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/mnt_namespace.h>
21 #include <linux/personality.h>
22 #include <linux/mempolicy.h>
23 #include <linux/sem.h>
24 #include <linux/file.h>
25 #include <linux/fdtable.h>
26 #include <linux/iocontext.h>
27 #include <linux/key.h>
28 #include <linux/binfmts.h>
29 #include <linux/mman.h>
30 #include <linux/mmu_notifier.h>
32 #include <linux/nsproxy.h>
33 #include <linux/capability.h>
34 #include <linux/cpu.h>
35 #include <linux/cgroup.h>
36 #include <linux/security.h>
37 #include <linux/hugetlb.h>
38 #include <linux/swap.h>
39 #include <linux/syscalls.h>
40 #include <linux/jiffies.h>
41 #include <linux/tracehook.h>
42 #include <linux/futex.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/profile.h>
50 #include <linux/rmap.h>
51 #include <linux/acct.h>
52 #include <linux/tsacct_kern.h>
53 #include <linux/cn_proc.h>
54 #include <linux/freezer.h>
55 #include <linux/delayacct.h>
56 #include <linux/taskstats_kern.h>
57 #include <linux/random.h>
58 #include <linux/tty.h>
59 #include <linux/proc_fs.h>
60 #include <linux/blkdev.h>
61 #include <trace/sched.h>
63 #include <asm/pgtable.h>
64 #include <asm/pgalloc.h>
65 #include <asm/uaccess.h>
66 #include <asm/mmu_context.h>
67 #include <asm/cacheflush.h>
68 #include <asm/tlbflush.h>
71 * Protected counters by write_lock_irq(&tasklist_lock)
73 unsigned long total_forks
; /* Handle normal Linux uptimes. */
74 int nr_threads
; /* The idle threads do not count.. */
76 int max_threads
; /* tunable limit on nr_threads */
78 DEFINE_PER_CPU(unsigned long, process_counts
) = 0;
80 __cacheline_aligned
DEFINE_RWLOCK(tasklist_lock
); /* outer */
82 int nr_processes(void)
87 for_each_online_cpu(cpu
)
88 total
+= per_cpu(process_counts
, cpu
);
93 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
94 # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
95 # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk))
96 static struct kmem_cache
*task_struct_cachep
;
99 #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
100 static inline struct thread_info
*alloc_thread_info(struct task_struct
*tsk
)
102 #ifdef CONFIG_DEBUG_STACK_USAGE
103 gfp_t mask
= GFP_KERNEL
| __GFP_ZERO
;
105 gfp_t mask
= GFP_KERNEL
;
107 return (struct thread_info
*)__get_free_pages(mask
, THREAD_SIZE_ORDER
);
110 static inline void free_thread_info(struct thread_info
*ti
)
112 free_pages((unsigned long)ti
, THREAD_SIZE_ORDER
);
116 /* SLAB cache for signal_struct structures (tsk->signal) */
117 static struct kmem_cache
*signal_cachep
;
119 /* SLAB cache for sighand_struct structures (tsk->sighand) */
120 struct kmem_cache
*sighand_cachep
;
122 /* SLAB cache for files_struct structures (tsk->files) */
123 struct kmem_cache
*files_cachep
;
125 /* SLAB cache for fs_struct structures (tsk->fs) */
126 struct kmem_cache
*fs_cachep
;
128 /* SLAB cache for vm_area_struct structures */
129 struct kmem_cache
*vm_area_cachep
;
131 /* SLAB cache for mm_struct structures (tsk->mm) */
132 static struct kmem_cache
*mm_cachep
;
134 void free_task(struct task_struct
*tsk
)
136 prop_local_destroy_single(&tsk
->dirties
);
137 free_thread_info(tsk
->stack
);
138 rt_mutex_debug_task_free(tsk
);
139 free_task_struct(tsk
);
141 EXPORT_SYMBOL(free_task
);
143 void __put_task_struct(struct task_struct
*tsk
)
145 WARN_ON(!tsk
->exit_state
);
146 WARN_ON(atomic_read(&tsk
->usage
));
147 WARN_ON(tsk
== current
);
150 delayacct_tsk_free(tsk
);
152 if (!profile_handoff_task(tsk
))
157 * macro override instead of weak attribute alias, to workaround
158 * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
160 #ifndef arch_task_cache_init
161 #define arch_task_cache_init()
164 void __init
fork_init(unsigned long mempages
)
166 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
167 #ifndef ARCH_MIN_TASKALIGN
168 #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
170 /* create a slab on which task_structs can be allocated */
172 kmem_cache_create("task_struct", sizeof(struct task_struct
),
173 ARCH_MIN_TASKALIGN
, SLAB_PANIC
, NULL
);
176 /* do the arch specific task caches init */
177 arch_task_cache_init();
180 * The default maximum number of threads is set to a safe
181 * value: the thread structures can take up at most half
184 max_threads
= mempages
/ (8 * THREAD_SIZE
/ PAGE_SIZE
);
187 * we need to allow at least 20 threads to boot a system
192 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_cur
= max_threads
/2;
193 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_max
= max_threads
/2;
194 init_task
.signal
->rlim
[RLIMIT_SIGPENDING
] =
195 init_task
.signal
->rlim
[RLIMIT_NPROC
];
198 int __attribute__((weak
)) arch_dup_task_struct(struct task_struct
*dst
,
199 struct task_struct
*src
)
205 static struct task_struct
*dup_task_struct(struct task_struct
*orig
)
207 struct task_struct
*tsk
;
208 struct thread_info
*ti
;
211 prepare_to_copy(orig
