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/key.h>
27 #include <linux/binfmts.h>
28 #include <linux/mman.h>
30 #include <linux/nsproxy.h>
31 #include <linux/capability.h>
32 #include <linux/cpu.h>
33 #include <linux/cgroup.h>
34 #include <linux/security.h>
35 #include <linux/swap.h>
36 #include <linux/syscalls.h>
37 #include <linux/jiffies.h>
38 #include <linux/futex.h>
39 #include <linux/task_io_accounting_ops.h>
40 #include <linux/rcupdate.h>
41 #include <linux/ptrace.h>
42 #include <linux/mount.h>
43 #include <linux/audit.h>
44 #include <linux/memcontrol.h>
45 #include <linux/profile.h>
46 #include <linux/rmap.h>
47 #include <linux/acct.h>
48 #include <linux/tsacct_kern.h>
49 #include <linux/cn_proc.h>
50 #include <linux/freezer.h>
51 #include <linux/delayacct.h>
52 #include <linux/taskstats_kern.h>
53 #include <linux/random.h>
54 #include <linux/tty.h>
55 #include <linux/proc_fs.h>
56 #include <linux/blkdev.h>
58 #include <asm/pgtable.h>
59 #include <asm/pgalloc.h>
60 #include <asm/uaccess.h>
61 #include <asm/mmu_context.h>
62 #include <asm/cacheflush.h>
63 #include <asm/tlbflush.h>
66 * Protected counters by write_lock_irq(&tasklist_lock)
68 unsigned long total_forks
; /* Handle normal Linux uptimes. */
69 int nr_threads
; /* The idle threads do not count.. */
71 int max_threads
; /* tunable limit on nr_threads */
73 DEFINE_PER_CPU(unsigned long, process_counts
) = 0;
75 __cacheline_aligned
DEFINE_RWLOCK(tasklist_lock
); /* outer */
77 int nr_processes(void)
82 for_each_online_cpu(cpu
)
83 total
+= per_cpu(process_counts
, cpu
);
88 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
89 # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
90 # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk))
91 static struct kmem_cache
*task_struct_cachep
;
94 /* SLAB cache for signal_struct structures (tsk->signal) */
95 static struct kmem_cache
*signal_cachep
;
97 /* SLAB cache for sighand_struct structures (tsk->sighand) */
98 struct kmem_cache
*sighand_cachep
;
100 /* SLAB cache for files_struct structures (tsk->files) */
101 struct kmem_cache
*files_cachep
;
103 /* SLAB cache for fs_struct structures (tsk->fs) */
104 struct kmem_cache
*fs_cachep
;
106 /* SLAB cache for vm_area_struct structures */
107 struct kmem_cache
*vm_area_cachep
;
109 /* SLAB cache for mm_struct structures (tsk->mm) */
110 static struct kmem_cache
*mm_cachep
;
112 void free_task(struct task_struct
*tsk
)
114 prop_local_destroy_single(&tsk
->dirties
);
115 free_thread_info(tsk
->stack
);
116 rt_mutex_debug_task_free(tsk
);
117 free_task_struct(tsk
);
119 EXPORT_SYMBOL(free_task
);
121 void __put_task_struct(struct task_struct
*tsk
)
123 WARN_ON(!tsk
->exit_state
);
124 WARN_ON(atomic_read(&tsk
->usage
));
125 WARN_ON(tsk
== current
);
127 security_task_free(tsk
);
129 put_group_info(tsk
->group_info
);
130 delayacct_tsk_free(tsk
);
132 if (!profile_handoff_task(tsk
))
137 * macro override instead of weak attribute alias, to workaround
138 * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
140 #ifndef arch_task_cache_init
141 #define arch_task_cache_init()
144 void __init
fork_init(unsigned long mempages
)
146 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
147 #ifndef ARCH_MIN_TASKALIGN
148 #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
150 /* create a slab on which task_structs can be allocated */
152 kmem_cache_create("task_struct", sizeof(struct task_struct
),
153 ARCH_MIN_TASKALIGN
, SLAB_PANIC
, NULL
);
156 /* do the arch specific task caches init */
157 arch_task_cache_init();
160 * The default maximum number of threads is set to a safe
161 * value: the thread structures can take up at most half
164 max_threads
= mempages
/ (8 * THREAD_SIZE
/ PAGE_SIZE
);
167 * we need to allow at least 20 threads to boot a system
172 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_cur
= max_threads
/2;
173 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_max
= max_threads
/2;
174 init_task
.signal
->rlim
[RLIMIT_SIGPENDING
] =
175 init_task
.signal
->rlim
[RLIMIT_NPROC
];
178 int __attribute__((weak
)) arch_dup_task_struct(struct task_struct
*dst
,
179 struct task_struct
*src
)
185 static struct task_struct
*dup_task_struct(struct task_struct
*orig
)
187 struct task_struct
*tsk
;
188 struct thread_info
*ti
;
191 prepare_to_copy(orig
);
193 tsk
= alloc_task_struct();
197 ti
= alloc_thread_info(tsk
);
199 free_task_struct(tsk
);
203 err
= arch_dup_task_struct(tsk
, orig
);
209 err
= prop_local_init_single(&tsk
->dirties
);
213 setup_thread_stack(tsk
, orig
);
215 #ifdef CONFIG_CC_STACKPROTECTOR
216 tsk
->stack_canary
= get_random_int();
219 /* One for us, one for whoever does the "release_task()" (usually parent) */
220 atomic_set(&tsk
->usage
,2);
221 atomic_set(&tsk
->fs_excl
, 0);
222 #ifdef CONFIG_BLK_DEV_IO_TRACE
225 tsk
->splice_pipe
= NULL
;
229 free_thread_info(ti
);
230 free_task_struct(tsk
);
235 static int dup_mmap(struct mm_struct
*mm
, struct mm_struct
*oldmm
)
237 struct vm_area_struct
*mpnt
, *tmp
, **pprev
;
238 struct rb_node
**rb_link
, *rb_parent
;
240 unsigned long charge
;
241 struct mempolicy
*pol
;
243 down_write(&oldmm
->mmap_sem
);
244 flush_cache_dup_mm(oldmm
);
246 * Not linked in yet - no deadlock potential:
248 down_write_nested(&mm
->mmap_sem
, SINGLE_DEPTH_NESTING
);
252 mm
->mmap_cache
= NULL
;
253 mm
->free_area_cache
= oldmm
->mmap_base
;
254 mm
->cached_hole_size
= ~0UL;
256 cpus_clear(mm
->cpu_vm_mask
);
258 rb_link
= &mm
->mm_rb
.rb_node
;
262 for (mpnt
= oldmm
->mmap
; mpnt
; mpnt
= mpnt
->vm_next
) {
265 if (mpnt
->vm_flags
& VM_DONTCOPY
) {
266 long pages
= vma_pages(mpnt
);
267 mm
->total_vm
-= pages
;
268 vm_stat_account(mm
, mpnt
->vm_flags
, mpnt
->vm_file
,
273 if (mpnt
->vm_flags
& VM_ACCOUNT
) {
274 unsigned int len
= (mpnt
->vm_end
- mpnt
->vm_start
) >> PAGE_SHIFT
;
275 if (security_vm_enough_memory(len
))
279 tmp
= kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
283 pol
= mpol_dup(vma_policy(mpnt
));
284 retval
= PTR_ERR(pol
);
286 goto fail_nomem_policy
;
287 vma_set_policy(tmp
, pol
);
288 tmp
->vm_flags
&= ~VM_LOCKED
;
294 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
296 if (tmp
->vm_flags
& VM_DENYWRITE
)
297 atomic_dec(&inode
->i_writecount
);
299 /* insert tmp into the share list, just after mpnt */
300 spin_lock(&file
->f_mapping
->i_mmap_lock
);
301 tmp
->vm_truncate_count
= mpnt
->vm_truncate_count
;
302 flush_dcache_mmap_lock(file
->f_mapping
);
303 vma_prio_tree_add(tmp
, mpnt
);
304 flush_dcache_mmap_unlock(file
->f_mapping
);
305 spin_unlock(&file
->f_mapping
->i_mmap_lock
);
309 * Link in the new vma and copy the page table entries.
