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/key.h>
26 #include <linux/binfmts.h>
27 #include <linux/mman.h>
29 #include <linux/nsproxy.h>
30 #include <linux/capability.h>
31 #include <linux/cpu.h>
32 #include <linux/cgroup.h>
33 #include <linux/security.h>
34 #include <linux/swap.h>
35 #include <linux/syscalls.h>
36 #include <linux/jiffies.h>
37 #include <linux/futex.h>
38 #include <linux/task_io_accounting_ops.h>
39 #include <linux/rcupdate.h>
40 #include <linux/ptrace.h>
41 #include <linux/mount.h>
42 #include <linux/audit.h>
43 #include <linux/memcontrol.h>
44 #include <linux/profile.h>
45 #include <linux/rmap.h>
46 #include <linux/acct.h>
47 #include <linux/tsacct_kern.h>
48 #include <linux/cn_proc.h>
49 #include <linux/freezer.h>
50 #include <linux/delayacct.h>
51 #include <linux/taskstats_kern.h>
52 #include <linux/random.h>
53 #include <linux/tty.h>
54 #include <linux/proc_fs.h>
55 #include <linux/blkdev.h>
57 #include <asm/pgtable.h>
58 #include <asm/pgalloc.h>
59 #include <asm/uaccess.h>
60 #include <asm/mmu_context.h>
61 #include <asm/cacheflush.h>
62 #include <asm/tlbflush.h>
65 * Protected counters by write_lock_irq(&tasklist_lock)
67 unsigned long total_forks; /* Handle normal Linux uptimes. */
68 int nr_threads; /* The idle threads do not count.. */
70 int max_threads; /* tunable limit on nr_threads */
72 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
74 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
76 int nr_processes(void)
81 for_each_online_cpu(cpu)
82 total += per_cpu(process_counts, cpu);
87 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
88 # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
89 # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk))
90 static struct kmem_cache *task_struct_cachep;
93 /* SLAB cache for signal_struct structures (tsk->signal) */
94 static struct kmem_cache *signal_cachep;
96 /* SLAB cache for sighand_struct structures (tsk->sighand) */
97 struct kmem_cache *sighand_cachep;
99 /* SLAB cache for files_struct structures (tsk->files) */
100 struct kmem_cache *files_cachep;
102 /* SLAB cache for fs_struct structures (tsk->fs) */
103 struct kmem_cache *fs_cachep;
105 /* SLAB cache for vm_area_struct structures */
106 struct kmem_cache *vm_area_cachep;
108 /* SLAB cache for mm_struct structures (tsk->mm) */
109 static struct kmem_cache *mm_cachep;
111 void free_task(struct task_struct *tsk)
113 prop_local_destroy_single(&tsk->dirties);
114 free_thread_info(tsk->stack);
115 rt_mutex_debug_task_free(tsk);
116 free_task_struct(tsk);
118 EXPORT_SYMBOL(free_task);
120 void __put_task_struct(struct task_struct *tsk)
122 WARN_ON(!tsk->exit_state);
123 WARN_ON(atomic_read(&tsk->usage));
124 WARN_ON(tsk == current);
126 security_task_free(tsk);
128 put_group_info(tsk->group_info);
129 delayacct_tsk_free(tsk);
131 if (!profile_handoff_task(tsk))
136 * macro override instead of weak attribute alias, to workaround
137 * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
139 #ifndef arch_task_cache_init
140 #define arch_task_cache_init()
143 void __init fork_init(unsigned long mempages)
145 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
146 #ifndef ARCH_MIN_TASKALIGN