);
213 tsk
= alloc_task_struct();
217 ti
= alloc_thread_info(tsk
);
219 free_task_struct(tsk
);
223 err
= arch_dup_task_struct(tsk
, orig
);
229 err
= prop_local_init_single(&tsk
->dirties
);
233 setup_thread_stack(tsk
, orig
);
235 #ifdef CONFIG_CC_STACKPROTECTOR
236 tsk
->stack_canary
= get_random_int();
239 /* One for us, one for whoever does the "release_task()" (usually parent) */
240 atomic_set(&tsk
->usage
,2);
241 atomic_set(&tsk
->fs_excl
, 0);
242 #ifdef CONFIG_BLK_DEV_IO_TRACE
245 tsk
->splice_pipe
= NULL
;
249 free_thread_info(ti
);
250 free_task_struct(tsk
);
255 static int dup_mmap(struct mm_struct
*mm
, struct mm_struct
*oldmm
)
257 struct vm_area_struct
*mpnt
, *tmp
, **pprev
;
258 struct rb_node
**rb_link
, *rb_parent
;
260 unsigned long charge
;
261 struct mempolicy
*pol
;
263 down_write(&oldmm
->mmap_sem
);
264 flush_cache_dup_mm(oldmm
);
266 * Not linked in yet - no deadlock potential:
268 down_write_nested(&mm
->mmap_sem
, SINGLE_DEPTH_NESTING
);
272 mm
->mmap_cache
= NULL
;
273 mm
->free_area_cache
= oldmm
->mmap_base
;
274 mm
->cached_hole_size
= ~0UL;
276 cpus_clear(mm
->cpu_vm_mask
);
278 rb_link
= &mm
->mm_rb
.rb_node
;
282 for (mpnt
= oldmm
->mmap
; mpnt
; mpnt
= mpnt
->vm_next
) {
285 if (mpnt
->vm_flags
& VM_DONTCOPY
) {
286 long pages
= vma_pages(mpnt
);
287 mm
->total_vm
-= pages
;
288 vm_stat_account(mm
, mpnt
->vm_flags
, mpnt
->vm_file
,
293 if (mpnt
->vm_flags
& VM_ACCOUNT
) {
294 unsigned int len
= (mpnt
->vm_end
- mpnt
->vm_start
) >> PAGE_SHIFT
;
295 if (security_vm_enough_memory(len
))
299 tmp
= kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
303 pol
= mpol_dup(vma_policy(mpnt
));
304 retval
= PTR_ERR(pol
);
306 goto fail_nomem_policy
;
307 vma_set_policy(tmp
, pol
);
308 tmp
->vm_flags
&= ~VM_LOCKED
;
314 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
316 if (tmp
->vm_flags
& VM_DENYWRITE
)
317 atomic_dec(&inode
->i_writecount
);
319 /* insert tmp into the share list, just after mpnt */
320 spin_lock(&file
->f_mapping
->i_mmap_lock
);
321 tmp
->vm_truncate_count
= mpnt
->vm_truncate_count
;
322 flush_dcache_mmap_lock(file
->f_mapping
);
323 vma_prio_tree_add(tmp
, mpnt
);
324 flush_dcache_mmap_unlock(file
->f_mapping
);
325 spin_unlock(&file
->f_mapping
->i_mmap_lock
);
329 * Clear hugetlb-related page reserves for children. This only
330 * affects MAP_PRIVATE mappings. Faults generated by the child
331 * are not guaranteed to succeed, even if read-only
333 if (is_vm_hugetlb_page(tmp
))
334 reset_vma_resv_huge_pages(tmp
);
337 * Link in the new vma and copy the page table entries.
340 pprev
= &tmp
->vm_next
;
342 __vma_link_rb(mm
, tmp
, rb_link
, rb_parent
);
343 rb_link
= &tmp
->vm_rb
.rb_right
;
344 rb_parent
= &tmp
->vm_rb
;
347 retval
= copy_page_range(mm
, oldmm
, mpnt
);
349 if (tmp
->vm_ops
&& tmp
->vm_ops
->open
)
350 tmp
->vm_ops
->open(tmp
);
355 /* a new mm has just been created */
356 arch_dup_mmap(oldmm
, mm
);
359 up_write(&mm
->mmap_sem
);
361 up_write(&oldmm
->mmap_sem
);
364 kmem_cache_free(vm_area_cachep
, tmp
);
367 vm_unacct_memory(charge
);
371 static inline int mm_alloc_pgd(struct mm_struct
* mm
)
373 mm
->pgd
= pgd_alloc(mm
);
374 if (unlikely(!mm
->pgd
))
379 static inline void mm_free_pgd(struct mm_struct
* mm
)
381 pgd_free(mm
, mm
->pgd
);
384 #define dup_mmap(mm, oldmm) (0)
385 #define mm_alloc_pgd(mm) (0)
386 #define mm_free_pgd(mm)
387 #endif /* CONFIG_MMU */
389 __cacheline_aligned_in_smp
DEFINE_SPINLOCK(mmlist_lock
);
391 #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
392 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
394 #include <linux/init_task.h>
396 static struct mm_struct
* mm_init(struct mm_struct
* mm
, struct task_struct
*p
)
398 atomic_set(&mm
->mm_users
, 1);
399 atomic_set(&mm
->mm_count
, 1);
400 init_rwsem(&mm
->mmap_sem
);
401 INIT_LIST_HEAD(&mm
->mmlist
);
402 mm
->flags
= (current
->mm
) ? current
->mm
->flags
403 : MMF_DUMP_FILTER_DEFAULT
;
404 mm
->core_state
= NULL
;
406 set_mm_counter(mm
, file_rss
, 0);
407 set_mm_counter(mm
, anon_rss
, 0);
408 spin_lock_init(&mm
->page_table_lock
);
409 rwlock_init(&mm
->ioctx_list_lock
);
410 mm
->ioctx_list
= NULL
;
411 mm
->free_area_cache
= TASK_UNMAPPED_BASE
;
412 mm
->cached_hole_size
= ~0UL;
413 mm_init_owner(mm
, p
);
415 if (likely(!mm_alloc_pgd(mm
))) {
417 mmu_notifier_mm_init(mm
);
426 * Allocate and initialize an mm_struct.
428 struct mm_struct
* mm_alloc(void)
430 struct mm_struct
* mm
;
434 memset(mm
, 0, sizeof(*mm
));
435 mm
= mm_init(mm
, current
);
441 * Called when the last reference to the mm
442 * is dropped: either by a lazy thread or by
443 * mmput. Free the page directory and the mm.
445 void __mmdrop(struct mm_struct
*mm
)
447 BUG_ON(mm
== &init_mm
);
450 mmu_notifier_mm_destroy(mm
);
453 EXPORT_SYMBOL_GPL(__mmdrop
);
456 * Decrement the use count and release all resources for an mm.