312 pprev
= &tmp
->vm_next
;
314 __vma_link_rb(mm
, tmp
, rb_link
, rb_parent
);
315 rb_link
= &tmp
->vm_rb
.rb_right
;
316 rb_parent
= &tmp
->vm_rb
;
319 retval
= copy_page_range(mm
, oldmm
, mpnt
);
321 if (tmp
->vm_ops
&& tmp
->vm_ops
->open
)
322 tmp
->vm_ops
->open(tmp
);
327 /* a new mm has just been created */
328 arch_dup_mmap(oldmm
, mm
);
331 up_write(&mm
->mmap_sem
);
333 up_write(&oldmm
->mmap_sem
);
336 kmem_cache_free(vm_area_cachep
, tmp
);
339 vm_unacct_memory(charge
);
343 static inline int mm_alloc_pgd(struct mm_struct
* mm
)
345 mm
->pgd
= pgd_alloc(mm
);
346 if (unlikely(!mm
->pgd
))
351 static inline void mm_free_pgd(struct mm_struct
* mm
)
353 pgd_free(mm
, mm
->pgd
);
356 #define dup_mmap(mm, oldmm) (0)
357 #define mm_alloc_pgd(mm) (0)
358 #define mm_free_pgd(mm)
359 #endif /* CONFIG_MMU */
361 __cacheline_aligned_in_smp
DEFINE_SPINLOCK(mmlist_lock
);
363 #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
364 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
366 #include <linux/init_task.h>
368 static struct mm_struct
* mm_init(struct mm_struct
* mm
, struct task_struct
*p
)
370 atomic_set(&mm
->mm_users
, 1);
371 atomic_set(&mm
->mm_count
, 1);
372 init_rwsem(&mm
->mmap_sem
);
373 INIT_LIST_HEAD(&mm
->mmlist
);
374 mm
->flags
= (current
->mm
) ? current
->mm
->flags
375 : MMF_DUMP_FILTER_DEFAULT
;
376 mm
->core_waiters
= 0;
378 set_mm_counter(mm
, file_rss
, 0);
379 set_mm_counter(mm
, anon_rss
, 0);
380 spin_lock_init(&mm
->page_table_lock
);
381 rwlock_init(&mm
->ioctx_list_lock
);
382 mm
->ioctx_list
= NULL
;
383 mm
->free_area_cache
= TASK_UNMAPPED_BASE
;
384 mm
->cached_hole_size
= ~0UL;
385 mm_init_owner(mm
, p
);
387 if (likely(!mm_alloc_pgd(mm
))) {
397 * Allocate and initialize an mm_struct.
399 struct mm_struct
* mm_alloc(void)
401 struct mm_struct
* mm
;
405 memset(mm
, 0, sizeof(*mm
));
406 mm
= mm_init(mm
, current
);
412 * Called when the last reference to the mm
413 * is dropped: either by a lazy thread or by
414 * mmput. Free the page directory and the mm.
416 void __mmdrop(struct mm_struct
*mm
)
418 BUG_ON(mm
== &init_mm
);
423 EXPORT_SYMBOL_GPL(__mmdrop
);
426 * Decrement the use count and release all resources for an mm.
428 void mmput(struct mm_struct
*mm
)
432 if (atomic_dec_and_test(&mm
->mm_users
)) {
435 set_mm_exe_file(mm
, NULL
);
436 if (!list_empty(&mm
->mmlist
)) {
437 spin_lock(&mmlist_lock
);
438 list_del(&mm
->mmlist
);
439 spin_unlock(&mmlist_lock
);
445 EXPORT_SYMBOL_GPL(mmput
);
448 * get_task_mm - acquire a reference to the task's mm
450 * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning
451 * this kernel workthread has transiently adopted a user mm with use_mm,
452 * to do its AIO) is not set and if so returns a reference to it, after
453 * bumping up the use count. User must release the mm via mmput()
454 * after use. Typically used by /proc and ptrace.
456 struct mm_struct
*get_task_mm(struct task_struct
*task
)
458 struct mm_struct
*mm
;
463 if (task
->flags
& PF_BORROWED_MM
)
466 atomic_inc(&mm
->mm_users
);
471 EXPORT_SYMBOL_GPL(get_task_mm
);
473 /* Please note the differences between mmput and mm_release.
474 * mmput is called whenever we stop holding onto a mm_struct,
475 * error success whatever.
477 * mm_release is called after a mm_struct has been removed
478 * from the current process.
480 * This difference is important for error handling, when we
481 * only half set up a mm_struct for a new process and need to restore
482 * the old one. Because we mmput the new mm_struct before
483 * restoring the old one. . .