147 #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
149 /* create a slab on which task_structs can be allocated */
151 kmem_cache_create("task_struct", sizeof(struct task_struct),
152 ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL);
155 /* do the arch specific task caches init */
156 arch_task_cache_init();
159 * The default maximum number of threads is set to a safe
160 * value: the thread structures can take up at most half
163 max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
166 * we need to allow at least 20 threads to boot a system
171 init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
172 init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
173 init_task.signal->rlim[RLIMIT_SIGPENDING] =
174 init_task.signal->rlim[RLIMIT_NPROC];
177 int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst,
178 struct task_struct *src)
184 static struct task_struct *dup_task_struct(struct task_struct *orig)
186 struct task_struct *tsk;
187 struct thread_info *ti;
190 prepare_to_copy(orig);
192 tsk = alloc_task_struct();
196 ti = alloc_thread_info(tsk);
198 free_task_struct(tsk);
202 err = arch_dup_task_struct(tsk, orig);
208 err = prop_local_init_single(&tsk->dirties);
212 setup_thread_stack(tsk, orig);
214 #ifdef CONFIG_CC_STACKPROTECTOR
215 tsk->stack_canary = get_random_int();
218 /* One for us, one for whoever does the "release_task()" (usually parent) */
219 atomic_set(&tsk->usage,2);
220 atomic_set(&tsk->fs_excl, 0);
221 #ifdef CONFIG_BLK_DEV_IO_TRACE
224 tsk->splice_pipe = NULL;
228 free_thread_info(ti);
229 free_task_struct(tsk);
234 static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
236 struct vm_area_struct *mpnt, *tmp, **pprev;
237 struct rb_node **rb_link, *rb_parent;
239 unsigned long charge;
240 struct mempolicy *pol;
242 down_write(&oldmm->mmap_sem);
243 flush_cache_dup_mm(oldmm);
245 * Not linked in yet - no deadlock potential:
247 down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
251 mm->mmap_cache = NULL;
252 mm->free_area_cache = oldmm->mmap_base;
253 mm->cached_hole_size = ~0UL;
255 cpus_clear(mm->cpu_vm_mask);
257 rb_link = &mm->mm_rb.rb_node;
261 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
264 if (mpnt->vm_flags & VM_DONTCOPY) {
265 long pages = vma_pages(mpnt);
266 mm->total_vm -= pages;
267 vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
272 if (mpnt->vm_flags & VM_ACCOUNT) {
273 unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
274 if (security_vm_enough_memory(len))
278 tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
282 pol = mpol_copy(vma_policy(mpnt));
283 retval = PTR_ERR(pol);
285 goto fail_nomem_policy;
286 vma_set_policy(tmp, pol);
287 tmp->vm_flags &= ~VM_LOCKED;
293 struct inode *inode = file->f_path.dentry->d_inode;
295 if (tmp->vm_flags & VM_DENYWRITE)
296 atomic_dec(&inode->i_writecount);
298 /* insert tmp into the share list, just after mpnt */
299 spin_lock(&file->f_mapping->i_mmap_lock);
300 tmp->vm_truncate_count = mpnt->vm_truncate_count;
301 flush_dcache_mmap_lock(file->f_mapping);
302 vma_prio_tree_add(tmp, mpnt);
303 flush_dcache_mmap_unlock(file->f_mapping);
304 spin_unlock(&file->f_mapping->i_mmap_lock);
308 * Link in the new vma and copy the page table entries.
