4 * Copyright (C) 1991, 1992 Linus Torvalds
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()'
14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/unistd.h>
17 #include <linux/module.h>
18 #include <linux/vmalloc.h>
19 #include <linux/completion.h>
20 #include <linux/personality.h>
21 #include <linux/mempolicy.h>
22 #include <linux/sem.h>
23 #include <linux/file.h>
24 #include <linux/fdtable.h>
25 #include <linux/iocontext.h>
26 #include <linux/key.h>
27 #include <linux/binfmts.h>
28 #include <linux/mman.h>
29 #include <linux/mmu_notifier.h>
31 #include <linux/nsproxy.h>
32 #include <linux/capability.h>
33 #include <linux/cpu.h>
34 #include <linux/cgroup.h>
35 #include <linux/security.h>
36 #include <linux/hugetlb.h>
37 #include <linux/swap.h>
38 #include <linux/syscalls.h>
39 #include <linux/jiffies.h>
40 #include <linux/futex.h>
41 #include <linux/compat.h>
42 #include <linux/kthread.h>
43 #include <linux/task_io_accounting_ops.h>
44 #include <linux/rcupdate.h>
45 #include <linux/ptrace.h>
46 #include <linux/mount.h>
47 #include <linux/audit.h>
48 #include <linux/memcontrol.h>
49 #include <linux/ftrace.h>
50 #include <linux/proc_fs.h>
51 #include <linux/profile.h>
52 #include <linux/rmap.h>
53 #include <linux/ksm.h>
54 #include <linux/acct.h>
55 #include <linux/tsacct_kern.h>
56 #include <linux/cn_proc.h>
57 #include <linux/freezer.h>
58 #include <linux/kaiser.h>
59 #include <linux/delayacct.h>
60 #include <linux/taskstats_kern.h>
61 #include <linux/random.h>
62 #include <linux/tty.h>
63 #include <linux/blkdev.h>
64 #include <linux/fs_struct.h>
65 #include <linux/magic.h>
66 #include <linux/perf_event.h>
67 #include <linux/posix-timers.h>
68 #include <linux/user-return-notifier.h>
69 #include <linux/oom.h>
70 #include <linux/khugepaged.h>
71 #include <linux/signalfd.h>
73 #include <asm/pgtable.h>
74 #include <asm/pgalloc.h>
75 #include <asm/uaccess.h>
76 #include <asm/mmu_context.h>
77 #include <asm/cacheflush.h>
78 #include <asm/tlbflush.h>
80 #include <trace/events/sched.h>
83 * Protected counters by write_lock_irq(&tasklist_lock)
85 unsigned long total_forks; /* Handle normal Linux uptimes. */
86 int nr_threads; /* The idle threads do not count.. */
88 int max_threads; /* tunable limit on nr_threads */
90 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
92 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
94 #ifdef CONFIG_PROVE_RCU
95 int lockdep_tasklist_lock_is_held(void)
97 return lockdep_is_held(&tasklist_lock);
99 EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
100 #endif /* #ifdef CONFIG_PROVE_RCU */
102 int nr_processes(void)
107 for_each_possible_cpu(cpu)
108 total += per_cpu(process_counts, cpu);
113 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
114 # define alloc_task_struct_node(node) \
115 kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node)
116 # define free_task_struct(tsk) \
117 kmem_cache_free(task_struct_cachep, (tsk))
118 static struct kmem_cache *task_struct_cachep;
121 #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
122 static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
125 #ifdef CONFIG_DEBUG_STACK_USAGE
126 gfp_t mask = GFP_KERNEL | __GFP_ZERO;
128 gfp_t mask = GFP_KERNEL;
130 struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
132 return page ? page_address(page) : NULL;
135 static inline void free_thread_info(struct thread_info *ti)
137 kaiser_unmap_thread_stack(ti);
138 free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
142 /* SLAB cache for signal_struct structures (tsk->signal) */
143 static struct kmem_cache *signal_cachep;
145 /* SLAB cache for sighand_struct structures (tsk->sighand) */
146 struct kmem_cache *sighand_cachep;
148 /* SLAB cache for files_struct structures (tsk->files) */
149 struct kmem_cache *files_cachep;
151 /* SLAB cache for fs_struct structures (tsk->fs) */
152 struct kmem_cache *fs_cachep;
154 /* SLAB cache for vm_area_struct structures */
155 struct kmem_cache *vm_area_cachep;
157 /* SLAB cache for mm_struct structures (tsk->mm) */
158 static struct kmem_cache *mm_cachep;
160 static void account_kernel_stack(struct thread_info *ti, int account)
162 struct zone *zone = page_zone(virt_to_page(ti));
164 mod_zone_page_state(zone, NR_KERNEL_STACK, account);
167 void free_task(struct task_struct *tsk)
169 account_kernel_stack(tsk->stack, -1);
170 free_thread_info(tsk->stack);
171 rt_mutex_debug_task_free(tsk);
172 ftrace_graph_exit_task(tsk);
173 free_task_struct(tsk);
175 EXPORT_SYMBOL(free_task);
177 static inline void free_signal_struct(struct signal_struct *sig)
179 taskstats_tgid_free(sig);
180 sched_autogroup_exit(sig);
181 kmem_cache_free(signal_cachep, sig);
184 static inline void put_signal_struct(struct signal_struct *sig)