484 * Eric Biederman 10 January 1998
486 void mm_release(struct task_struct
*tsk
, struct mm_struct
*mm
)
488 struct completion
*vfork_done
= tsk
->vfork_done
;
490 /* Get rid of any cached register state */
491 deactivate_mm(tsk
, mm
);
493 /* notify parent sleeping on vfork() */
495 tsk
->vfork_done
= NULL
;
496 complete(vfork_done
);
500 * If we're exiting normally, clear a user-space tid field if
501 * requested. We leave this alone when dying by signal, to leave
502 * the value intact in a core dump, and to save the unnecessary
503 * trouble otherwise. Userland only wants this done for a sys_exit.
505 if (tsk
->clear_child_tid
506 && !(tsk
->flags
& PF_SIGNALED
)
507 && atomic_read(&mm
->mm_users
) > 1) {
508 u32 __user
* tidptr
= tsk
->clear_child_tid
;
509 tsk
->clear_child_tid
= NULL
;
512 * We don't check the error code - if userspace has
513 * not set up a proper pointer then tough luck.
516 sys_futex(tidptr
, FUTEX_WAKE
, 1, NULL
, NULL
, 0);
521 * Allocate a new mm structure and copy contents from the
522 * mm structure of the passed in task structure.
524 struct mm_struct
*dup_mm(struct task_struct
*tsk
)
526 struct mm_struct
*mm
, *oldmm
= current
->mm
;
536 memcpy(mm
, oldmm
, sizeof(*mm
));
538 /* Initializing for Swap token stuff */
539 mm
->token_priority
= 0;
540 mm
->last_interval
= 0;
542 if (!mm_init(mm
, tsk
))
545 if (init_new_context(tsk
, mm
))
548 dup_mm_exe_file(oldmm
, mm
);
550 err
= dup_mmap(mm
, oldmm
);
554 mm
->hiwater_rss
= get_mm_rss(mm
);
555 mm
->hiwater_vm
= mm
->total_vm
;
567 * If init_new_context() failed, we cannot use mmput() to free the mm
568 * because it calls destroy_context()
575 static int copy_mm(unsigned long clone_flags
, struct task_struct
* tsk
)
577 struct mm_struct
* mm
, *oldmm
;
580 tsk
->min_flt
= tsk
->maj_flt
= 0;
581 tsk
->nvcsw
= tsk
->nivcsw
= 0;
584 tsk
->active_mm
= NULL
;
587 * Are we cloning a kernel thread?
589 * We need to steal a active VM for that..
595 if (clone_flags
& CLONE_VM
) {
596 atomic_inc(&oldmm
->mm_users
);
607 /* Initializing for Swap token stuff */
608 mm
->token_priority
= 0;
609 mm
->last_interval
= 0;
619 static struct fs_struct
*__copy_fs_struct(struct fs_struct
*old
)
621 struct fs_struct
*fs
= kmem_cache_alloc(fs_cachep
, GFP_KERNEL
);
622 /* We don't need to lock fs - think why ;-) */
624 atomic_set(&fs
->count
, 1);
625 rwlock_init(&fs
->lock
);
626 fs
->umask
= old
->umask
;
627 read_lock(&old
->lock
);
628 fs
->root
= old
->root
;
629 path_get(&old
->root
);
632 if (old
->altroot
.dentry
) {
633 fs
->altroot
= old
->altroot
;
634 path_get(&old
->altroot
);
636 fs
->altroot
.mnt
= NULL
;
637 fs
->altroot
.dentry
= NULL
;
639 read_unlock(&old
->lock
);
644 struct fs_struct
*copy_fs_struct(struct fs_struct
*old
)
646 return __copy_fs_struct(old
);
649 EXPORT_SYMBOL_GPL(copy_fs_struct
);
651 static int copy_fs(unsigned long clone_flags
, struct task_struct
*tsk
)
653 if (clone_flags
& CLONE_FS
) {
654 atomic_inc(¤t
->fs
->count
);
657 tsk
->fs
= __copy_fs_struct(current
->fs
);
663 static int copy_files(unsigned long clone_flags
, struct task_struct
* tsk
)
665 struct files_struct
*oldf
, *newf
;
669 * A background process may not have any files ...
671 oldf
= current
->files
;
675 if (clone_flags
& CLONE_FILES
) {
676 atomic_inc(&oldf
->count
);
680 newf
= dup_fd(oldf
, &error
);
690 static int copy_io(unsigned long clone_flags
, struct task_struct
*tsk
)
693 struct io_context
*ioc
= current
->io_context
;
698 * Share io context with parent, if CLONE_IO is set
700 if (clone_flags
& CLONE_IO
) {
701 tsk
->io_context
= ioc_task_link(ioc
);
702 if (unlikely(!tsk
->io_context
))
704 } else if (ioprio_valid(ioc
->ioprio
)) {
705 tsk
->io_context
= alloc_io_context(GFP_KERNEL
, -1);
706 if (unlikely(!tsk
->io_context
))
709 tsk
->io_context
->ioprio
= ioc
->ioprio
;
715 static int copy_sighand(unsigned long clone_flags
, struct task_struct
*tsk
)
717 struct sighand_struct
*sig
;
719 if (clone_flags
& (CLONE_SIGHAND
| CLONE_THREAD
)) {
720 atomic_inc(¤t
->sighand
->count
);
723 sig
= kmem_cache_alloc(sighand_cachep
, GFP_KERNEL
);
724 rcu_assign_pointer(tsk
->sighand
, sig
);
727 atomic_set(&sig
->count
, 1);
728 memcpy(sig
->action
, current
->sighand
->action
, sizeof(sig
->action
));
732 void __cleanup_sighand(struct sighand_struct
*sighand
)
734 if (atomic_dec_and_test(&sighand
->count
))
735 kmem_cache_free(sighand_cachep
, sighand
);
738 static int copy_signal(unsigned long clone_flags
, struct task_struct
*tsk
)
740 struct signal_struct
*sig
;
743 if (clone_flags
& CLONE_THREAD
) {
744 atomic_inc(¤t
->signal
->count
);
745 atomic_inc(¤t
->signal
->live
);
748 sig
= kmem_cache_alloc(signal_cachep
, GFP_KERNEL
);
753 ret
= copy_thread_group_keys(tsk
);
755 kmem_cache_free(signal_cachep