311 pprev = &tmp->vm_next;
313 __vma_link_rb(mm, tmp, rb_link, rb_parent);
314 rb_link = &tmp->vm_rb.rb_right;
315 rb_parent = &tmp->vm_rb;
318 retval = copy_page_range(mm, oldmm, mpnt);
320 if (tmp->vm_ops && tmp->vm_ops->open)
321 tmp->vm_ops->open(tmp);
326 /* a new mm has just been created */
327 arch_dup_mmap(oldmm, mm);
330 up_write(&mm->mmap_sem);
332 up_write(&oldmm->mmap_sem);
335 kmem_cache_free(vm_area_cachep, tmp);
338 vm_unacct_memory(charge);
342 static inline int mm_alloc_pgd(struct mm_struct * mm)
344 mm->pgd = pgd_alloc(mm);
345 if (unlikely(!mm->pgd))
350 static inline void mm_free_pgd(struct mm_struct * mm)
352 pgd_free(mm, mm->pgd);
355 #define dup_mmap(mm, oldmm) (0)
356 #define mm_alloc_pgd(mm) (0)
357 #define mm_free_pgd(mm)
358 #endif /* CONFIG_MMU */
360 __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
362 #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
363 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
365 #include <linux/init_task.h>
367 static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
369 atomic_set(&mm->mm_users, 1);
370 atomic_set(&mm->mm_count, 1);
371 init_rwsem(&mm->mmap_sem);
372 INIT_LIST_HEAD(&mm->mmlist);
373 mm->flags = (current->mm) ? current->mm->flags
374 : MMF_DUMP_FILTER_DEFAULT;
375 mm->core_waiters = 0;
377 set_mm_counter(mm, file_rss, 0);
378 set_mm_counter(mm, anon_rss, 0);
379 spin_lock_init(&mm->page_table_lock);
380 rwlock_init(&mm->ioctx_list_lock);
381 mm->ioctx_list = NULL;
382 mm->free_area_cache = TASK_UNMAPPED_BASE;
383 mm->cached_hole_size = ~0UL;
384 mm_init_cgroup(mm, p);
386 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 if (!list_empty(&mm->mmlist)) {
436 spin_lock(&mmlist_lock);
437 list_del(&mm->mmlist);
438 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 static 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 err = dup_mmap(mm, oldmm);
552 mm->hiwater_rss = get_mm_rss(mm);
553 mm->hiwater_vm = mm->total_vm;
565 * If init_new_context() failed, we cannot use mmput() to free the mm
566 * because it calls destroy_context()
573 static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
575 struct mm_struct * mm, *oldmm;
578 tsk->min_flt = tsk->maj_flt = 0;
579 tsk->nvcsw = tsk->nivcsw = 0;
582 tsk->active_mm = NULL;
585 * Are we cloning a kernel thread?
587 * We need to steal a active VM for that..
593 if (clone_flags & CLONE_VM) {
594 atomic_inc(&oldmm->mm_users);
605 /* Initializing for Swap token stuff */
606 mm->token_priority = 0;
607 mm->last_interval = 0;
617 static struct fs_struct *__copy_fs_struct(struct fs_struct *old)
619 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
620 /* We don't need to lock fs - think why ;-) */
622 atomic_set(&fs->count, 1);
623 rwlock_init(&fs->lock);
624 fs->umask = old->umask;
625 read_lock(&old->lock);
626 fs->root = old->root;
627 path_get(&old->root);
630 if (old->altroot.dentry) {
631 fs->altroot = old->altroot;
632 path_get(&old->altroot);
634 fs->altroot.mnt = NULL;
635 fs->altroot.dentry = NULL;
637 read_unlock(&old->lock);
642 struct fs_struct *copy_fs_struct(struct fs_struct *old)
644 return __copy_fs_struct(old);
647 EXPORT_SYMBOL_GPL(copy_fs_struct);
649 static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
651 if (clone_flags & CLONE_FS) {
652 atomic_inc(¤t->fs->count);
655 tsk->fs = __copy_fs_struct(current->fs);
661 static int count_open_files(struct fdtable *fdt)
663 int size = fdt->max_fds;
666 /* Find the last open fd */
667 for (i = size/(8*sizeof(long)); i > 0; ) {
668 if (fdt->open_fds->fds_bits[--i])
671 i = (i+1) * 8 * sizeof(long);
675 static struct files_struct *alloc_files(void)
677 struct files_struct *newf;
680 newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
684 atomic_set(&newf->count, 1);
686 spin_lock_init(&newf->file_lock);
689 fdt->max_fds = NR_OPEN_DEFAULT;
690 fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init;
691 fdt->open_fds = (fd_set *)&newf->open_fds_init;
692 fdt->fd = &newf->fd_array[0];
693 INIT_RCU_HEAD(&fdt->rcu);
695 rcu_assign_pointer(newf->fdt, fdt);
701 * Allocate a new files structure and copy contents from the
702 * passed in files structure.
703 * errorp will be valid only when the returned files_struct is NULL.
705 static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
707 struct files_struct *newf;
708 struct file **old_fds, **new_fds;
709 int open_files, size, i;
710 struct fdtable *old_fdt, *new_fdt;
713 newf = alloc_files();
717 spin_lock(&oldf->file_lock);
718 old_fdt = files_fdtable(oldf);
719 new_fdt = files_fdtable(newf);
720 open_files = count_open_files(old_fdt);
723 * Check whether we need to allocate a larger fd array and fd set.