186 if (atomic_dec_and_test(&sig->sigcnt))
187 free_signal_struct(sig);
190 void __put_task_struct(struct task_struct *tsk)
192 WARN_ON(!tsk->exit_state);
193 WARN_ON(atomic_read(&tsk->usage));
194 WARN_ON(tsk == current);
197 delayacct_tsk_free(tsk);
198 put_signal_struct(tsk->signal);
200 if (!profile_handoff_task(tsk))
203 EXPORT_SYMBOL_GPL(__put_task_struct);
206 * macro override instead of weak attribute alias, to workaround
207 * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
209 #ifndef arch_task_cache_init
210 #define arch_task_cache_init()
213 void __init fork_init(unsigned long mempages)
215 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
216 #ifndef ARCH_MIN_TASKALIGN
217 #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
219 /* create a slab on which task_structs can be allocated */
221 kmem_cache_create("task_struct", sizeof(struct task_struct),
222 ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL);
225 /* do the arch specific task caches init */
226 arch_task_cache_init();
229 * The default maximum number of threads is set to a safe
230 * value: the thread structures can take up at most half
233 max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
236 * we need to allow at least 20 threads to boot a system
238 if (max_threads < 20)
241 init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
242 init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
243 init_task.signal->rlim[RLIMIT_SIGPENDING] =
244 init_task.signal->rlim[RLIMIT_NPROC];
247 int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst,
248 struct task_struct *src)
254 static struct task_struct *dup_task_struct(struct task_struct *orig)
256 struct task_struct *tsk;
257 struct thread_info *ti;
258 unsigned long *stackend;
259 int node = tsk_fork_get_node(orig);
262 prepare_to_copy(orig);
264 tsk = alloc_task_struct_node(node);
268 ti = alloc_thread_info_node(tsk, node);
270 free_task_struct(tsk);
274 err = arch_dup_task_struct(tsk, orig);
280 err = kaiser_map_thread_stack(tsk->stack);
284 setup_thread_stack(tsk, orig);
285 clear_user_return_notifier(tsk);
286 clear_tsk_need_resched(tsk);
287 stackend = end_of_stack(tsk);
288 *stackend = STACK_END_MAGIC; /* for overflow detection */
290 #ifdef CONFIG_CC_STACKPROTECTOR
291 tsk->stack_canary = get_random_int();
295 * One for us, one for whoever does the "release_task()" (usually
298 atomic_set(&tsk->usage, 2);
299 #ifdef CONFIG_BLK_DEV_IO_TRACE
302 tsk->splice_pipe = NULL;
304 account_kernel_stack(ti, 1);
309 free_thread_info(ti);
310 free_task_struct(tsk);
315 static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
317 struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
318 struct rb_node **rb_link, *rb_parent;
320 unsigned long charge;
321 struct mempolicy *pol;
323 down_write(&oldmm->mmap_sem);
324 flush_cache_dup_mm(oldmm);
326 * Not linked in yet - no deadlock potential:
328 down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
332 mm->mmap_cache = NULL;
333 mm->free_area_cache = oldmm->mmap_base;
334 mm->cached_hole_size = ~0UL;
336 cpumask_clear(mm_cpumask(mm));
338 rb_link = &mm->mm_rb.rb_node;
341 retval = ksm_fork(mm, oldmm);
344 retval = khugepaged_fork(mm, oldmm);
349 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
352 if (mpnt->vm_flags & VM_DONTCOPY) {
353 long pages = vma_pages(mpnt);
354 mm->total_vm -= pages;
355 vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
360 if (mpnt->vm_flags & VM_ACCOUNT) {
362 len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
363 if (security_vm_enough_memory(len))
367 tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
371 INIT_LIST_HEAD(&tmp->anon_vma_chain);
372 pol = mpol_dup(vma_policy(mpnt));
373 retval = PTR_ERR(pol);
375 goto fail_nomem_policy;
376 vma_set_policy(tmp, pol);
378 if (anon_vma_fork(tmp, mpnt))
379 goto fail_nomem_anon_vma_fork;
380 tmp->vm_flags &= ~VM_LOCKED;
381 tmp->vm_next = tmp->vm_prev = NULL;
384 struct inode *inode = file->f_path.dentry->d_inode;
385 struct address_space *mapping = file->f_mapping;
388 if (tmp->vm_flags & VM_DENYWRITE)
389 atomic_dec(&inode->i_writecount);
390 mutex_lock(&mapping->i_mmap_mutex);
391 if (tmp->vm_flags & VM_SHARED)
392 mapping->i_mmap_writable++;
393 flush_dcache_mmap_lock(mapping);
394 /* insert tmp into the share list, just after mpnt */
395 vma_prio_tree_add(tmp, mpnt);
396 flush_dcache_mmap_unlock(mapping);
397 mutex_unlock(&mapping->i_mmap_mutex);
401 * Clear hugetlb-related page reserves for children. This only
402 * affects MAP_PRIVATE mappings. Faults generated by the child
403 * are not guaranteed to succeed, even if read-only
405 if (is_vm_hugetlb_page(tmp))
406 reset_vma_resv_huge_pages(tmp);
409 * Link in the new vma and copy the page table entries.