458 void mmput(struct mm_struct
*mm
)
462 if (atomic_dec_and_test(&mm
->mm_users
)) {
465 set_mm_exe_file(mm
, NULL
);
466 if (!list_empty(&mm
->mmlist
)) {
467 spin_lock(&mmlist_lock
);
468 list_del(&mm
->mmlist
);
469 spin_unlock(&mmlist_lock
);
475 EXPORT_SYMBOL_GPL(mmput
);
478 * get_task_mm - acquire a reference to the task's mm
480 * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
481 * this kernel workthread has transiently adopted a user mm with use_mm,
482 * to do its AIO) is not set and if so returns a reference to it, after
483 * bumping up the use count. User must release the mm via mmput()
484 * after use. Typically used by /proc and ptrace.
486 struct mm_struct
*get_task_mm(struct task_struct
*task
)
488 struct mm_struct
*mm
;
493 if (task
->flags
& PF_KTHREAD
)
496 atomic_inc(&mm
->mm_users
);
501 EXPORT_SYMBOL_GPL(get_task_mm
);
503 /* Please note the differences between mmput and mm_release.
504 * mmput is called whenever we stop holding onto a mm_struct,
505 * error success whatever.
507 * mm_release is called after a mm_struct has been removed
508 * from the current process.
510 * This difference is important for error handling, when we
511 * only half set up a mm_struct for a new process and need to restore
512 * the old one. Because we mmput the new mm_struct before
513 * restoring the old one. . .
514 * Eric Biederman 10 January 1998
516 void mm_release(struct task_struct
*tsk
, struct mm_struct
*mm
)
518 struct completion
*vfork_done
= tsk
->vfork_done
;
520 /* Get rid of any cached register state */
521 deactivate_mm(tsk
, mm
);
523 /* notify parent sleeping on vfork() */
525 tsk
->vfork_done
= NULL
;
526 complete(vfork_done
);
530 * If we're exiting normally, clear a user-space tid field if
531 * requested. We leave this alone when dying by signal, to leave
532 * the value intact in a core dump, and to save the unnecessary
533 * trouble otherwise. Userland only wants this done for a sys_exit.
535 if (tsk
->clear_child_tid
536 && !(tsk
->flags
& PF_SIGNALED
)
537 && atomic_read(&mm
->mm_users
) > 1) {
538 u32 __user
* tidptr
= tsk
->clear_child_tid
;
539 tsk
->clear_child_tid
= NULL
;
542 * We don't check the error code - if userspace has
543 * not set up a proper pointer then tough luck.
546 sys_futex(tidptr
, FUTEX_WAKE
, 1, NULL
, NULL
, 0);
551 * Allocate a new mm structure and copy contents from the
552 * mm structure of the passed in task structure.
554 struct mm_struct
*dup_mm(struct task_struct
*tsk
)
556 struct mm_struct
*mm
, *oldmm
= current
->mm
;
566 memcpy(mm
, oldmm
, sizeof(*mm
));
568 /* Initializing for Swap token stuff */
569 mm
->token_priority
= 0;
570 mm
->last_interval
= 0;
572 if (!mm_init(mm
, tsk
))
575 if (init_new_context(tsk
, mm
))
578 dup_mm_exe_file(oldmm
, mm
);
580 err
= dup_mmap(mm
, oldmm
);
584 mm
->hiwater_rss
= get_mm_rss(mm
);
585 mm
->hiwater_vm
= mm
->total_vm
;
597 * If init_new_context() failed, we cannot use mmput() to free the mm
598 * because it calls destroy_context()
605 static int copy_mm(unsigned long clone_flags
, struct task_struct
* tsk
)
607 struct mm_struct
* mm
, *oldmm
;
610 tsk
->min_flt
= tsk
->maj_flt
= 0;
611 tsk
->nvcsw
= tsk
->nivcsw
= 0;
614 tsk
->active_mm
= NULL
;
617 * Are we cloning a kernel thread?
619 * We need to steal a active VM for that..
625 if (clone_flags
& CLONE_VM
) {
626 atomic_inc(&oldmm
->mm_users
);
637 /* Initializing for Swap token stuff */
638 mm
->token_priority
= 0;
639 mm
->last_interval
= 0;
649 static struct fs_struct
*__copy_fs_struct(struct fs_struct
*old
)
651 struct fs_struct
*fs
= kmem_cache_alloc(fs_cachep
, GFP_KERNEL
);
652 /* We don't need to lock fs - think why ;-) */
654 atomic_set(&fs
->count
, 1);
655 rwlock_init(&fs
->lock
);
656 fs
->umask
= old
->umask
;
657 read_lock(&old
->lock
);
658 fs
->root
= old
->root
;
659 path_get(&old
->root
);
662 read_unlock(&old
->lock
);
667 struct fs_struct
*copy_fs_struct(struct fs_struct
*old
)
669 return __copy_fs_struct(old
);
672 EXPORT_SYMBOL_GPL(copy_fs_struct
);
674 static int copy_fs(unsigned long clone_flags
, struct task_struct
*tsk
)
676 if (clone_flags
& CLONE_FS
) {
677 atomic_inc(¤t
->fs
->count
);
680 tsk
->fs
= __copy_fs_struct(current
->fs
);
686 static int copy_files(unsigned long clone_flags
, struct task_struct
* tsk
)
688 struct files_struct
*oldf
, *newf
;
692 * A background process may not have any files ...
694 oldf
= current
->files
;
698 if (clone_flags
& CLONE_FILES
) {
699 atomic_inc(&oldf
->count
);
703 newf
= dup_fd(oldf
, &error
);
713 static int copy_io(unsigned long clone_flags
, struct task_struct
*tsk
)
716 struct io_context
*ioc
= current
->io_context
;
721 * Share io context with parent, if CLONE_IO is set
723 if (clone_flags
& CLONE_IO
) {
724 tsk
->io_context
= ioc_task_link(ioc
);
725 if (unlikely(!tsk
->io_context
))
727 } else if (ioprio_valid(ioc
->ioprio
)) {
728 tsk
->io_context
= alloc_io_context(GFP_KERNEL
, -1);
729 if (unlikely(!tsk
->io_context
))
732 tsk
->io_context
->ioprio
= ioc
->ioprio
;
738 static int copy_sighand(unsigned long clone_flags
, struct task_struct
*tsk
)
740 struct sighand_struct
*sig
;
742 if (clone_flags
& (CLONE_SIGHAND
| CLONE_THREAD
)) {
743 atomic_inc(¤t
->sighand
->count
);
746 sig
= kmem_cache_alloc(sighand_cachep
, GFP_KERNEL
);
747 rcu_assign_pointer(tsk
->sighand
, sig
);
750 atomic_set(&sig
->count
, 1);
751 memcpy(sig
->action
, current
->sighand
->action
, sizeof(sig
->action
));
755 void __cleanup_sighand(struct sighand_struct
*sighand
)
757 if (atomic_dec_and_test(&sighand
->count
))
758 kmem_cache_free(sighand_cachep
, sighand
);
763 * Initialize POSIX timer handling for a thread group.