, sig
);
759 atomic_set(&sig
->count
, 1);
760 atomic_set(&sig
->live
, 1);
761 init_waitqueue_head(&sig
->wait_chldexit
);
763 sig
->group_exit_code
= 0;
764 sig
->group_exit_task
= NULL
;
765 sig
->group_stop_count
= 0;
766 sig
->curr_target
= tsk
;
767 init_sigpending(&sig
->shared_pending
);
768 INIT_LIST_HEAD(&sig
->posix_timers
);
770 hrtimer_init(&sig
->real_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
771 sig
->it_real_incr
.tv64
= 0;
772 sig
->real_timer
.function
= it_real_fn
;
774 sig
->it_virt_expires
= cputime_zero
;
775 sig
->it_virt_incr
= cputime_zero
;
776 sig
->it_prof_expires
= cputime_zero
;
777 sig
->it_prof_incr
= cputime_zero
;
779 sig
->leader
= 0; /* session leadership doesn't inherit */
780 sig
->tty_old_pgrp
= NULL
;
782 sig
->utime
= sig
->stime
= sig
->cutime
= sig
->cstime
= cputime_zero
;
783 sig
->gtime
= cputime_zero
;
784 sig
->cgtime
= cputime_zero
;
785 sig
->nvcsw
= sig
->nivcsw
= sig
->cnvcsw
= sig
->cnivcsw
= 0;
786 sig
->min_flt
= sig
->maj_flt
= sig
->cmin_flt
= sig
->cmaj_flt
= 0;
787 sig
->inblock
= sig
->oublock
= sig
->cinblock
= sig
->coublock
= 0;
788 sig
->sum_sched_runtime
= 0;
789 INIT_LIST_HEAD(&sig
->cpu_timers
[0]);
790 INIT_LIST_HEAD(&sig
->cpu_timers
[1]);
791 INIT_LIST_HEAD(&sig
->cpu_timers
[2]);
792 taskstats_tgid_init(sig
);
794 task_lock(current
->group_leader
);
795 memcpy(sig
->rlim
, current
->signal
->rlim
, sizeof sig
->rlim
);
796 task_unlock(current
->group_leader
);
798 if (sig
->rlim
[RLIMIT_CPU
].rlim_cur
!= RLIM_INFINITY
) {
800 * New sole thread in the process gets an expiry time
801 * of the whole CPU time limit.
803 tsk
->it_prof_expires
=
804 secs_to_cputime(sig
->rlim
[RLIMIT_CPU
].rlim_cur
);
806 acct_init_pacct(&sig
->pacct
);
813 void __cleanup_signal(struct signal_struct
*sig
)
815 exit_thread_group_keys(sig
);
816 kmem_cache_free(signal_cachep
, sig
);
819 static void cleanup_signal(struct task_struct
*tsk
)
821 struct signal_struct
*sig
= tsk
->signal
;
823 atomic_dec(&sig
->live
);
825 if (atomic_dec_and_test(&sig
->count
))
826 __cleanup_signal(sig
);
829 static void copy_flags(unsigned long clone_flags
, struct task_struct
*p
)
831 unsigned long new_flags
= p
->flags
;
833 new_flags
&= ~PF_SUPERPRIV
;
834 new_flags
|= PF_FORKNOEXEC
;
835 if (!(clone_flags
& CLONE_PTRACE
))
837 p
->flags
= new_flags
;
838 clear_freeze_flag(p
);
841 asmlinkage
long sys_set_tid_address(int __user
*tidptr
)
843 current
->clear_child_tid
= tidptr
;
845 return task_pid_vnr(current
);
848 static void rt_mutex_init_task(struct task_struct
*p
)
850 spin_lock_init(&p
->pi_lock
);
851 #ifdef CONFIG_RT_MUTEXES
852 plist_head_init(&p
->pi_waiters
, &p
->pi_lock
);
853 p
->pi_blocked_on
= NULL
;
857 #ifdef CONFIG_MM_OWNER
858 void mm_init_owner(struct mm_struct
*mm
, struct task_struct
*p
)
862 #endif /* CONFIG_MM_OWNER */
865 * This creates a new process as a copy of the old one,
866 * but does not actually start it yet.
868 * It copies the registers, and all the appropriate
869 * parts of the process environment (as per the clone
870 * flags). The actual kick-off is left to the caller.
872 static struct task_struct
*copy_process(unsigned long clone_flags
,
873 unsigned long stack_start
,
874 struct pt_regs
*regs
,
875 unsigned long stack_size
,
876 int __user
*child_tidptr
,
880 struct task_struct
*p
;
881 int cgroup_callbacks_done
= 0;
883 if ((clone_flags
& (CLONE_NEWNS
|CLONE_FS
)) == (CLONE_NEWNS
|CLONE_FS
))
884 return ERR_PTR(-EINVAL
);
887 * Thread groups must share signals as well, and detached threads
888 * can only be started up within the thread group.
890 if ((clone_flags
& CLONE_THREAD
) && !(clone_flags
& CLONE_SIGHAND
))
891 return ERR_PTR(-EINVAL
);
894 * Shared signal handlers imply shared VM. By way of the above,
895 * thread groups also imply shared VM. Blocking this case allows
896 * for various simplifications in other code.
898 if ((clone_flags
& CLONE_SIGHAND
) && !(clone_flags
& CLONE_VM
))
899 return ERR_PTR(-EINVAL
);
901 retval
= security_task_create(clone_flags
);
906 p
= dup_task_struct(current
);
910 rt_mutex_init_task(p
);
912 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_LOCKDEP)
913 DEBUG_LOCKS_WARN_ON(!p
->hardirqs_enabled
);
914 DEBUG_LOCKS_WARN_ON(!p
->softirqs_enabled
);
917 if (atomic_read(&p
->user
->processes
) >=
918 p
->signal
->rlim
[RLIMIT_NPROC
].rlim_cur
) {
919 if (!capable(CAP_SYS_ADMIN
) && !capable(CAP_SYS_RESOURCE
) &&
920 p
->user
!= current
->nsproxy
->user_ns
->root_user
)
924 atomic_inc(&p
->user
->__count
);
925 atomic_inc(&p
->user
->processes
);
926 get_group_info(p
->group_info
);
929 * If multiple threads are within copy_process(), then this check
930 * triggers too late. This doesn't hurt, the check is only there
931 * to stop root fork bombs.
