 | p->flags &= ~PF_STARTING; | |
1449 | ||
1450 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1da177e4 LT |
1451 | /* |
1452 | * We'll start up with an immediate SIGSTOP. | |
1453 | */ | |
1454 | sigaddset(&p->pending.signal, SIGSTOP); | |
1455 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
d9ae90ac | 1456 | __set_task_state(p, TASK_STOPPED); |
09a05394 RM |
1457 | } else { |
1458 | wake_up_new_task(p, clone_flags); | |
1da177e4 LT |
1459 | } |
1460 | ||
09a05394 RM |
1461 | tracehook_report_clone_complete(trace, regs, |
1462 | clone_flags, nr, p); | |
1463 | ||
1da177e4 | 1464 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1465 | freezer_do_not_count(); |
1da177e4 | 1466 | wait_for_completion(&vfork); |
ba96a0c8 | 1467 | freezer_count(); |
daded34b | 1468 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1469 | } |
1470 | } else { | |
92476d7f | 1471 | nr = PTR_ERR(p); |
1da177e4 | 1472 | } |
92476d7f | 1473 | return nr; |
1da177e4 LT |
1474 | } |
1475 | ||
5fd63b30 RT |
1476 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1477 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1478 | #endif | |
1479 | ||
51cc5068 | 1480 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1481 | { |
1482 | struct sighand_struct *sighand = data; | |
1483 | ||
a35afb83 | 1484 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1485 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1486 | } |
1487 | ||
1da177e4 LT |
1488 | void __init proc_caches_init(void) |
1489 | { | |
1490 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1491 | sizeof(struct sighand_struct), 0, | |
2dff4405 VN |
1492 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
1493 | SLAB_NOTRACK, sighand_ctor); | |
1da177e4 LT |
1494 | signal_cachep = kmem_cache_create("signal_cache", |
1495 | sizeof(struct signal_struct), 0, | |
2dff4405 | 1496 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1497 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 1498 | sizeof(struct files_struct), 0, |
2dff4405 | 1499 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1500 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 1501 | sizeof(struct fs_struct), 0, |
2dff4405 | 1502 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
1da177e4 | 1503 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1504 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
2dff4405 | 1505 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
33e5d769 | 1506 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
8feae131 | 1507 | mmap_init(); |
1da177e4 | 1508 | } |
cf2e340f | 1509 | |
cf2e340f JD |
1510 | /* |
1511 | * Check constraints on flags passed to the unshare system call and | |
1512 | * force unsharing of additional process context as appropriate. | |
1513 | */ | |
a39bc516 | 1514 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1515 | { |
1516 | /* | |
1517 | * If unsharing a thread from a thread group, must also | |
1518 | * unshare vm. | |
1519 | */ | |
1520 | if (*flags_ptr & CLONE_THREAD) | |
1521 | *flags_ptr |= CLONE_VM; | |
1522 | ||
1523 | /* | |
1524 | * If unsharing vm, must also unshare signal handlers. | |
1525 | */ | |
1526 | if (*flags_ptr & CLONE_VM) | |
1527 | *flags_ptr |= CLONE_SIGHAND; | |
1528 | ||
1529 | /* | |
1530 | * If unsharing signal handlers and the task was created | |
1531 | * using CLONE_THREAD, then must unshare the thread | |
1532 | */ | |
1533 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1534 | (atomic_read(¤t->signal->count) > 1)) | |
1535 | *flags_ptr |= CLONE_THREAD; | |
1536 | ||
1537 | /* | |
1538 | * If unsharing namespace, must also unshare filesystem information. | |
1539 | */ | |
1540 | if (*flags_ptr & CLONE_NEWNS) | |
1541 | *flags_ptr |= CLONE_FS; | |
1542 | } | |
1543 | ||
1544 | /* | |
1545 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1546 | */ | |
1547 | static int unshare_thread(unsigned long unshare_flags) | |
1548 | { | |
1549 | if (unshare_flags & CLONE_THREAD) | |
1550 | return -EINVAL; | |
1551 | ||
1552 | return 0; | |
1553 | } | |
1554 | ||
1555 | /* | |
99d1419d | 1556 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1557 | */ |
1558 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1559 | { | |
1560 | struct fs_struct *fs = current->fs; | |
1561 | ||
498052bb AV |
1562 | if (!(unshare_flags & CLONE_FS) || !fs) |
1563 | return 0; | |
1564 | ||
1565 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1566 | if (fs->users == 1) | |
1567 | return 0; | |
1568 | ||
1569 | *new_fsp = copy_fs_struct(fs); | |
1570 | if (!*new_fsp) | |
1571 | return -ENOMEM; | |
cf2e340f JD |
1572 | |
1573 | return 0; | |
1574 | } | |
1575 | ||
cf2e340f | 1576 | /* |
dae3c5a0 | 1577 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1578 | */ |
1579 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1580 | { | |
1581 | struct sighand_struct *sigh = current->sighand; | |
1582 | ||
dae3c5a0 | 1583 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1584 | return -EINVAL; |
1585 | else | |
1586 | return 0; | |
1587 | } | |
1588 | ||
1589 | /* | |
a0a7ec30 | 1590 | * Unshare vm if it is being shared |
cf2e340f JD |
1591 | */ |
1592 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1593 | { | |
1594 | struct mm_struct *mm = current->mm; | |
1595 | ||
1596 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1597 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1598 | return -EINVAL; |
a0a7ec30 | 1599 | } |
cf2e340f JD |
1600 | |
1601 | return 0; | |
cf2e340f JD |
1602 | } |
1603 | ||
1604 | /* | |