765 static void posix_cpu_timers_init_group(struct signal_struct
*sig
)
767 /* Thread group counters. */
768 thread_group_cputime_init(sig
);
770 /* Expiration times and increments. */
771 sig
->it_virt_expires
= cputime_zero
;
772 sig
->it_virt_incr
= cputime_zero
;
773 sig
->it_prof_expires
= cputime_zero
;
774 sig
->it_prof_incr
= cputime_zero
;
776 /* Cached expiration times. */
777 sig
->cputime_expires
.prof_exp
= cputime_zero
;
778 sig
->cputime_expires
.virt_exp
= cputime_zero
;
779 sig
->cputime_expires
.sched_exp
= 0;
781 /* The timer lists. */
782 INIT_LIST_HEAD(&sig
->cpu_timers
[0]);
783 INIT_LIST_HEAD(&sig
->cpu_timers
[1]);
784 INIT_LIST_HEAD(&sig
->cpu_timers
[2]);
787 static int copy_signal(unsigned long clone_flags
, struct task_struct
*tsk
)
789 struct signal_struct
*sig
;
792 if (clone_flags
& CLONE_THREAD
) {
793 ret
= thread_group_cputime_clone_thread(current
);
795 atomic_inc(¤t
->signal
->count
);
796 atomic_inc(¤t
->signal
->live
);
800 sig
= kmem_cache_alloc(signal_cachep
, GFP_KERNEL
);
805 atomic_set(&sig
->count
, 1);
806 atomic_set(&sig
->live
, 1);
807 init_waitqueue_head(&sig
->wait_chldexit
);
809 sig
->group_exit_code
= 0;
810 sig
->group_exit_task
= NULL
;
811 sig
->group_stop_count
= 0;
812 sig
->curr_target
= tsk
;
813 init_sigpending(&sig
->shared_pending
);
814 INIT_LIST_HEAD(&sig
->posix_timers
);
816 hrtimer_init(&sig
->real_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
817 sig
->it_real_incr
.tv64
= 0;
818 sig
->real_timer
.function
= it_real_fn
;
820 sig
->leader
= 0; /* session leadership doesn't inherit */
821 sig
->tty_old_pgrp
= NULL
;
824 sig
->cutime
= sig
->cstime
= cputime_zero
;
825 sig
->gtime
= cputime_zero
;
826 sig
->cgtime
= cputime_zero
;
827 sig
->nvcsw
= sig
->nivcsw
= sig
->cnvcsw
= sig
->cnivcsw
= 0;
828 sig
->min_flt
= sig
->maj_flt
= sig
->cmin_flt
= sig
->cmaj_flt
= 0;
829 sig
->inblock
= sig
->oublock
= sig
->cinblock
= sig
->coublock
= 0;
830 task_io_accounting_init(&sig
->ioac
);
831 taskstats_tgid_init(sig
);
833 task_lock(current
->group_leader
);
834 memcpy(sig
->rlim
, current
->signal
->rlim
, sizeof sig
->rlim
);
835 task_unlock(current
->group_leader
);
837 posix_cpu_timers_init_group(sig
);
839 acct_init_pacct(&sig
->pacct
);
846 void __cleanup_signal(struct signal_struct
*sig
)
848 thread_group_cputime_free(sig
);
849 tty_kref_put(sig
->tty
);
850 kmem_cache_free(signal_cachep
, sig
);
853 static void cleanup_signal(struct task_struct
*tsk
)
855 struct signal_struct
*sig
= tsk
->signal
;
857 atomic_dec(&sig
->live
);
859 if (atomic_dec_and_test(&sig
->count
))
860 __cleanup_signal(sig
);
863 static void copy_flags(unsigned long clone_flags
, struct task_struct
*p
)
865 unsigned long new_flags
= p
->flags
;
867 new_flags
&= ~PF_SUPERPRIV
;
868 new_flags
|= PF_FORKNOEXEC
;
869 new_flags
|= PF_STARTING
;
870 p
->flags
= new_flags
;
871 clear_freeze_flag(p
);
874 asmlinkage
long sys_set_tid_address(int __user
*tidptr
)
876 current
->clear_child_tid
= tidptr
;
878 return task_pid_vnr(current
);
881 static void rt_mutex_init_task(struct task_struct
*p
)
883 spin_lock_init(&p
->pi_lock
);
884 #ifdef CONFIG_RT_MUTEXES
885 plist_head_init(&p
->pi_waiters
, &p
->pi_lock
);
886 p
->pi_blocked_on
= NULL
;
890 #ifdef CONFIG_MM_OWNER
891 void mm_init_owner(struct mm_struct
*mm
, struct task_struct
*p
)
895 #endif /* CONFIG_MM_OWNER */
898 * Initialize POSIX timer handling for a single task.
900 static void posix_cpu_timers_init(struct task_struct
*tsk
)
902 tsk
->cputime_expires
.prof_exp
= cputime_zero
;
903 tsk
->cputime_expires
.virt_exp
= cputime_zero
;
904 tsk
->cputime_expires
.sched_exp
= 0;
905 INIT_LIST_HEAD(&tsk
->cpu_timers
[0]);
906 INIT_LIST_HEAD(&tsk
->cpu_timers
[1]);
907 INIT_LIST_HEAD(&tsk
->cpu_timers
[2]);
911 * This creates a new process as a copy of the old one,
912 * but does not actually start it yet.
914 * It copies the registers, and all the appropriate
915 * parts of the process environment (as per the clone
916 * flags). The actual kick-off is left to the caller.
918 static struct task_struct
*copy_process(unsigned long clone_flags
,
919 unsigned long stack_start
,
920 struct pt_regs
*regs
,
921 unsigned long stack_size
,
922 int __user
*child_tidptr
,
927 struct task_struct
*p
;
928 int cgroup_callbacks_done
= 0;
930 if ((clone_flags
& (CLONE_NEWNS
|CLONE_FS
)) == (CLONE_NEWNS
|CLONE_FS
))
931 return ERR_PTR(-EINVAL
);
934 * Thread groups must share signals as well, and detached threads
935 * can only be started up within the thread group.