933 if (nr_threads
>= max_threads
)
934 goto bad_fork_cleanup_count
;
936 if (!try_module_get(task_thread_info(p
)->exec_domain
->module
))
937 goto bad_fork_cleanup_count
;
939 if (p
->binfmt
&& !try_module_get(p
->binfmt
->module
))
940 goto bad_fork_cleanup_put_domain
;
943 delayacct_tsk_init(p
); /* Must remain after dup_task_struct() */
944 copy_flags(clone_flags
, p
);
945 INIT_LIST_HEAD(&p
->children
);
946 INIT_LIST_HEAD(&p
->sibling
);
947 #ifdef CONFIG_PREEMPT_RCU
948 p
->rcu_read_lock_nesting
= 0;
949 p
->rcu_flipctr_idx
= 0;
950 #endif /* #ifdef CONFIG_PREEMPT_RCU */
951 p
->vfork_done
= NULL
;
952 spin_lock_init(&p
->alloc_lock
);
954 clear_tsk_thread_flag(p
, TIF_SIGPENDING
);
955 init_sigpending(&p
->pending
);
957 p
->utime
= cputime_zero
;
958 p
->stime
= cputime_zero
;
959 p
->gtime
= cputime_zero
;
960 p
->utimescaled
= cputime_zero
;
961 p
->stimescaled
= cputime_zero
;
962 p
->prev_utime
= cputime_zero
;
963 p
->prev_stime
= cputime_zero
;
965 #ifdef CONFIG_DETECT_SOFTLOCKUP
966 p
->last_switch_count
= 0;
967 p
->last_switch_timestamp
= 0;
970 #ifdef CONFIG_TASK_XACCT
971 p
->rchar
= 0; /* I/O counter: bytes read */
972 p
->wchar
= 0; /* I/O counter: bytes written */
973 p
->syscr
= 0; /* I/O counter: read syscalls */
974 p
->syscw
= 0; /* I/O counter: write syscalls */
976 task_io_accounting_init(p
);
977 acct_clear_integrals(p
);
979 p
->it_virt_expires
= cputime_zero
;
980 p
->it_prof_expires
= cputime_zero
;
981 p
->it_sched_expires
= 0;
982 INIT_LIST_HEAD(&p
->cpu_timers
[0]);
983 INIT_LIST_HEAD(&p
->cpu_timers
[1]);
984 INIT_LIST_HEAD(&p
->cpu_timers
[2]);
986 p
->lock_depth
= -1; /* -1 = no lock */
987 do_posix_clock_monotonic_gettime(&p
->start_time
);
988 p
->real_start_time
= p
->start_time
;
989 monotonic_to_bootbased(&p
->real_start_time
);
990 #ifdef CONFIG_SECURITY
993 p
->cap_bset
= current
->cap_bset
;
994 p
->io_context
= NULL
;
995 p
->audit_context
= NULL
;
998 p
->mempolicy
= mpol_dup(p
->mempolicy
);
999 if (IS_ERR(p
->mempolicy
)) {
1000 retval
= PTR_ERR(p
->mempolicy
);
1001 p
->mempolicy
= NULL
;
1002 goto bad_fork_cleanup_cgroup
;
1004 mpol_fix_fork_child_flag(p
);
1006 #ifdef CONFIG_TRACE_IRQFLAGS
1008 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1009 p
->hardirqs_enabled
= 1;
1011 p
->hardirqs_enabled
= 0;
1013 p
->hardirq_enable_ip
= 0;
1014 p
->hardirq_enable_event
= 0;
1015 p
->hardirq_disable_ip
= _THIS_IP_
;
1016 p
->hardirq_disable_event
= 0;
1017 p
->softirqs_enabled
= 1;
1018 p
->softirq_enable_ip
= _THIS_IP_
;
1019 p
->softirq_enable_event
= 0;
1020 p
->softirq_disable_ip
= 0;
1021 p
->softirq_disable_event
= 0;
1022 p
->hardirq_context
= 0;
1023 p
->softirq_context
= 0;
1025 #ifdef CONFIG_LOCKDEP
1026 p
->lockdep_depth
= 0; /* no locks held yet */
1027 p
->curr_chain_key
= 0;
1028 p
->lockdep_recursion
= 0;
1031 #ifdef CONFIG_DEBUG_MUTEXES
1032 p
->blocked_on
= NULL
; /* not blocked yet */
1035 /* Perform scheduler related setup. Assign this task to a CPU. */
1036 sched_fork(p
, clone_flags
);
1038 if ((retval
= security_task_alloc(p
)))
1039 goto bad_fork_cleanup_policy
;
1040 if ((retval
= audit_alloc(p
)))
1041 goto bad_fork_cleanup_security
;
1042 /* copy all the process information */
1043 if ((retval
= copy_semundo(clone_flags
, p
)))
1044 goto bad_fork_cleanup_audit
;
1045 if ((retval
= copy_files(clone_flags
, p
)))
1046 goto bad_fork_cleanup_semundo
;
1047 if ((retval
= copy_fs(clone_flags
, p
)))
1048 goto bad_fork_cleanup_files
;
1049 if ((retval
= copy_sighand(clone_flags
, p
)))
1050 goto bad_fork_cleanup_fs
;
1051 if ((retval
= copy_signal(clone_flags
, p
)))
1052 goto bad_fork_cleanup_sighand
;
1053 if ((retval
= copy_mm(clone_flags
, p
)))
1054 goto bad_fork_cleanup_signal
;
1055 if ((retval
= copy_keys(clone_flags
, p
)))
1056 goto bad_fork_cleanup_mm
;
1057 if ((retval
= copy_namespaces(clone_flags
, p
)))
1058 goto bad_fork_cleanup_keys
;
1059 if ((retval
= copy_io(clone_flags
, p
)))
1060 goto bad_fork_cleanup_namespaces
;
1061 retval
= copy_thread(0, clone_flags
, stack_start
, stack_size
, p
, regs
);
1063 goto bad_fork_cleanup_io
;
1065 if (pid
!= &init_struct_pid
) {
1067 pid
= alloc_pid(task_active_pid_ns(p
));
1069 goto bad_fork_cleanup_io
;
1071 if (clone_flags
& CLONE_NEWPID
) {
1072 retval
= pid_ns_prepare_proc(task_active_pid_ns(p
));
1074 goto bad_fork_free_pid
;
1078 p
->pid
= pid_nr(pid
);
1080 if (clone_flags
& CLONE_THREAD
)
1081 p
->tgid
= current
->tgid
;
1083 p
->set_child_tid
= (clone_flags
& CLONE_CHILD_SETTID
) ? child_tidptr
: NULL
;
1085 * Clear TID on mm_release()?