412 pprev = &tmp->vm_next;
416 __vma_link_rb(mm, tmp, rb_link, rb_parent);
417 rb_link = &tmp->vm_rb.rb_right;
418 rb_parent = &tmp->vm_rb;
421 retval = copy_page_range(mm, oldmm, mpnt);
423 if (tmp->vm_ops && tmp->vm_ops->open)
424 tmp->vm_ops->open(tmp);
429 /* a new mm has just been created */
430 arch_dup_mmap(oldmm, mm);
433 up_write(&mm->mmap_sem);
435 up_write(&oldmm->mmap_sem);
437 fail_nomem_anon_vma_fork:
440 kmem_cache_free(vm_area_cachep, tmp);
443 vm_unacct_memory(charge);
447 static inline int mm_alloc_pgd(struct mm_struct *mm)
449 mm->pgd = pgd_alloc(mm);
450 if (unlikely(!mm->pgd))
455 static inline void mm_free_pgd(struct mm_struct *mm)
457 pgd_free(mm, mm->pgd);
460 #define dup_mmap(mm, oldmm) (0)
461 #define mm_alloc_pgd(mm) (0)
462 #define mm_free_pgd(mm)
463 #endif /* CONFIG_MMU */
465 __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
467 #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
468 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
470 static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
472 static int __init coredump_filter_setup(char *s)
474 default_dump_filter =
475 (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
476 MMF_DUMP_FILTER_MASK;
480 __setup("coredump_filter=", coredump_filter_setup);
482 #include <linux/init_task.h>
484 static void mm_init_aio(struct mm_struct *mm)
487 spin_lock_init(&mm->ioctx_lock);
488 INIT_HLIST_HEAD(&mm->ioctx_list);
492 static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
494 atomic_set(&mm->mm_users, 1);
495 atomic_set(&mm->mm_count, 1);
496 init_rwsem(&mm->mmap_sem);
497 INIT_LIST_HEAD(&mm->mmlist);
498 mm->flags = (current->mm) ?
499 (current->mm->flags & MMF_INIT_MASK) : default_dump_filter;
500 mm->core_state = NULL;
502 memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
503 spin_lock_init(&mm->page_table_lock);
504 mm->free_area_cache = TASK_UNMAPPED_BASE;
505 mm->cached_hole_size = ~0UL;
507 mm_init_owner(mm, p);
509 if (likely(!mm_alloc_pgd(mm))) {
511 mmu_notifier_mm_init(mm);
520 * Allocate and initialize an mm_struct.
522 struct mm_struct *mm_alloc(void)
524 struct mm_struct *mm;
530 memset(mm, 0, sizeof(*mm));
532 return mm_init(mm, current);
536 * Called when the last reference to the mm
537 * is dropped: either by a lazy thread or by
538 * mmput. Free the page directory and the mm.
540 void __mmdrop(struct mm_struct *mm)
542 BUG_ON(mm == &init_mm);
545 mmu_notifier_mm_destroy(mm);
546 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
547 VM_BUG_ON(mm->pmd_huge_pte);
551 EXPORT_SYMBOL_GPL(__mmdrop);
554 * Decrement the use count and release all resources for an mm.
556 void mmput(struct mm_struct *mm)
560 if (atomic_dec_and_test(&mm->mm_users)) {
563 khugepaged_exit(mm); /* must run before exit_mmap */
565 set_mm_exe_file(mm, NULL);
566 if (!list_empty(&mm->mmlist)) {
567 spin_lock(&mmlist_lock);
568 list_del(&mm->mmlist);
569 spin_unlock(&mmlist_lock);
573 module_put(mm->binfmt->module);
577 EXPORT_SYMBOL_GPL(mmput);
580 * We added or removed a vma mapping the executable. The vmas are only mapped
581 * during exec and are not mapped with the mmap system call.
582 * Callers must hold down_write() on the mm's mmap_sem for these
584 void added_exe_file_vma(struct mm_struct *mm)
586 mm->num_exe_file_vmas++;
589 void removed_exe_file_vma(struct mm_struct *mm)
591 mm->num_exe_file_vmas--;
592 if ((mm->num_exe_file_vmas == 0) && mm->exe_file) {
599 void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
602 get_file(new_exe_file);
605 mm->exe_file = new_exe_file;
606 mm->num_exe_file_vmas = 0;
609 struct file *get_mm_exe_file(struct mm_struct *mm)
611 struct file *exe_file;
613 /* We need mmap_sem to protect against races with removal of
614 * VM_EXECUTABLE vmas */
615 down_read(&mm->mmap_sem);
616 exe_file = mm->exe_file;
619 up_read(&mm->mmap_sem);
623 static void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
625 /* It's safe to write the exe_file pointer without exe_file_lock because
626 * this is called during fork when the task is not yet in /proc */
627 newmm->exe_file = get_mm_exe_file(oldmm);
631 * get_task_mm - acquire a reference to the task's mm
633 * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
634 * this kernel workthread has transiently adopted a user mm with use_mm,
635 * to do its AIO) is not set and if so returns a reference to it, after
636 * bumping up the use count. User must release the mm via mmput()
637 * after use. Typically used by /proc and ptrace.
639 struct mm_struct *get_task_mm(struct task_struct *task)
641 struct mm_struct *mm;
646 if (task->flags & PF_KTHREAD)
649 atomic_inc(&mm->mm_users);
654 EXPORT_SYMBOL_GPL(get_task_mm);
656 /* Please note the differences between mmput and mm_release.
657 * mmput is called whenever we stop holding onto a mm_struct,
658 * error success whatever.
660 * mm_release is called after a mm_struct has been removed
661 * from the current process.
663 * This difference is important for error handling, when we
664 * only half set up a mm_struct for a new process and need to restore
665 * the old one. Because we mmput the new mm_struct before
666 * restoring the old one. . .