937 if ((clone_flags
& CLONE_THREAD
) && !(clone_flags
& CLONE_SIGHAND
))
938 return ERR_PTR(-EINVAL
);
941 * Shared signal handlers imply shared VM. By way of the above,
942 * thread groups also imply shared VM. Blocking this case allows
943 * for various simplifications in other code.
945 if ((clone_flags
& CLONE_SIGHAND
) && !(clone_flags
& CLONE_VM
))
946 return ERR_PTR(-EINVAL
);
948 retval
= security_task_create(clone_flags
);
953 p
= dup_task_struct(current
);
957 rt_mutex_init_task(p
);
959 #ifdef CONFIG_PROVE_LOCKING
960 DEBUG_LOCKS_WARN_ON(!p
->hardirqs_enabled
);
961 DEBUG_LOCKS_WARN_ON(!p
->softirqs_enabled
);
964 if (atomic_read(&p
->cred
->user
->processes
) >=
965 p
->signal
->rlim
[RLIMIT_NPROC
].rlim_cur
) {
966 if (!capable(CAP_SYS_ADMIN
) && !capable(CAP_SYS_RESOURCE
) &&
967 p
->cred
->user
!= current
->nsproxy
->user_ns
->root_user
)
971 retval
= copy_creds(p
, clone_flags
);
976 * If multiple threads are within copy_process(), then this check
977 * triggers too late. This doesn't hurt, the check is only there
978 * to stop root fork bombs.
980 if (nr_threads
>= max_threads
)
981 goto bad_fork_cleanup_count
;
983 if (!try_module_get(task_thread_info(p
)->exec_domain
->module
))
984 goto bad_fork_cleanup_count
;
986 if (p
->binfmt
&& !try_module_get(p
->binfmt
->module
))
987 goto bad_fork_cleanup_put_domain
;
990 delayacct_tsk_init(p
); /* Must remain after dup_task_struct() */
991 copy_flags(clone_flags
, p
);
992 INIT_LIST_HEAD(&p
->children
);
993 INIT_LIST_HEAD(&p
->sibling
);
994 #ifdef CONFIG_PREEMPT_RCU
995 p
->rcu_read_lock_nesting
= 0;
996 p
->rcu_flipctr_idx
= 0;
997 #endif /* #ifdef CONFIG_PREEMPT_RCU */
998 p
->vfork_done
= NULL
;
999 spin_lock_init(&p
->alloc_lock
);
1001 clear_tsk_thread_flag(p
, TIF_SIGPENDING
);
1002 init_sigpending(&p
->pending
);
1004 p
->utime
= cputime_zero
;
1005 p
->stime
= cputime_zero
;
1006 p
->gtime
= cputime_zero
;
1007 p
->utimescaled
= cputime_zero
;
1008 p
->stimescaled
= cputime_zero
;
1009 p
->prev_utime
= cputime_zero
;
1010 p
->prev_stime
= cputime_zero
;
1012 p
->default_timer_slack_ns
= current
->timer_slack_ns
;
1014 #ifdef CONFIG_DETECT_SOFTLOCKUP
1015 p
->last_switch_count
= 0;
1016 p
->last_switch_timestamp
= 0;
1019 task_io_accounting_init(&p
->ioac
);
1020 acct_clear_integrals(p
);
1022 posix_cpu_timers_init(p
);
1024 p
->lock_depth
= -1; /* -1 = no lock */
1025 do_posix_clock_monotonic_gettime(&p
->start_time
);
1026 p
->real_start_time
= p
->start_time
;
1027 monotonic_to_bootbased(&p
->real_start_time
);
1028 p
->io_context
= NULL
;
1029 p
->audit_context
= NULL
;
1032 p
->mempolicy
= mpol_dup(p
->mempolicy
);
1033 if (IS_ERR(p
->mempolicy
)) {
1034 retval
= PTR_ERR(p
->mempolicy
);
1035 p
->mempolicy
= NULL
;
1036 goto bad_fork_cleanup_cgroup
;
1038 mpol_fix_fork_child_flag(p
);
1040 #ifdef CONFIG_TRACE_IRQFLAGS
1042 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1043 p
->hardirqs_enabled
= 1;
1045 p
->hardirqs_enabled
= 0;
1047 p
->hardirq_enable_ip
= 0;
1048 p
->hardirq_enable_event
= 0;
1049 p
->hardirq_disable_ip
= _THIS_IP_
;
1050 p
->hardirq_disable_event
= 0;
1051 p
->softirqs_enabled
= 1;
1052 p
->softirq_enable_ip
= _THIS_IP_
;
1053 p
->softirq_enable_event
= 0;
1054 p
->softirq_disable_ip
= 0;
1055 p
->softirq_disable_event
= 0;
1056 p
->hardirq_context
= 0;
1057 p
->softirq_context
= 0;
1059 #ifdef CONFIG_LOCKDEP
1060 p
->lockdep_depth
= 0; /* no locks held yet */
1061 p
->curr_chain_key
= 0;
1062 p
->lockdep_recursion
= 0;
1065 #ifdef CONFIG_DEBUG_MUTEXES
1066 p
->blocked_on
= NULL
; /* not blocked yet */
1069 /* Perform scheduler related setup. Assign this task to a CPU. */
1070 sched_fork(p
, clone_flags
);
1072 if ((retval
= audit_alloc(p
)))
1073 goto bad_fork_cleanup_policy
;
1074 /* copy all the process information */
1075 if ((retval
= copy_semundo(clone_flags
, p
)))
1076 goto bad_fork_cleanup_audit
;
1077 if ((retval
= copy_files(clone_flags
, p
)))
1078 goto bad_fork_cleanup_semundo
;
1079 if ((retval
= copy_fs(clone_flags
, p
)))
1080 goto bad_fork_cleanup_files
;
1081 if ((retval
= copy_sighand(clone_flags
, p
)))
1082 goto bad_fork_cleanup_fs
;
1083 if ((retval
= copy_signal(clone_flags
, p
)))
1084 goto bad_fork_cleanup_sighand
;
1085 if ((retval
= copy_mm(clone_flags
, p
)))
1086 goto bad_fork_cleanup_signal
;
1087 if ((retval
= copy_namespaces(clone_flags
, p
)))
1088 goto bad_fork_cleanup_mm
;
1089 if ((retval
= copy_io(clone_flags
, p
)))
1090 goto bad_fork_cleanup_namespaces
;
1091 retval
= copy_thread(0, clone_flags
, stack_start
, stack_size
, p
, regs
);
1093 goto bad_fork_cleanup_io
;
1095 if (pid
!= &init_struct_pid
) {
1097 pid
= alloc_pid(task_active_pid_ns(p
));
1099 goto bad_fork_cleanup_io
;
1101 if (clone_flags
& CLONE_NEWPID
) {
1102 retval
= pid_ns_prepare_proc(task_active_pid_ns(p
));
1104 goto bad_fork_free_pid
;
1108 p
->pid
= pid_nr(pid
);
1110 if (clone_flags
& CLONE_THREAD
)
1111 p
->tgid
= current
->tgid
;
1113 if (current
->nsproxy
!= p
->nsproxy
) {
1114 retval
= ns_cgroup_clone(p
, pid
);
1116 goto bad_fork_free_pid
;
1119 p
->set_child_tid
= (clone_flags
& CLONE_CHILD_SETTID
) ? child_tidptr
: NULL
;
1121 * Clear TID on mm_release()?