724 * Note: we're not a clone task, so the open count won't change.
726 if (open_files > new_fdt->max_fds) {
727 new_fdt->max_fds = 0;
728 spin_unlock(&oldf->file_lock);
729 spin_lock(&newf->file_lock);
730 *errorp = expand_files(newf, open_files-1);
731 spin_unlock(&newf->file_lock);
734 new_fdt = files_fdtable(newf);
736 * Reacquire the oldf lock and a pointer to its fd table
737 * who knows it may have a new bigger fd table. We need
738 * the latest pointer.
740 spin_lock(&oldf->file_lock);
741 old_fdt = files_fdtable(oldf);
744 old_fds = old_fdt->fd;
745 new_fds = new_fdt->fd;
747 memcpy(new_fdt->open_fds->fds_bits,
748 old_fdt->open_fds->fds_bits, open_files/8);
749 memcpy(new_fdt->close_on_exec->fds_bits,
750 old_fdt->close_on_exec->fds_bits, open_files/8);
752 for (i = open_files; i != 0; i--) {
753 struct file *f = *old_fds++;
758 * The fd may be claimed in the fd bitmap but not yet
759 * instantiated in the files array if a sibling thread
760 * is partway through open(). So make sure that this
761 * fd is available to the new process.
763 FD_CLR(open_files - i, new_fdt->open_fds);
765 rcu_assign_pointer(*new_fds++, f);
767 spin_unlock(&oldf->file_lock);
769 /* compute the remainder to be cleared */
770 size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
772 /* This is long word aligned thus could use a optimized version */
773 memset(new_fds, 0, size);
775 if (new_fdt->max_fds > open_files) {
776 int left = (new_fdt->max_fds-open_files)/8;
777 int start = open_files / (8 * sizeof(unsigned long));
779 memset(&new_fdt->open_fds->fds_bits[start], 0, left);
780 memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
786 kmem_cache_free(files_cachep, newf);
791 static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
793 struct files_struct *oldf, *newf;
797 * A background process may not have any files ...
799 oldf = current->files;
803 if (clone_flags & CLONE_FILES) {
804 atomic_inc(&oldf->count);
808 newf = dup_fd(oldf, &error);
818 static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
821 struct io_context *ioc = current->io_context;
826 * Share io context with parent, if CLONE_IO is set
828 if (clone_flags & CLONE_IO) {
829 tsk->io_context = ioc_task_link(ioc);
830 if (unlikely(!tsk->io_context))
832 } else if (ioprio_valid(ioc->ioprio)) {
833 tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
834 if (unlikely(!tsk->io_context))
837 tsk->io_context->ioprio = ioc->ioprio;
844 * Helper to unshare the files of the current task.
845 * We don't want to expose copy_files internals to
846 * the exec layer of the kernel.