667 * Eric Biederman 10 January 1998
669 void mm_release(struct task_struct *tsk, struct mm_struct *mm)
671 struct completion *vfork_done = tsk->vfork_done;
673 /* Get rid of any futexes when releasing the mm */
675 if (unlikely(tsk->robust_list)) {
676 exit_robust_list(tsk);
677 tsk->robust_list = NULL;
680 if (unlikely(tsk->compat_robust_list)) {
681 compat_exit_robust_list(tsk);
682 tsk->compat_robust_list = NULL;
685 if (unlikely(!list_empty(&tsk->pi_state_list)))
686 exit_pi_state_list(tsk);
689 /* Get rid of any cached register state */
690 deactivate_mm(tsk, mm);
692 /* notify parent sleeping on vfork() */
694 tsk->vfork_done = NULL;
695 complete(vfork_done);
699 * If we're exiting normally, clear a user-space tid field if
700 * requested. We leave this alone when dying by signal, to leave
701 * the value intact in a core dump, and to save the unnecessary
702 * trouble otherwise. Userland only wants this done for a sys_exit.
704 if (tsk->clear_child_tid) {
705 if (!(tsk->flags & PF_SIGNALED) &&
706 atomic_read(&mm->mm_users) > 1) {
708 * We don't check the error code - if userspace has
709 * not set up a proper pointer then tough luck.
711 put_user(0, tsk->clear_child_tid);
712 sys_futex(tsk->clear_child_tid, FUTEX_WAKE,
715 tsk->clear_child_tid = NULL;
720 * Allocate a new mm structure and copy contents from the
721 * mm structure of the passed in task structure.
723 struct mm_struct *dup_mm(struct task_struct *tsk)
725 struct mm_struct *mm, *oldmm = current->mm;
735 memcpy(mm, oldmm, sizeof(*mm));
738 /* Initializing for Swap token stuff */
739 mm->token_priority = 0;
740 mm->last_interval = 0;
742 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
743 mm->pmd_huge_pte = NULL;
746 if (!mm_init(mm, tsk))
749 if (init_new_context(tsk, mm))
752 dup_mm_exe_file(oldmm, mm);
754 err = dup_mmap(mm, oldmm);
758 mm->hiwater_rss = get_mm_rss(mm);
759 mm->hiwater_vm = mm->total_vm;
761 if (mm->binfmt && !try_module_get(mm->binfmt->module))
767 /* don't put binfmt in mmput, we haven't got module yet */
776 * If init_new_context() failed, we cannot use mmput() to free the mm
777 * because it calls destroy_context()
784 static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
786 struct mm_struct *mm, *oldmm;
789 tsk->min_flt = tsk->maj_flt = 0;
790 tsk->nvcsw = tsk->nivcsw = 0;
791 #ifdef CONFIG_DETECT_HUNG_TASK
792 tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
796 tsk->active_mm = NULL;
799 * Are we cloning a kernel thread?
801 * We need to steal a active VM for that..
807 if (clone_flags & CLONE_VM) {
808 atomic_inc(&oldmm->mm_users);
819 /* Initializing for Swap token stuff */
820 mm->token_priority = 0;
821 mm->last_interval = 0;
831 static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
833 struct fs_struct *fs = current->fs;
834 if (clone_flags & CLONE_FS) {
835 /* tsk->fs is already what we want */
836 spin_lock(&fs->lock);
838 spin_unlock(&fs->lock);
842 spin_unlock(&fs->lock);
845 tsk->fs = copy_fs_struct(fs);
851 static int copy_files(unsigned long clone_flags, struct task_struct *tsk)
853 struct files_struct *oldf, *newf;
857 * A background process may not have any files ...
859 oldf = current->files;
863 if (clone_flags & CLONE_FILES) {
864 atomic_inc(&oldf->count);
868 newf = dup_fd(oldf, &error);
878 static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
881 struct io_context *ioc = current->io_context;
886 * Share io context with parent, if CLONE_IO is set
888 if (clone_flags & CLONE_IO) {
889 tsk->io_context = ioc_task_link(ioc);
890 if (unlikely(!tsk->io_context))
892 } else if (ioprio_valid(ioc->ioprio)) {
893 tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
894 if (unlikely(!tsk->io_context))
897 tsk->io_context->ioprio = ioc->ioprio;
903 static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
905 struct sighand_struct *sig;
907 if (clone_flags & CLONE_SIGHAND) {
908 atomic_inc(¤t->sighand->count);
911 sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
912 rcu_assign_pointer(tsk->sighand, sig);
915 atomic_set(&sig->count, 1);
916 memcpy(sig->action, current->sighand->action, sizeof(sig->action));
920 void __cleanup_sighand(struct sighand_struct *sighand)
922 if (atomic_dec_and_test(&sighand->count)) {
923 signalfd_cleanup(sighand);
924 kmem_cache_free(sighand_cachep, sighand);
930 * Initialize POSIX timer handling for a thread group.