1087 p
->clear_child_tid
= (clone_flags
& CLONE_CHILD_CLEARTID
) ? child_tidptr
: NULL
;
1089 p
->robust_list
= NULL
;
1090 #ifdef CONFIG_COMPAT
1091 p
->compat_robust_list
= NULL
;
1093 INIT_LIST_HEAD(&p
->pi_state_list
);
1094 p
->pi_state_cache
= NULL
;
1097 * sigaltstack should be cleared when sharing the same VM
1099 if ((clone_flags
& (CLONE_VM
|CLONE_VFORK
)) == CLONE_VM
)
1100 p
->sas_ss_sp
= p
->sas_ss_size
= 0;
1103 * Syscall tracing should be turned off in the child regardless
1106 clear_tsk_thread_flag(p
, TIF_SYSCALL_TRACE
);
1107 #ifdef TIF_SYSCALL_EMU
1108 clear_tsk_thread_flag(p
, TIF_SYSCALL_EMU
);
1110 clear_all_latency_tracing(p
);
1112 /* Our parent execution domain becomes current domain
1113 These must match for thread signalling to apply */
1114 p
->parent_exec_id
= p
->self_exec_id
;
1116 /* ok, now we should be set up.. */
1117 p
->exit_signal
= (clone_flags
& CLONE_THREAD
) ? -1 : (clone_flags
& CSIGNAL
);
1118 p
->pdeath_signal
= 0;
1122 * Ok, make it visible to the rest of the system.
1123 * We dont wake it up yet.
1125 p
->group_leader
= p
;
1126 INIT_LIST_HEAD(&p
->thread_group
);
1127 INIT_LIST_HEAD(&p
->ptrace_children
);
1128 INIT_LIST_HEAD(&p
->ptrace_list
);
1130 /* Now that the task is set up, run cgroup callbacks if
1131 * necessary. We need to run them before the task is visible
1132 * on the tasklist. */
1133 cgroup_fork_callbacks(p
);
1134 cgroup_callbacks_done
= 1;
1136 /* Need tasklist lock for parent etc handling! */
1137 write_lock_irq(&tasklist_lock
);
1140 * The task hasn't been attached yet, so its cpus_allowed mask will
1141 * not be changed, nor will its assigned CPU.
1143 * The cpus_allowed mask of the parent may have changed after it was
1144 * copied first time - so re-copy it here, then check the child's CPU
1145 * to ensure it is on a valid CPU (and if not, just force it back to
1146 * parent's CPU). This avoids alot of nasty races.
1148 p
->cpus_allowed
= current
->cpus_allowed
;
1149 p
->rt
.nr_cpus_allowed
= current
->rt
.nr_cpus_allowed
;
1150 if (unlikely(!cpu_isset(task_cpu(p
), p
->cpus_allowed
) ||
1151 !cpu_online(task_cpu(p
))))
1152 set_task_cpu(p
, smp_processor_id());
1154 /* CLONE_PARENT re-uses the old parent */
1155 if (clone_flags
& (CLONE_PARENT
|CLONE_THREAD
))
1156 p
->real_parent
= current
->real_parent
;
1158 p
->real_parent
= current
;
1159 p
->parent
= p
->real_parent
;
1161 spin_lock(¤t
->sighand
->siglock
);
1164 * Process group and session signals need to be delivered to just the
1165 * parent before the fork or both the parent and the child after the
1166 * fork. Restart if a signal comes in before we add the new process to
1167 * it's process group.
1168 * A fatal signal pending means that current will exit, so the new
1169 * thread can't slip out of an OOM kill (or normal SIGKILL).
1171 recalc_sigpending();
1172 if (signal_pending(current
)) {
1173 spin_unlock(¤t
->sighand
->siglock
);
1174 write_unlock_irq(&tasklist_lock
);
1175 retval
= -ERESTARTNOINTR
;
1176 goto bad_fork_free_pid
;
1179 if (clone_flags
& CLONE_THREAD
) {
1180 p
->group_leader
= current
->group_leader
;
1181 list_add_tail_rcu(&p
->thread_group
, &p
->group_leader
->thread_group
);
1183 if (!cputime_eq(current
->signal
->it_virt_expires
,
1185 !cputime_eq(current
->signal
->it_prof_expires
,
1187 current
->signal
->rlim
[RLIMIT_CPU
].rlim_cur
!= RLIM_INFINITY
||
1188 !list_empty(¤t
->signal
->cpu_timers
[0]) ||
1189 !list_empty(¤t
->signal
->cpu_timers
[1]) ||
1190 !list_empty(¤t
->signal
->cpu_timers
[2])) {
1192 * Have child wake up on its first tick to check
1193 * for process CPU timers.