849 int unshare_files(void)
851 struct files_struct *files = current->files;
852 struct files_struct *newf;
857 /* This can race but the race causes us to copy when we don't
858 need to and drop the copy */
859 if(atomic_read(&files->count) == 1)
861 atomic_inc(&files->count);
864 newf = dup_fd(files, &error);
867 current->files = newf;
868 task_unlock(current);
873 EXPORT_SYMBOL(unshare_files);
875 static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
877 struct sighand_struct *sig;
879 if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
880 atomic_inc(¤t->sighand->count);
883 sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
884 rcu_assign_pointer(tsk->sighand, sig);
887 atomic_set(&sig->count, 1);
888 memcpy(sig->action, current->sighand->action, sizeof(sig->action));
892 void __cleanup_sighand(struct sighand_struct *sighand)
894 if (atomic_dec_and_test(&sighand->count))
895 kmem_cache_free(sighand_cachep, sighand);
898 static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
900 struct signal_struct *sig;
903 if (clone_flags & CLONE_THREAD) {
904 atomic_inc(¤t->signal->count);
905 atomic_inc(¤t->signal->live);
908 sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
913 ret = copy_thread_group_keys(tsk);
915 kmem_cache_free(signal_cachep, sig);
919 atomic_set(&sig->count, 1);
920 atomic_set(&sig->live, 1);
921 init_waitqueue_head(&sig->wait_chldexit);
923 sig->group_exit_code = 0;
924 sig->group_exit_task = NULL;
925 sig->group_stop_count = 0;
926 sig->curr_target = NULL;
927 init_sigpending(&sig->shared_pending);
928 INIT_LIST_HEAD(&sig->posix_timers);
930 hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
931 sig->it_real_incr.tv64 = 0;
932 sig->real_timer.function = it_real_fn;
934 sig->it_virt_expires = cputime_zero;
935 sig->it_virt_incr = cputime_zero;
936 sig->it_prof_expires = cputime_zero;
937 sig->it_prof_incr = cputime_zero;
939 sig->leader = 0; /* session leadership doesn't inherit */
940 sig->tty_old_pgrp = NULL;
942 sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
943 sig->gtime = cputime_zero;
944 sig->cgtime = cputime_zero;
945 sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
946 sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
947 sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0;
948 sig->sum_sched_runtime = 0;
949 INIT_LIST_HEAD(&sig->cpu_timers[0]);
950 INIT_LIST_HEAD(&sig->cpu_timers[1]);
951 INIT_LIST_HEAD(&sig->cpu_timers[2]);
952 taskstats_tgid_init(sig);
954 task_lock(current->group_leader);
955 memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
956 task_unlock(current->group_leader);
958 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
960 * New sole thread in the process gets an expiry time
961 * of the whole CPU time limit.
963 tsk->it_prof_expires =
964 secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
966 acct_init_pacct(&sig->pacct);
973 void __cleanup_signal(struct signal_struct *sig)
975 exit_thread_group_keys(sig);
976 kmem_cache_free(signal_cachep, sig);
979 static void cleanup_signal(struct task_struct *tsk)
981 struct signal_struct *sig = tsk->signal;
983 atomic_dec(&sig->live);
985 if (atomic_dec_and_test(&sig->count))
986 __cleanup_signal(sig);
989 static void copy_flags(unsigned long clone_flags, struct task_struct *p)
991 unsigned long new_flags = p->flags;
993 new_flags &= ~PF_SUPERPRIV;
994 new_flags |= PF_FORKNOEXEC;
995 if (!(clone_flags & CLONE_PTRACE))
997 p->flags = new_flags;
998 clear_freeze_flag(p);
1001 asmlinkage long sys_set_tid_address(int __user *tidptr)
1003 current->clear_child_tid = tidptr;
1005 return task_pid_vnr(current);
1008 static void rt_mutex_init_task(struct task_struct *p)
1010 spin_lock_init(&p->pi_lock);
1011 #ifdef CONFIG_RT_MUTEXES
1012 plist_head_init(&p->pi_waiters, &p->pi_lock);
1013 p->pi_blocked_on = NULL;
1018 * This creates a new process as a copy of the old one,
1019 * but does not actually start it yet.
1021 * It copies the registers, and all the appropriate
1022 * parts of the process environment (as per the clone
1023 * flags). The actual kick-off is left to the caller.
1025 static struct task_struct *copy_process(unsigned long clone_flags,
1026 unsigned long stack_start,
1027 struct pt_regs *regs,
1028 unsigned long stack_size,
1029 int __user *child_tidptr,
1033 struct task_struct *p;
1034 int cgroup_callbacks_done = 0;
1036 if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
1037 return ERR_PTR(-EINVAL);
1040 * Thread groups must share signals as well, and detached threads
1041 * can only be started up within the thread group.
1043 if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
1044 return ERR_PTR(-EINVAL);
1047 * Shared signal handlers imply shared VM. By way of the above,
1048 * thread groups also imply shared VM. Blocking this case allows
1049 * for various simplifications in other code.