a016f338 | 1605 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1606 | */ |
1607 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1608 | { | |
1609 | struct files_struct *fd = current->files; | |
a016f338 | 1610 | int error = 0; |
cf2e340f JD |
1611 | |
1612 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1613 | (fd && atomic_read(&fd->count) > 1)) { |
1614 | *new_fdp = dup_fd(fd, &error); | |
1615 | if (!*new_fdp) | |
1616 | return error; | |
1617 | } | |
cf2e340f JD |
1618 | |
1619 | return 0; | |
1620 | } | |
1621 | ||
cf2e340f JD |
1622 | /* |
1623 | * unshare allows a process to 'unshare' part of the process | |
1624 | * context which was originally shared using clone. copy_* | |
1625 | * functions used by do_fork() cannot be used here directly | |
1626 | * because they modify an inactive task_struct that is being | |
1627 | * constructed. Here we are modifying the current, active, | |
1628 | * task_struct. | |
1629 | */ | |
6559eed8 | 1630 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f JD |
1631 | { |
1632 | int err = 0; | |
1633 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1634 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1635 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1636 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1637 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1638 | int do_sysvsem = 0; |
cf2e340f JD |
1639 | |
1640 | check_unshare_flags(&unshare_flags); | |
1641 | ||
06f9d4f9 EB |
1642 | /* Return -EINVAL for all unsupported flags */ |
1643 | err = -EINVAL; | |
1644 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1645 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
18b6e041 | 1646 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) |
06f9d4f9 EB |
1647 | goto bad_unshare_out; |
1648 | ||
6013f67f MS |
1649 | /* |
1650 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1651 | * to a new ipc namespace, the semaphore arrays from the old | |
1652 | * namespace are unreachable. | |
1653 | */ | |
1654 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1655 | do_sysvsem = 1; |
cf2e340f JD |
1656 | if ((err = unshare_thread(unshare_flags))) |
1657 | goto bad_unshare_out; | |
1658 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1659 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1660 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1661 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1662 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1663 | goto bad_unshare_cleanup_sigh; | |
1664 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1665 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1666 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1667 | new_fs))) | |
9edff4ab | 1668 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1669 | |
9edff4ab MS |
1670 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1671 | if (do_sysvsem) { | |
1672 | /* | |
1673 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1674 | */ | |
1675 | exit_sem(current); | |
1676 | } | |
ab516013 | 1677 | |
c0b2fc31 | 1678 | if (new_nsproxy) { |
cf7b708c PE |
1679 | switch_task_namespaces(current, new_nsproxy); |
1680 | new_nsproxy = NULL; | |
c0b2fc31 | 1681 | } |
cf2e340f | 1682 | |
cf7b708c PE |
1683 | task_lock(current); |
1684 | ||
cf2e340f JD |
1685 | if (new_fs) { |
1686 | fs = current->fs; | |
498052bb | 1687 | write_lock(&fs->lock); |
cf2e340f | 1688 | current->fs = new_fs; |
498052bb AV |
1689 | if (--fs->users) |
1690 | new_fs = NULL; | |
1691 | else | |
1692 | new_fs = fs; | |
1693 | write_unlock(&fs->lock); | |
cf2e340f JD |
1694 | } |
1695 | ||
cf2e340f JD |
1696 | if (new_mm) { |
1697 | mm = current->mm; | |
1698 | active_mm = current->active_mm; | |
1699 | current->mm = new_mm; | |
1700 | current->active_mm = new_mm; | |
1701 | activate_mm(active_mm, new_mm); | |
1702 | new_mm = mm; | |
1703 | } | |
1704 | ||
1705 | if (new_fd) { | |
1706 | fd = current->files; | |
1707 | current->files = new_fd; | |
1708 | new_fd = fd; | |
1709 | } | |
1710 | ||
1711 | task_unlock(current); | |
1712 | } | |
1713 | ||
c0b2fc31 | 1714 | if (new_nsproxy) |
444f378b | 1715 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1716 | |
cf2e340f JD |
1717 | bad_unshare_cleanup_fd: |
1718 | if (new_fd) | |
1719 | put_files_struct(new_fd); | |
1720 | ||
1721 | bad_unshare_cleanup_vm: | |
1722 | if (new_mm) | |
1723 | mmput(new_mm); | |
1724 | ||
1725 | bad_unshare_cleanup_sigh: | |
1726 | if (new_sigh) | |
1727 | if (atomic_dec_and_test(&new_sigh->count)) | |
1728 | kmem_cache_free(sighand_cachep, new_sigh); | |
1729 | ||
cf2e340f JD |
1730 | bad_unshare_cleanup_fs: |
1731 | if (new_fs) | |
498052bb | 1732 | free_fs_struct(new_fs); |
cf2e340f JD |
1733 | |
1734 | bad_unshare_cleanup_thread: | |
1735 | bad_unshare_out: | |
1736 | return err; | |
1737 | } | |
3b125388 AV |
1738 | |
1739 | /* | |
1740 | * Helper to unshare the files of the current task. | |
1741 | * We don't want to expose copy_files internals to | |
1742 | * the exec layer of the kernel. | |
1743 | */ | |
1744 | ||
1745 | int unshare_files(struct files_struct **displaced) | |
1746 | { | |
1747 | struct task_struct *task = current; | |
50704516 | 1748 | struct files_struct *copy = NULL; |
3b125388 AV |
1749 | int error; |
1750 | ||
1751 | error = unshare_fd(CLONE_FILES, ©); | |
1752 | if (error || !copy) { | |
1753 | *displaced = NULL; | |
1754 | return error; | |
1755 | } | |
1756 | *displaced = task->files; | |
1757 | task_lock(task); | |
1758 | task->files = copy; | |
1759 | task_unlock(task); | |
1760 | return 0; | |
1761 | } |