1195 p
->it_prof_expires
= jiffies_to_cputime(1);
1199 if (likely(p
->pid
)) {
1201 if (unlikely(p
->ptrace
& PT_PTRACED
))
1202 __ptrace_link(p
, current
->parent
);
1204 if (thread_group_leader(p
)) {
1205 if (clone_flags
& CLONE_NEWPID
)
1206 p
->nsproxy
->pid_ns
->child_reaper
= p
;
1208 p
->signal
->leader_pid
= pid
;
1209 p
->signal
->tty
= current
->signal
->tty
;
1210 set_task_pgrp(p
, task_pgrp_nr(current
));
1211 set_task_session(p
, task_session_nr(current
));
1212 attach_pid(p
, PIDTYPE_PGID
, task_pgrp(current
));
1213 attach_pid(p
, PIDTYPE_SID
, task_session(current
));
1214 list_add_tail_rcu(&p
->tasks
, &init_task
.tasks
);
1215 __get_cpu_var(process_counts
)++;
1217 attach_pid(p
, PIDTYPE_PID
, pid
);
1222 spin_unlock(¤t
->sighand
->siglock
);
1223 write_unlock_irq(&tasklist_lock
);
1224 proc_fork_connector(p
);
1225 cgroup_post_fork(p
);
1229 if (pid
!= &init_struct_pid
)
1231 bad_fork_cleanup_io
:
1232 put_io_context(p
->io_context
);
1233 bad_fork_cleanup_namespaces
:
1234 exit_task_namespaces(p
);
1235 bad_fork_cleanup_keys
:
1237 bad_fork_cleanup_mm
:
1240 bad_fork_cleanup_signal
:
1242 bad_fork_cleanup_sighand
:
1243 __cleanup_sighand(p
->sighand
);
1244 bad_fork_cleanup_fs
:
1245 exit_fs(p
); /* blocking */
1246 bad_fork_cleanup_files
:
1247 exit_files(p
); /* blocking */
1248 bad_fork_cleanup_semundo
:
1250 bad_fork_cleanup_audit
:
1252 bad_fork_cleanup_security
:
1253 security_task_free(p
);
1254 bad_fork_cleanup_policy
:
1256 mpol_put(p
->mempolicy
);
1257 bad_fork_cleanup_cgroup
:
1259 cgroup_exit(p
, cgroup_callbacks_done
);
1260 delayacct_tsk_free(p
);
1262 module_put(p
->binfmt
->module
);
1263 bad_fork_cleanup_put_domain
:
1264 module_put(task_thread_info(p
)->exec_domain
->module
);
1265 bad_fork_cleanup_count
:
1266 put_group_info(p
->group_info
);
1267 atomic_dec(&p
->user
->processes
);
1272 return ERR_PTR(retval
);
1275 noinline
struct pt_regs
* __cpuinit
__attribute__((weak
)) idle_regs(struct pt_regs
*regs
)
1277 memset(regs
, 0, sizeof(struct pt_regs
));
1281 struct task_struct
* __cpuinit
fork_idle(int cpu
)
1283 struct task_struct
*task
;
1284 struct pt_regs regs
;
1286 task
= copy_process(CLONE_VM
, 0, idle_regs(®s
), 0, NULL
,
1289 init_idle(task
, cpu
);
1294 static int fork_traceflag(unsigned clone_flags
)
1296 if (clone_flags
& CLONE_UNTRACED
)
1298 else if (clone_flags
& CLONE_VFORK
) {
1299 if (current
->ptrace
& PT_TRACE_VFORK
)
1300 return PTRACE_EVENT_VFORK
;
1301 } else if ((clone_flags
& CSIGNAL
) != SIGCHLD
) {
1302 if (current
->ptrace
& PT_TRACE_CLONE
)
1303 return PTRACE_EVENT_CLONE
;
1304 } else if (current
->ptrace
& PT_TRACE_FORK
)
1305 return PTRACE_EVENT_FORK
;
1311 * Ok, this is the main fork-routine.
1313 * It copies the process, and if successful kick-starts
1314 * it and waits for it to finish using the VM if required.
1316 long do_fork(unsigned long clone_flags
,
1317 unsigned long stack_start
,
1318 struct pt_regs
*regs
,
1319 unsigned long stack_size
,
1320 int __user
*parent_tidptr
,
1321 int __user
*child_tidptr
)
1323 struct task_struct
*p
;
1328 * We hope to recycle these flags after 2.6.26
1330 if (unlikely(clone_flags
& CLONE_STOPPED
)) {
1331 static int __read_mostly count
= 100;
1333 if (count
> 0 && printk_ratelimit()) {
1334 char comm
[TASK_COMM_LEN
];
1337 printk(KERN_INFO
"fork(): process `%s' used deprecated "
1338 "clone flags 0x%lx\n",
1339 get_task_comm(comm
, current
),
1340 clone_flags
& CLONE_STOPPED
);
1344 if (unlikely(current
->ptrace
)) {
1345 trace
= fork_traceflag (clone_flags
);
1347 clone_flags
|= CLONE_PTRACE
;
1350 p
= copy_process(clone_flags
, stack_start
, regs
, stack_size
,
1351 child_tidptr
, NULL
);
1353 * Do this prior waking up the new thread - the thread pointer
1354 * might get invalid after that point, if the thread exits quickly.
1357 struct completion vfork
;
1359 nr
= task_pid_vnr(p
);
1361 if (clone_flags
& CLONE_PARENT_SETTID
)
1362 put_user(nr
, parent_tidptr
);
1364 if (clone_flags
& CLONE_VFORK
) {
1365 p
->vfork_done
= &vfork
;
1366 init_completion(&vfork
);
1369 if ((p
->ptrace
& PT_PTRACED
) || (clone_flags
& CLONE_STOPPED
)) {
1371 * We'll start up with an immediate SIGSTOP.
1373 sigaddset(&p
->pending
.signal
, SIGSTOP
);
1374 set_tsk_thread_flag(p
, TIF_SIGPENDING
);
1377 if (!(clone_flags
& CLONE_STOPPED
))
1378 wake_up_new_task(p
, clone_flags
);
1380 __set_task_state(p
, TASK_STOPPED
);
1382 if (unlikely (trace
)) {
1383 current
->ptrace_message
= nr
;
1384 ptrace_notify ((trace
<< 8) | SIGTRAP
);
1387 if (clone_flags
& CLONE_VFORK
) {
1388 freezer_do_not_count();
1389 wait_for_completion(&vfork
);
1391 if (unlikely (current
->ptrace
& PT_TRACE_VFORK_DONE
)) {
1392 current
->ptrace_message
= nr
;
1393 ptrace_notify ((PTRACE_EVENT_VFORK_DONE
<< 8) | SIGTRAP
);
1402 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
1403 #define ARCH_MIN_MMSTRUCT_ALIGN 0
1406 static void sighand_ctor(struct kmem_cache
*cachep
, void *data
)
1408 struct sighand_struct
*sighand
= data
;
1410 spin_lock_init(&sighand
->siglock
);
1411 init_waitqueue_head(&sighand
->signalfd_wqh
);
1414 void __init
proc_caches_init(void)
1416 sighand_cachep
= kmem_cache_create("sighand_cache",
1417 sizeof(struct sighand_struct
), 0,
1418 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_DESTROY_BY_RCU
,
1420 signal_cachep
= kmem_cache_create("signal_cache",
1421 sizeof(struct signal_struct
), 0,
1422 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1423 files_cachep
= kmem_cache_create("files_cache",
1424 sizeof(struct files_struct
), 0,
1425 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1426 fs_cachep
= kmem_cache_create("fs_cache",
1427 sizeof(struct fs_struct
), 0,
1428 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1429 vm_area_cachep
= kmem_cache_create("vm_area_struct",
1430 sizeof(struct vm_area_struct
), 0,
1432 mm_cachep
= kmem_cache_create("mm_struct",
1433 sizeof(struct mm_struct
), ARCH_MIN_MMSTRUCT_ALIGN
,
1434 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1438 * Check constraints on flags passed to the unshare system call and
1439 * force unsharing of additional process context as appropriate.