932 static void posix_cpu_timers_init_group(struct signal_struct *sig)
934 unsigned long cpu_limit;
936 /* Thread group counters. */
937 thread_group_cputime_init(sig);
939 cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
940 if (cpu_limit != RLIM_INFINITY) {
941 sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
942 sig->cputimer.running = 1;
945 /* The timer lists. */
946 INIT_LIST_HEAD(&sig->cpu_timers[0]);
947 INIT_LIST_HEAD(&sig->cpu_timers[1]);
948 INIT_LIST_HEAD(&sig->cpu_timers[2]);
951 static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
953 struct signal_struct *sig;
955 if (clone_flags & CLONE_THREAD)
958 sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
964 atomic_set(&sig->live, 1);
965 atomic_set(&sig->sigcnt, 1);
966 init_waitqueue_head(&sig->wait_chldexit);
967 if (clone_flags & CLONE_NEWPID)
968 sig->flags |= SIGNAL_UNKILLABLE;
969 sig->curr_target = tsk;
970 init_sigpending(&sig->shared_pending);
971 INIT_LIST_HEAD(&sig->posix_timers);
973 hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
974 sig->real_timer.function = it_real_fn;
976 task_lock(current->group_leader);
977 memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
978 task_unlock(current->group_leader);
980 posix_cpu_timers_init_group(sig);
983 sched_autogroup_fork(sig);
985 #ifdef CONFIG_CGROUPS
986 init_rwsem(&sig->threadgroup_fork_lock);
988 #ifdef CONFIG_CPUSETS
989 seqcount_init(&tsk->mems_allowed_seq);
992 sig->oom_adj = current->signal->oom_adj;
993 sig->oom_score_adj = current->signal->oom_score_adj;
994 sig->oom_score_adj_min = current->signal->oom_score_adj_min;
996 mutex_init(&sig->cred_guard_mutex);
1001 static void copy_flags(unsigned long clone_flags, struct task_struct *p)
1003 unsigned long new_flags = p->flags;
1005 new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
1006 new_flags |= PF_FORKNOEXEC;
1007 new_flags |= PF_STARTING;
1008 p->flags = new_flags;
1009 clear_freeze_flag(p);
1012 SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
1014 current->clear_child_tid = tidptr;
1016 return task_pid_vnr(current);
1019 static void rt_mutex_init_task(struct task_struct *p)
1021 raw_spin_lock_init(&p->pi_lock);
1022 #ifdef CONFIG_RT_MUTEXES
1023 plist_head_init(&p->pi_waiters);
1024 p->pi_blocked_on = NULL;
1028 #ifdef CONFIG_MM_OWNER
1029 void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
1033 #endif /* CONFIG_MM_OWNER */
1036 * Initialize POSIX timer handling for a single task.
1038 static void posix_cpu_timers_init(struct task_struct *tsk)
1040 tsk->cputime_expires.prof_exp = cputime_zero;
1041 tsk->cputime_expires.virt_exp = cputime_zero;
1042 tsk->cputime_expires.sched_exp = 0;
1043 INIT_LIST_HEAD(&tsk->cpu_timers[0]);
1044 INIT_LIST_HEAD(&tsk->cpu_timers[1]);
1045 INIT_LIST_HEAD(&tsk->cpu_timers[2]);
1049 * This creates a new process as a copy of the old one,
1050 * but does not actually start it yet.
1052 * It copies the registers, and all the appropriate
1053 * parts of the process environment (as per the clone
1054 * flags). The actual kick-off is left to the caller.
1056 static struct task_struct *copy_process(unsigned long clone_flags,
1057 unsigned long stack_start,
1058 struct pt_regs *regs,
1059 unsigned long stack_size,
1060 int __user *child_tidptr,
1065 struct task_struct *p;
1067 if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
1068 return ERR_PTR(-EINVAL);
1071 * Thread groups must share signals as well, and detached threads
1072 * can only be started up within the thread group.
1074 if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
1075 return ERR_PTR(-EINVAL);
1078 * Shared signal handlers imply shared VM. By way of the above,
1079 * thread groups also imply shared VM. Blocking this case allows
1080 * for various simplifications in other code.
1082 if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
1083 return ERR_PTR(-EINVAL);
1086 * Siblings of global init remain as zombies on exit since they are
1087 * not reaped by their parent (swapper). To solve this and to avoid
1088 * multi-rooted process trees, prevent global and container-inits
1089 * from creating siblings.
1091 if ((clone_flags & CLONE_PARENT) &&
1092 current->signal->flags & SIGNAL_UNKILLABLE)
1093 return ERR_PTR(-EINVAL);
1095 retval = security_task_create(clone_flags);
1100 p = dup_task_struct(current);
1104 ftrace_graph_init_task(p);
1106 rt_mutex_init_task(p);
1108 #ifdef CONFIG_PROVE_LOCKING
1109 DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
1110 DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
1113 if (atomic_read(&p->real_cred->user->processes) >=
1114 task_rlimit(p, RLIMIT_NPROC)) {
1115 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
1116 p->real_cred->user != INIT_USER)
1119 current->flags &= ~PF_NPROC_EXCEEDED;
1121 retval = copy_creds(p, clone_flags);
1126 * If multiple threads are within copy_process(), then this check
1127 * triggers too late. This doesn't hurt, the check is only there
1128 * to stop root fork bombs.