1123 p
->clear_child_tid
= (clone_flags
& CLONE_CHILD_CLEARTID
) ? child_tidptr
: NULL
;
1125 p
->robust_list
= NULL
;
1126 #ifdef CONFIG_COMPAT
1127 p
->compat_robust_list
= NULL
;
1129 INIT_LIST_HEAD(&p
->pi_state_list
);
1130 p
->pi_state_cache
= NULL
;
1133 * sigaltstack should be cleared when sharing the same VM
1135 if ((clone_flags
& (CLONE_VM
|CLONE_VFORK
)) == CLONE_VM
)
1136 p
->sas_ss_sp
= p
->sas_ss_size
= 0;
1139 * Syscall tracing should be turned off in the child regardless
1142 clear_tsk_thread_flag(p
, TIF_SYSCALL_TRACE
);
1143 #ifdef TIF_SYSCALL_EMU
1144 clear_tsk_thread_flag(p
, TIF_SYSCALL_EMU
);
1146 clear_all_latency_tracing(p
);
1148 /* Our parent execution domain becomes current domain
1149 These must match for thread signalling to apply */
1150 p
->parent_exec_id
= p
->self_exec_id
;
1152 /* ok, now we should be set up.. */
1153 p
->exit_signal
= (clone_flags
& CLONE_THREAD
) ? -1 : (clone_flags
& CSIGNAL
);
1154 p
->pdeath_signal
= 0;
1158 * Ok, make it visible to the rest of the system.
1159 * We dont wake it up yet.
1161 p
->group_leader
= p
;
1162 INIT_LIST_HEAD(&p
->thread_group
);
1164 /* Now that the task is set up, run cgroup callbacks if
1165 * necessary. We need to run them before the task is visible
1166 * on the tasklist. */
1167 cgroup_fork_callbacks(p
);
1168 cgroup_callbacks_done
= 1;
1170 /* Need tasklist lock for parent etc handling! */
1171 write_lock_irq(&tasklist_lock
);
1174 * The task hasn't been attached yet, so its cpus_allowed mask will
1175 * not be changed, nor will its assigned CPU.
1177 * The cpus_allowed mask of the parent may have changed after it was
1178 * copied first time - so re-copy it here, then check the child's CPU
1179 * to ensure it is on a valid CPU (and if not, just force it back to
1180 * parent's CPU). This avoids alot of nasty races.
1182 p
->cpus_allowed
= current
->cpus_allowed
;
1183 p
->rt
.nr_cpus_allowed
= current
->rt
.nr_cpus_allowed
;
1184 if (unlikely(!cpu_isset(task_cpu(p
), p
->cpus_allowed
) ||
1185 !cpu_online(task_cpu(p
))))
1186 set_task_cpu(p
, smp_processor_id());
1188 /* CLONE_PARENT re-uses the old parent */
1189 if (clone_flags
& (CLONE_PARENT
|CLONE_THREAD
))
1190 p
->real_parent
= current
->real_parent
;
1192 p
->real_parent
= current
;
1194 spin_lock(¤t
->sighand
->siglock
);
1197 * Process group and session signals need to be delivered to just the
1198 * parent before the fork or both the parent and the child after the
1199 * fork. Restart if a signal comes in before we add the new process to
1200 * it's process group.
1201 * A fatal signal pending means that current will exit, so the new
1202 * thread can't slip out of an OOM kill (or normal SIGKILL).