1441 static void check_unshare_flags(unsigned long *flags_ptr
)
1444 * If unsharing a thread from a thread group, must also
1447 if (*flags_ptr
& CLONE_THREAD
)
1448 *flags_ptr
|= CLONE_VM
;
1451 * If unsharing vm, must also unshare signal handlers.
1453 if (*flags_ptr
& CLONE_VM
)
1454 *flags_ptr
|= CLONE_SIGHAND
;
1457 * If unsharing signal handlers and the task was created
1458 * using CLONE_THREAD, then must unshare the thread
1460 if ((*flags_ptr
& CLONE_SIGHAND
) &&
1461 (atomic_read(¤t
->signal
->count
) > 1))
1462 *flags_ptr
|= CLONE_THREAD
;
1465 * If unsharing namespace, must also unshare filesystem information.
1467 if (*flags_ptr
& CLONE_NEWNS
)
1468 *flags_ptr
|= CLONE_FS
;
1472 * Unsharing of tasks created with CLONE_THREAD is not supported yet
1474 static int unshare_thread(unsigned long unshare_flags
)
1476 if (unshare_flags
& CLONE_THREAD
)
1483 * Unshare the filesystem structure if it is being shared
1485 static int unshare_fs(unsigned long unshare_flags
, struct fs_struct
**new_fsp
)
1487 struct fs_struct
*fs
= current
->fs
;
1489 if ((unshare_flags
& CLONE_FS
) &&
1490 (fs
&& atomic_read(&fs
->count
) > 1)) {
1491 *new_fsp
= __copy_fs_struct(current
->fs
);
1500 * Unsharing of sighand is not supported yet
1502 static int unshare_sighand(unsigned long unshare_flags
, struct sighand_struct
**new_sighp
)
1504 struct sighand_struct
*sigh
= current
->sighand
;
1506 if ((unshare_flags
& CLONE_SIGHAND
) && atomic_read(&sigh
->count
) > 1)
1513 * Unshare vm if it is being shared
1515 static int unshare_vm(unsigned long unshare_flags
, struct mm_struct
**new_mmp
)
1517 struct mm_struct
*mm
= current
->mm
;
1519 if ((unshare_flags
& CLONE_VM
) &&
1520 (mm
&& atomic_read(&mm
->mm_users
) > 1)) {
1528 * Unshare file descriptor table if it is being shared
1530 static int unshare_fd(unsigned long unshare_flags
, struct files_struct
**new_fdp
)
1532 struct files_struct
*fd
= current
->files
;
1535 if ((unshare_flags
& CLONE_FILES
) &&
1536 (fd
&& atomic_read(&fd
->count
) > 1)) {
1537 *new_fdp
= dup_fd(fd
, &error
);
1546 * unshare allows a process to 'unshare' part of the process
1547 * context which was originally shared using clone. copy_*
1548 * functions used by do_fork() cannot be used here directly
1549 * because they modify an inactive task_struct that is being
1550 * constructed. Here we are modifying the current, active,
1553 asmlinkage
long sys_unshare(unsigned long unshare_flags
)
1556 struct fs_struct
*fs
, *new_fs
= NULL
;
1557 struct sighand_struct
*new_sigh
= NULL
;
1558 struct mm_struct
*mm
, *new_mm
= NULL
, *active_mm
= NULL
;
1559 struct files_struct
*fd
, *new_fd
= NULL
;
1560 struct nsproxy
*new_nsproxy
= NULL
;
1563 check_unshare_flags(&unshare_flags
);
1565 /* Return -EINVAL for all unsupported flags */
1567 if (unshare_flags
& ~(CLONE_THREAD
|CLONE_FS
|CLONE_NEWNS
|CLONE_SIGHAND
|
1568 CLONE_VM
|CLONE_FILES
|CLONE_SYSVSEM
|
1569 CLONE_NEWUTS
|CLONE_NEWIPC
|CLONE_NEWUSER
|
1571 goto bad_unshare_out
;
1574 * CLONE_NEWIPC must also detach from the undolist: after switching
1575 * to a new ipc namespace, the semaphore arrays from the old
1576 * namespace are unreachable.
1578 if (unshare_flags
& (CLONE_NEWIPC
|CLONE_SYSVSEM
))
1580 if ((err
= unshare_thread(unshare_flags
)))
1581 goto bad_unshare_out
;
1582 if ((err
= unshare_fs(unshare_flags
, &new_fs
)))
1583 goto bad_unshare_cleanup_thread
;
1584 if ((err
= unshare_sighand(unshare_flags
, &new_sigh
)))
1585 goto bad_unshare_cleanup_fs
;
1586 if ((err
= unshare_vm(unshare_flags
, &new_mm
)))
1587 goto bad_unshare_cleanup_sigh
;
1588 if ((err
= unshare_fd(unshare_flags
, &new_fd
)))
1589 goto bad_unshare_cleanup_vm
;
1590 if ((err
= unshare_nsproxy_namespaces(unshare_flags
, &new_nsproxy
,
1592 goto bad_unshare_cleanup_fd
;
1594 if (new_fs
|| new_mm
|| new_fd
|| do_sysvsem
|| new_nsproxy
) {
1597 * CLONE_SYSVSEM is equivalent to sys_exit().
1603 switch_task_namespaces(current
, new_nsproxy
);
1611 current
->fs
= new_fs
;
1617 active_mm
= current
->active_mm
;
1618 current
->mm
= new_mm
;
1619 current
->active_mm
= new_mm
;
1620 activate_mm(active_mm
, new_mm
);
1625 fd
= current
->files
;
1626 current
->files
= new_fd
;
1630 task_unlock(current
);
1634 put_nsproxy(new_nsproxy
);
1636 bad_unshare_cleanup_fd
:
1638 put_files_struct(new_fd
);
1640 bad_unshare_cleanup_vm
:
1644 bad_unshare_cleanup_sigh
:
1646 if (atomic_dec_and_test(&new_sigh
->count
))
1647 kmem_cache_free(sighand_cachep
, new_sigh
);
1649 bad_unshare_cleanup_fs
:
1651 put_fs_struct(new_fs
);
1653 bad_unshare_cleanup_thread
:
1659 * Helper to unshare the files of the current task.
1660 * We don't want to expose copy_files internals to
1661 * the exec layer of the kernel.
1664 int unshare_files(struct files_struct
**displaced
)
1666 struct task_struct
*task
= current
;
1667 struct files_struct
*copy
= NULL
;
1670 error
= unshare_fd(CLONE_FILES
, ©
);
1671 if (error
|| !copy
) {
1675 *displaced
= task
->files
;