1131 if (nr_threads >= max_threads)
1132 goto bad_fork_cleanup_count;
1134 if (!try_module_get(task_thread_info(p)->exec_domain->module))
1135 goto bad_fork_cleanup_count;
1138 delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
1139 copy_flags(clone_flags, p);
1140 INIT_LIST_HEAD(&p->children);
1141 INIT_LIST_HEAD(&p->sibling);
1142 rcu_copy_process(p);
1143 p->vfork_done = NULL;
1144 spin_lock_init(&p->alloc_lock);
1146 init_sigpending(&p->pending);
1148 p->utime = cputime_zero;
1149 p->stime = cputime_zero;
1150 p->gtime = cputime_zero;
1151 p->utimescaled = cputime_zero;
1152 p->stimescaled = cputime_zero;
1153 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
1154 p->prev_utime = cputime_zero;
1155 p->prev_stime = cputime_zero;
1157 #if defined(SPLIT_RSS_COUNTING)
1158 memset(&p->rss_stat, 0, sizeof(p->rss_stat));
1161 p->default_timer_slack_ns = current->timer_slack_ns;
1163 task_io_accounting_init(&p->ioac);
1164 acct_clear_integrals(p);
1166 posix_cpu_timers_init(p);
1168 do_posix_clock_monotonic_gettime(&p->start_time);
1169 p->real_start_time = p->start_time;
1170 monotonic_to_bootbased(&p->real_start_time);
1171 p->io_context = NULL;
1172 p->audit_context = NULL;
1173 if (clone_flags & CLONE_THREAD)
1174 threadgroup_fork_read_lock(current);
1177 p->mempolicy = mpol_dup(p->mempolicy);
1178 if (IS_ERR(p->mempolicy)) {
1179 retval = PTR_ERR(p->mempolicy);
1180 p->mempolicy = NULL;
1181 goto bad_fork_cleanup_cgroup;
1183 mpol_fix_fork_child_flag(p);
1185 #ifdef CONFIG_CPUSETS
1186 p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
1187 p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
1189 #ifdef CONFIG_TRACE_IRQFLAGS
1191 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1192 p->hardirqs_enabled = 1;
1194 p->hardirqs_enabled = 0;
1196 p->hardirq_enable_ip = 0;
1197 p->hardirq_enable_event = 0;
1198 p->hardirq_disable_ip = _THIS_IP_;
1199 p->hardirq_disable_event = 0;
1200 p->softirqs_enabled = 1;
1201 p->softirq_enable_ip = _THIS_IP_;
1202 p->softirq_enable_event = 0;
1203 p->softirq_disable_ip = 0;
1204 p->softirq_disable_event = 0;
1205 p->hardirq_context = 0;
1206 p->softirq_context = 0;
1208 #ifdef CONFIG_LOCKDEP
1209 p->lockdep_depth = 0; /* no locks held yet */
1210 p->curr_chain_key = 0;
1211 p->lockdep_recursion = 0;
1214 #ifdef CONFIG_DEBUG_MUTEXES
1215 p->blocked_on = NULL; /* not blocked yet */
1217 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
1218 p->memcg_batch.do_batch = 0;
1219 p->memcg_batch.memcg = NULL;
1222 /* Perform scheduler related setup. Assign this task to a CPU. */
1225 retval = perf_event_init_task(p);
1227 goto bad_fork_cleanup_policy;
1228 retval = audit_alloc(p);
1230 goto bad_fork_cleanup_perf;
1231 /* copy all the process information */
1232 retval = copy_semundo(clone_flags, p);
1234 goto bad_fork_cleanup_audit;
1235 retval = copy_files(clone_flags, p);
1237 goto bad_fork_cleanup_semundo;
1238 retval = copy_fs(clone_flags, p);
1240 goto bad_fork_cleanup_files;
1241 retval = copy_sighand(clone_flags, p);
1243 goto bad_fork_cleanup_fs;
1244 retval = copy_signal(clone_flags, p);
1246 goto bad_fork_cleanup_sighand;
1247 retval = copy_mm(clone_flags, p);
1249 goto bad_fork_cleanup_signal;
1250 retval = copy_namespaces(clone_flags, p);
1252 goto bad_fork_cleanup_mm;
1253 retval = copy_io(clone_flags, p);
1255 goto bad_fork_cleanup_namespaces;
1256 retval = copy_thread(clone_flags, stack_start, stack_size, p, regs);
1258 goto bad_fork_cleanup_io;
1260 if (pid != &init_struct_pid) {
1262 pid = alloc_pid(p->nsproxy->pid_ns);
1264 goto bad_fork_cleanup_io;
1267 p->pid = pid_nr(pid);
1269 if (clone_flags & CLONE_THREAD)
1270 p->tgid = current->tgid;
1272 p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1274 * Clear TID on mm_release()?
1276 p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL;
1281 p->robust_list = NULL;
1282 #ifdef CONFIG_COMPAT
1283 p->compat_robust_list = NULL;
1285 INIT_LIST_HEAD(&p->pi_state_list);
1286 p->pi_state_cache = NULL;
1289 * sigaltstack should be cleared when sharing the same VM
1291 if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
1292 p->sas_ss_sp = p->sas_ss_size = 0;
1295 * Syscall tracing and stepping should be turned off in the
1296 * child regardless of CLONE_PTRACE.
1298 user_disable_single_step(p);
1299 clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
1300 #ifdef TIF_SYSCALL_EMU
1301 clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
1303 clear_all_latency_tracing(p);
1305 /* ok, now we should be set up.. */
1306 p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
1307 p->pdeath_signal = 0;
1311 p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
1314 * Ok, make it visible to the rest of the system.
1315 * We dont wake it up yet.
1317 p->group_leader = p;
1318 INIT_LIST_HEAD(&p->thread_group);
1320 /* Need tasklist lock for parent etc handling! */
1321 write_lock_irq(&tasklist_lock);
1323 /* CLONE_PARENT re-uses the old parent */
1324 if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
1325 p->real_parent = current->real_parent;
1326 p->parent_exec_id = current->parent_exec_id;
1328 p->real_parent = current;
1329 p->parent_exec_id = current->self_exec_id;
1332 spin_lock(¤t->sighand->siglock);
1335 * Process group and session signals need to be delivered to just the
1336 * parent before the fork or both the parent and the child after the
1337 * fork. Restart if a signal comes in before we add the new process to
1338 * it's process group.
1339 * A fatal signal pending means that current will exit, so the new
1340 * thread can't slip out of an OOM kill (or normal SIGKILL).