1204 recalc_sigpending();
1205 if (signal_pending(current
)) {
1206 spin_unlock(¤t
->sighand
->siglock
);
1207 write_unlock_irq(&tasklist_lock
);
1208 retval
= -ERESTARTNOINTR
;
1209 goto bad_fork_free_pid
;
1212 if (clone_flags
& CLONE_THREAD
) {
1213 p
->group_leader
= current
->group_leader
;
1214 list_add_tail_rcu(&p
->thread_group
, &p
->group_leader
->thread_group
);
1217 if (likely(p
->pid
)) {
1218 list_add_tail(&p
->sibling
, &p
->real_parent
->children
);
1219 tracehook_finish_clone(p
, clone_flags
, trace
);
1221 if (thread_group_leader(p
)) {
1222 if (clone_flags
& CLONE_NEWPID
)
1223 p
->nsproxy
->pid_ns
->child_reaper
= p
;
1225 p
->signal
->leader_pid
= pid
;
1226 tty_kref_put(p
->signal
->tty
);
1227 p
->signal
->tty
= tty_kref_get(current
->signal
->tty
);
1228 set_task_pgrp(p
, task_pgrp_nr(current
));
1229 set_task_session(p
, task_session_nr(current
));
1230 attach_pid(p
, PIDTYPE_PGID
, task_pgrp(current
));
1231 attach_pid(p
, PIDTYPE_SID
, task_session(current
));
1232 list_add_tail_rcu(&p
->tasks
, &init_task
.tasks
);
1233 __get_cpu_var(process_counts
)++;
1235 attach_pid(p
, PIDTYPE_PID
, pid
);
1240 spin_unlock(¤t
->sighand
->siglock
);
1241 write_unlock_irq(&tasklist_lock
);
1242 proc_fork_connector(p
);
1243 cgroup_post_fork(p
);
1247 if (pid
!= &init_struct_pid
)
1249 bad_fork_cleanup_io
:
1250 put_io_context(p
->io_context
);
1251 bad_fork_cleanup_namespaces
:
1252 exit_task_namespaces(p
);
1253 bad_fork_cleanup_mm
:
1256 bad_fork_cleanup_signal
:
1258 bad_fork_cleanup_sighand
:
1259 __cleanup_sighand(p
->sighand
);
1260 bad_fork_cleanup_fs
:
1261 exit_fs(p
); /* blocking */
1262 bad_fork_cleanup_files
:
1263 exit_files(p
); /* blocking */
1264 bad_fork_cleanup_semundo
:
1266 bad_fork_cleanup_audit
:
1268 bad_fork_cleanup_policy
:
1270 mpol_put(p
->mempolicy
);
1271 bad_fork_cleanup_cgroup
:
1273 cgroup_exit(p
, cgroup_callbacks_done
);
1274 delayacct_tsk_free(p
);
1276 module_put(p
->binfmt
->module
);
1277 bad_fork_cleanup_put_domain
:
1278 module_put(task_thread_info(p
)->exec_domain
->module
);
1279 bad_fork_cleanup_count
:
1280 atomic_dec(&p
->cred
->user
->processes
);
1285 return ERR_PTR(retval
);
1288 noinline
struct pt_regs
* __cpuinit
__attribute__((weak
)) idle_regs(struct pt_regs
*regs
)
1290 memset(regs
, 0, sizeof(struct pt_regs
));
1294 struct task_struct
* __cpuinit
fork_idle(int cpu
)
1296 struct task_struct
*task
;
1297 struct pt_regs regs
;
1299 task
= copy_process(CLONE_VM
, 0, idle_regs(®s
), 0, NULL
,
1300 &init_struct_pid
, 0);
1302 init_idle(task
, cpu
);
1308 * Ok, this is the main fork-routine.
1310 * It copies the process, and if successful kick-starts
1311 * it and waits for it to finish using the VM if required.
1313 long do_fork(unsigned long clone_flags
,
1314 unsigned long stack_start
,
1315 struct pt_regs
*regs
,
1316 unsigned long stack_size
,
1317 int __user
*parent_tidptr
,
1318 int __user
*child_tidptr
)
1320 struct task_struct
*p
;
1325 * We hope to recycle these flags after 2.6.26
1327 if (unlikely(clone_flags
& CLONE_STOPPED
)) {
1328 static int __read_mostly count
= 100;
1330 if (count
> 0 && printk_ratelimit()) {
1331 char comm
[TASK_COMM_LEN
];
1334 printk(KERN_INFO
"fork(): process `%s' used deprecated "
1335 "clone flags 0x%lx\n",
1336 get_task_comm(comm
, current
),
1337 clone_flags
& CLONE_STOPPED
);
1342 * When called from kernel_thread, don't do user tracing stuff.
1344 if (likely(user_mode(regs
)))
1345 trace
= tracehook_prepare_clone(clone_flags
);
1347 p
= copy_process(clone_flags
, stack_start
, regs
, stack_size
,
1348 child_tidptr
, NULL
, trace
);
1350 * Do this prior waking up the new thread - the thread pointer
1351 * might get invalid after that point, if the thread exits quickly.
1354 struct completion vfork
;
1356 trace_sched_process_fork(current
, p
);
1358 nr
= task_pid_vnr(p
);
1360 if (clone_flags
& CLONE_PARENT_SETTID
)
1361 put_user(nr
, parent_tidptr
);
1363 if (clone_flags
& CLONE_VFORK
) {
1364 p
->vfork_done
= &vfork
;
1365 init_completion(&vfork
);
1368 tracehook_report_clone(trace
, regs
, clone_flags
, nr
, p
);
1371 * We set PF_STARTING at creation in case tracing wants to
1372 * use this to distinguish a fully live task from one that
1373 * hasn't gotten to tracehook_report_clone() yet. Now we
1374 * clear it and set the child going.
1376 p
->flags
&= ~PF_STARTING
;
1378 if (unlikely(clone_flags
& CLONE_STOPPED
)) {
1380 * We'll start up with an immediate SIGSTOP.
1382 sigaddset(&p
->pending
.signal
, SIGSTOP
);
1383 set_tsk_thread_flag(p
, TIF_SIGPENDING
);
1384 __set_task_state(p
, TASK_STOPPED
);
1386 wake_up_new_task(p
, clone_flags
);
1389 tracehook_report_clone_complete(trace
, regs
,
1390 clone_flags
, nr
, p
);
1392 if (clone_flags
& CLONE_VFORK
) {
1393 freezer_do_not_count();
1394 wait_for_completion(&vfork
);
1396 tracehook_report_vfork_done(p
, nr
);
1404 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
1405 #define ARCH_MIN_MMSTRUCT_ALIGN 0
1408 static void sighand_ctor(void *data
)
1410 struct sighand_struct
*sighand
= data
;
1412 spin_lock_init(&sighand
->siglock
);
1413 init_waitqueue_head(&sighand
->signalfd_wqh
);
1416 void __init
proc_caches_init(void)
1418 sighand_cachep
= kmem_cache_create("sighand_cache",
1419 sizeof(struct sighand_struct
), 0,
1420 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_DESTROY_BY_RCU
,
1422 signal_cachep
= kmem_cache_create("signal_cache",
1423 sizeof(struct signal_struct
), 0,
1424 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1425 files_cachep
= kmem_cache_create("files_cache",
1426 sizeof(struct files_struct
), 0,
1427 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1428 fs_cachep
= kmem_cache_create("fs_cache",
1429 sizeof(struct fs_struct
), 0,
1430 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1431 vm_area_cachep
= kmem_cache_create("vm_area_struct",
1432 sizeof(struct vm_area_struct
), 0,
1434 mm_cachep
= kmem_cache_create("mm_struct",
1435 sizeof(struct mm_struct
), ARCH_MIN_MMSTRUCT_ALIGN
,
1436 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1440 * Check constraints on flags passed to the unshare system call and
1441 * force unsharing of additional process context as appropriate.
1443 static void check_unshare_flags(unsigned long *flags_ptr
)
1446 * If unsharing a thread from a thread group, must also
1449 if (*flags_ptr
& CLONE_THREAD
)
1450 *flags_ptr
|= CLONE_VM
;
1453 * If unsharing vm, must also unshare signal handlers.