1342 recalc_sigpending();
1343 if (signal_pending(current)) {
1344 spin_unlock(¤t->sighand->siglock);
1345 write_unlock_irq(&tasklist_lock);
1346 retval = -ERESTARTNOINTR;
1347 goto bad_fork_free_pid;
1350 if (clone_flags & CLONE_THREAD) {
1351 current->signal->nr_threads++;
1352 atomic_inc(¤t->signal->live);
1353 atomic_inc(¤t->signal->sigcnt);
1354 p->group_leader = current->group_leader;
1355 list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
1358 if (likely(p->pid)) {
1359 ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
1361 if (thread_group_leader(p)) {
1362 if (is_child_reaper(pid))
1363 p->nsproxy->pid_ns->child_reaper = p;
1365 p->signal->leader_pid = pid;
1366 p->signal->tty = tty_kref_get(current->signal->tty);
1367 attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
1368 attach_pid(p, PIDTYPE_SID, task_session(current));
1369 list_add_tail(&p->sibling, &p->real_parent->children);
1370 list_add_tail_rcu(&p->tasks, &init_task.tasks);
1371 __this_cpu_inc(process_counts);
1373 attach_pid(p, PIDTYPE_PID, pid);
1378 spin_unlock(¤t->sighand->siglock);
1379 syscall_tracepoint_update(p);
1380 write_unlock_irq(&tasklist_lock);
1382 proc_fork_connector(p);
1383 cgroup_post_fork(p);
1384 if (clone_flags & CLONE_THREAD)
1385 threadgroup_fork_read_unlock(current);
1390 if (pid != &init_struct_pid)
1392 bad_fork_cleanup_io:
1395 bad_fork_cleanup_namespaces:
1396 if (unlikely(clone_flags & CLONE_NEWPID))
1397 pid_ns_release_proc(p->nsproxy->pid_ns);
1398 exit_task_namespaces(p);
1399 bad_fork_cleanup_mm:
1402 bad_fork_cleanup_signal:
1403 if (!(clone_flags & CLONE_THREAD))
1404 free_signal_struct(p->signal);
1405 bad_fork_cleanup_sighand:
1406 __cleanup_sighand(p->sighand);
1407 bad_fork_cleanup_fs:
1408 exit_fs(p); /* blocking */
1409 bad_fork_cleanup_files:
1410 exit_files(p); /* blocking */
1411 bad_fork_cleanup_semundo:
1413 bad_fork_cleanup_audit:
1415 bad_fork_cleanup_perf:
1416 perf_event_free_task(p);
1417 bad_fork_cleanup_policy:
1419 mpol_put(p->mempolicy);
1420 bad_fork_cleanup_cgroup:
1422 if (clone_flags & CLONE_THREAD)
1423 threadgroup_fork_read_unlock(current);
1425 delayacct_tsk_free(p);
1426 module_put(task_thread_info(p)->exec_domain->module);
1427 bad_fork_cleanup_count:
1428 atomic_dec(&p->cred->user->processes);
1433 return ERR_PTR(retval);
1436 noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
1438 memset(regs, 0, sizeof(struct pt_regs));
1442 static inline void init_idle_pids(struct pid_link *links)
1446 for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
1447 INIT_HLIST_NODE(&links[type].node); /* not really needed */
1448 links[type].pid = &init_struct_pid;
1452 struct task_struct * __cpuinit fork_idle(int cpu)
1454 struct task_struct *task;
1455 struct pt_regs regs;
1457 task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL,
1458 &init_struct_pid, 0);
1459 if (!IS_ERR(task)) {
1460 init_idle_pids(task->pids);
1461 init_idle(task, cpu);
1468 * Ok, this is the main fork-routine.
1470 * It copies the process, and if successful kick-starts
1471 * it and waits for it to finish using the VM if required.
1473 long do_fork(unsigned long clone_flags,
1474 unsigned long stack_start,
1475 struct pt_regs *regs,
1476 unsigned long stack_size,
1477 int __user *parent_tidptr,
1478 int __user *child_tidptr)
1480 struct task_struct *p;
1485 * Do some preliminary argument and permissions checking before we
1486 * actually start allocating stuff
1488 if (clone_flags & CLONE_NEWUSER) {
1489 if (clone_flags & CLONE_THREAD)
1491 /* hopefully this check will go away when userns support is
1494 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) ||
1495 !capable(CAP_SETGID))
1500 * Determine whether and which event to report to ptracer. When
1501 * called from kernel_thread or CLONE_UNTRACED is explicitly
1502 * requested, no event is reported; otherwise, report if the event
1503 * for the type of forking is enabled.
1505 if (likely(user_mode(regs)) && !(clone_flags & CLONE_UNTRACED)) {
1506 if (clone_flags & CLONE_VFORK)
1507 trace = PTRACE_EVENT_VFORK;
1508 else if ((clone_flags & CSIGNAL) != SIGCHLD)
1509 trace = PTRACE_EVENT_CLONE;
1511 trace = PTRACE_EVENT_FORK;
1513 if (likely(!ptrace_event_enabled(current, trace)))
1517 p = copy_process(clone_flags, stack_start, regs, stack_size,
1518 child_tidptr, NULL, trace);
1520 * Do this prior waking up the new thread - the thread pointer
1521 * might get invalid after that point, if the thread exits quickly.