1455 if (*flags_ptr
& CLONE_VM
)
1456 *flags_ptr
|= CLONE_SIGHAND
;
1459 * If unsharing signal handlers and the task was created
1460 * using CLONE_THREAD, then must unshare the thread
1462 if ((*flags_ptr
& CLONE_SIGHAND
) &&
1463 (atomic_read(¤t
->signal
->count
) > 1))
1464 *flags_ptr
|= CLONE_THREAD
;
1467 * If unsharing namespace, must also unshare filesystem information.
1469 if (*flags_ptr
& CLONE_NEWNS
)
1470 *flags_ptr
|= CLONE_FS
;
1474 * Unsharing of tasks created with CLONE_THREAD is not supported yet
1476 static int unshare_thread(unsigned long unshare_flags
)
1478 if (unshare_flags
& CLONE_THREAD
)
1485 * Unshare the filesystem structure if it is being shared
1487 static int unshare_fs(unsigned long unshare_flags
, struct fs_struct
**new_fsp
)
1489 struct fs_struct
*fs
= current
->fs
;
1491 if ((unshare_flags
& CLONE_FS
) &&
1492 (fs
&& atomic_read(&fs
->count
) > 1)) {
1493 *new_fsp
= __copy_fs_struct(current
->fs
);
1502 * Unsharing of sighand is not supported yet
1504 static int unshare_sighand(unsigned long unshare_flags
, struct sighand_struct
**new_sighp
)
1506 struct sighand_struct
*sigh
= current
->sighand
;
1508 if ((unshare_flags
& CLONE_SIGHAND
) && atomic_read(&sigh
->count
) > 1)
1515 * Unshare vm if it is being shared
1517 static int unshare_vm(unsigned long unshare_flags
, struct mm_struct
**new_mmp
)
1519 struct mm_struct
*mm
= current
->mm
;
1521 if ((unshare_flags
& CLONE_VM
) &&
1522 (mm
&& atomic_read(&mm
->mm_users
) > 1)) {
1530 * Unshare file descriptor table if it is being shared
1532 static int unshare_fd(unsigned long unshare_flags
, struct files_struct
**new_fdp
)
1534 struct files_struct
*fd
= current
->files
;
1537 if ((unshare_flags
& CLONE_FILES
) &&
1538 (fd
&& atomic_read(&fd
->count
) > 1)) {
1539 *new_fdp
= dup_fd(fd
, &error
);
1548 * unshare allows a process to 'unshare' part of the process
1549 * context which was originally shared using clone. copy_*
1550 * functions used by do_fork() cannot be used here directly
1551 * because they modify an inactive task_struct that is being
1552 * constructed. Here we are modifying the current, active,
1555 asmlinkage
long sys_unshare(unsigned long unshare_flags
)
1558 struct fs_struct
*fs
, *new_fs
= NULL
;
1559 struct sighand_struct
*new_sigh
= NULL
;
1560 struct mm_struct
*mm
, *new_mm
= NULL
, *active_mm
= NULL
;
1561 struct files_struct
*fd
, *new_fd
= NULL
;
1562 struct nsproxy
*new_nsproxy
= NULL
;
1565 check_unshare_flags(&unshare_flags
);
1567 /* Return -EINVAL for all unsupported flags */
1569 if (unshare_flags
& ~(CLONE_THREAD
|CLONE_FS
|CLONE_NEWNS
|CLONE_SIGHAND
|
1570 CLONE_VM
|CLONE_FILES
|CLONE_SYSVSEM
|
1571 CLONE_NEWUTS
|CLONE_NEWIPC
|CLONE_NEWUSER
|
1573 goto bad_unshare_out
;
1576 * CLONE_NEWIPC must also detach from the undolist: after switching
1577 * to a new ipc namespace, the semaphore arrays from the old
1578 * namespace are unreachable.
1580 if (unshare_flags
& (CLONE_NEWIPC
|CLONE_SYSVSEM
))
1582 if ((err
= unshare_thread(unshare_flags
)))
1583 goto bad_unshare_out
;
1584 if ((err
= unshare_fs(unshare_flags
, &new_fs
)))
1585 goto bad_unshare_cleanup_thread
;
1586 if ((err
= unshare_sighand(unshare_flags
, &new_sigh
)))
1587 goto bad_unshare_cleanup_fs
;
1588 if ((err
= unshare_vm(unshare_flags
, &new_mm
)))
1589 goto bad_unshare_cleanup_sigh
;
1590 if ((err
= unshare_fd(unshare_flags
, &new_fd
)))
1591 goto bad_unshare_cleanup_vm
;
1592 if ((err
= unshare_nsproxy_namespaces(unshare_flags
, &new_nsproxy
,
1594 goto bad_unshare_cleanup_fd
;
1596 if (new_fs
|| new_mm
|| new_fd
|| do_sysvsem
|| new_nsproxy
) {
1599 * CLONE_SYSVSEM is equivalent to sys_exit().
1605 switch_task_namespaces(current
, new_nsproxy
);
1613 current
->fs
= new_fs
;
1619 active_mm
= current
->active_mm
;
1620 current
->mm
= new_mm
;
1621 current
->active_mm
= new_mm
;
1622 activate_mm(active_mm
, new_mm
);
1627 fd
= current
->files
;
1628 current
->files
= new_fd
;
1632 task_unlock(current
);
1636 put_nsproxy(new_nsproxy
);
1638 bad_unshare_cleanup_fd
:
1640 put_files_struct(new_fd
);
1642 bad_unshare_cleanup_vm
:
1646 bad_unshare_cleanup_sigh
:
1648 if (atomic_dec_and_test(&new_sigh
->count
))
1649 kmem_cache_free(sighand_cachep
, new_sigh
);
1651 bad_unshare_cleanup_fs
:
1653 put_fs_struct(new_fs
);
1655 bad_unshare_cleanup_thread
:
1661 * Helper to unshare the files of the current task.
1662 * We don't want to expose copy_files internals to
1663 * the exec layer of the kernel.
1666 int unshare_files(struct files_struct
**displaced
)
1668 struct task_struct
*task
= current
;
1669 struct files_struct
*copy
= NULL
;
1672 error
= unshare_fd(CLONE_FILES
, ©
);
1673 if (error
|| !copy
) {
1677 *displaced
= task
->files
;