1524 struct completion vfork;
1527 trace_sched_process_fork(current, p);
1529 pid = get_task_pid(p, PIDTYPE_PID);
1532 if (clone_flags & CLONE_PARENT_SETTID)
1533 put_user(nr, parent_tidptr);
1535 if (clone_flags & CLONE_VFORK) {
1536 p->vfork_done = &vfork;
1537 init_completion(&vfork);
1540 audit_finish_fork(p);
1543 * We set PF_STARTING at creation in case tracing wants to
1544 * use this to distinguish a fully live task from one that
1545 * hasn't finished SIGSTOP raising yet. Now we clear it
1546 * and set the child going.
1548 p->flags &= ~PF_STARTING;
1550 wake_up_new_task(p);
1552 /* forking complete and child started to run, tell ptracer */
1553 if (unlikely(trace))
1554 ptrace_event_pid(trace, pid);
1556 if (clone_flags & CLONE_VFORK) {
1557 freezer_do_not_count();
1558 wait_for_completion(&vfork);
1560 ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
1570 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
1571 #define ARCH_MIN_MMSTRUCT_ALIGN 0
1574 static void sighand_ctor(void *data)
1576 struct sighand_struct *sighand = data;
1578 spin_lock_init(&sighand->siglock);
1579 init_waitqueue_head(&sighand->signalfd_wqh);
1582 void __init proc_caches_init(void)
1584 sighand_cachep = kmem_cache_create("sighand_cache",
1585 sizeof(struct sighand_struct), 0,
1586 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU|
1587 SLAB_NOTRACK, sighand_ctor);
1588 signal_cachep = kmem_cache_create("signal_cache",
1589 sizeof(struct signal_struct), 0,
1590 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
1591 files_cachep = kmem_cache_create("files_cache",
1592 sizeof(struct files_struct), 0,
1593 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
1594 fs_cachep = kmem_cache_create("fs_cache",
1595 sizeof(struct fs_struct), 0,
1596 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
1598 * FIXME! The "sizeof(struct mm_struct)" currently includes the
1599 * whole struct cpumask for the OFFSTACK case. We could change
1600 * this to *only* allocate as much of it as required by the
1601 * maximum number of CPU's we can ever have. The cpumask_allocation
1602 * is at the end of the structure, exactly for that reason.
1604 mm_cachep = kmem_cache_create("mm_struct",
1605 sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
1606 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
1607 vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC);
1609 nsproxy_cache_init();
1613 * Check constraints on flags passed to the unshare system call.
1615 static int check_unshare_flags(unsigned long unshare_flags)
1617 if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
1618 CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
1619 CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET))
1622 * Not implemented, but pretend it works if there is nothing to
1623 * unshare. Note that unsharing CLONE_THREAD or CLONE_SIGHAND
1624 * needs to unshare vm.
1626 if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
1627 /* FIXME: get_task_mm() increments ->mm_users */
1628 if (atomic_read(¤t->mm->mm_users) > 1)
1636 * Unshare the filesystem structure if it is being shared
1638 static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
1640 struct fs_struct *fs = current->fs;
1642 if (!(unshare_flags & CLONE_FS) || !fs)
1645 /* don't need lock here; in the worst case we'll do useless copy */
1649 *new_fsp = copy_fs_struct(fs);
1657 * Unshare file descriptor table if it is being shared
1659 static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
1661 struct files_struct *fd = current->files;
1664 if ((unshare_flags & CLONE_FILES) &&
1665 (fd && atomic_read(&fd->count) > 1)) {
1666 *new_fdp = dup_fd(fd, &error);
1675 * unshare allows a process to 'unshare' part of the process
1676 * context which was originally shared using clone. copy_*
1677 * functions used by do_fork() cannot be used here directly
1678 * because they modify an inactive task_struct that is being
1679 * constructed. Here we are modifying the current, active,
1682 SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
1684 struct fs_struct *fs, *new_fs = NULL;
1685 struct files_struct *fd, *new_fd = NULL;
1686 struct nsproxy *new_nsproxy = NULL;
1690 err = check_unshare_flags(unshare_flags);
1692 goto bad_unshare_out;
1695 * If unsharing namespace, must also unshare filesystem information.
1697 if (unshare_flags & CLONE_NEWNS)
1698 unshare_flags |= CLONE_FS;
1700 * CLONE_NEWIPC must also detach from the undolist: after switching
1701 * to a new ipc namespace, the semaphore arrays from the old
1702 * namespace are unreachable.
1704 if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
1706 err = unshare_fs(unshare_flags, &new_fs);
1708 goto bad_unshare_out;
1709 err = unshare_fd(unshare_flags, &new_fd);
1711 goto bad_unshare_cleanup_fs;
1712 err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, new_fs);
1714 goto bad_unshare_cleanup_fd;
1716 if (new_fs || new_fd || do_sysvsem || new_nsproxy) {
1719 * CLONE_SYSVSEM is equivalent to sys_exit().
1725 switch_task_namespaces(current, new_nsproxy);
1733 spin_lock(&fs->lock);
1734 current->fs = new_fs;
1739 spin_unlock(&fs->lock);
1743 fd = current->files;
1744 current->files = new_fd;
1748 task_unlock(current);
1752 put_nsproxy(new_nsproxy);
1754 bad_unshare_cleanup_fd:
1756 put_files_struct(new_fd);
1758 bad_unshare_cleanup_fs:
1760 free_fs_struct(new_fs);
1767 * Helper to unshare the files of the current task.
1768 * We don't want to expose copy_files internals to
1769 * the exec layer of the kernel.
1772 int unshare_files(struct files_struct **displaced)
1774 struct task_struct *task = current;
1775 struct files_struct *copy = NULL;
1778 error = unshare_fd(CLONE_FILES, ©);
1779 if (error || !copy) {
1783 *displaced = task->files;