1051 if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
1052 return ERR_PTR(-EINVAL);
1054 retval = security_task_create(clone_flags);
1059 p = dup_task_struct(current);
1063 rt_mutex_init_task(p);
1065 #ifdef CONFIG_TRACE_IRQFLAGS
1066 DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
1067 DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
1070 if (atomic_read(&p->user->processes) >=
1071 p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
1072 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
1073 p->user != current->nsproxy->user_ns->root_user)
1077 atomic_inc(&p->user->__count);
1078 atomic_inc(&p->user->processes);
1079 get_group_info(p->group_info);
1082 * If multiple threads are within copy_process(), then this check
1083 * triggers too late. This doesn't hurt, the check is only there
1084 * to stop root fork bombs.
1086 if (nr_threads >= max_threads)
1087 goto bad_fork_cleanup_count;
1089 if (!try_module_get(task_thread_info(p)->exec_domain->module))
1090 goto bad_fork_cleanup_count;
1092 if (p->binfmt && !try_module_get(p->binfmt->module))
1093 goto bad_fork_cleanup_put_domain;
1096 delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
1097 copy_flags(clone_flags, p);
1098 INIT_LIST_HEAD(&p->children);
1099 INIT_LIST_HEAD(&p->sibling);
1100 #ifdef CONFIG_PREEMPT_RCU
1101 p->rcu_read_lock_nesting = 0;
1102 p->rcu_flipctr_idx = 0;
1103 #endif /* #ifdef CONFIG_PREEMPT_RCU */
1104 p->vfork_done = NULL;
1105 spin_lock_init(&p->alloc_lock);
1107 clear_tsk_thread_flag(p, TIF_SIGPENDING);
1108 init_sigpending(&p->pending);
1110 p->utime = cputime_zero;
1111 p->stime = cputime_zero;
1112 p->gtime = cputime_zero;
1113 p->utimescaled = cputime_zero;
1114 p->stimescaled = cputime_zero;
1115 p->prev_utime = cputime_zero;
1116 p->prev_stime = cputime_zero;
1118 #ifdef CONFIG_DETECT_SOFTLOCKUP
1119 p->last_switch_count = 0;
1120 p->last_switch_timestamp = 0;
1123 #ifdef CONFIG_TASK_XACCT
1124 p->rchar = 0; /* I/O counter: bytes read */
1125 p->wchar = 0; /* I/O counter: bytes written */
1126 p->syscr = 0; /* I/O counter: read syscalls */
1127 p->syscw = 0; /* I/O counter: write syscalls */
1129 task_io_accounting_init(p);
1130 acct_clear_integrals(p);
1132 p->it_virt_expires = cputime_zero;
1133 p->it_prof_expires = cputime_zero;
1134 p->it_sched_expires = 0;
1135 INIT_LIST_HEAD(&p->cpu_timers[0]);
1136 INIT_LIST_HEAD(&p->cpu_timers[1]);
1137 INIT_LIST_HEAD(&p->cpu_timers[2]);
1139 p->lock_depth = -1; /* -1 = no lock */
1140 do_posix_clock_monotonic_gettime(&p->start_time);
1141 p->real_start_time = p->start_time;
1142 monotonic_to_bootbased(&p->real_start_time);
1143 #ifdef CONFIG_SECURITY
1146 p->cap_bset = current->cap_bset;
1147 p->io_context = NULL;
1148 p->audit_context = NULL;
1151 p->mempolicy = mpol_copy(p->mempolicy);
1152 if (IS_ERR(p->mempolicy)) {
1153 retval = PTR_ERR(p->mempolicy);
1154 p->mempolicy = NULL;
1155 goto bad_fork_cleanup_cgroup;
1157 mpol_fix_fork_child_flag(p);
1159 #ifdef CONFIG_TRACE_IRQFLAGS
1161 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1162 p->hardirqs_enabled = 1;
1164 p->hardirqs_enabled = 0;
1166 p->hardirq_enable_ip = 0;
1167 p->hardirq_enable_event = 0;
1168 p->hardirq_disable_ip = _THIS_IP_;
1169 p->hardirq_disable_event = 0;
1170 p->softirqs_enabled = 1;
1171 p->softirq_enable_ip = _THIS_IP_;
1172 p->softirq_enable_event = 0;
1173 p->softirq_disable_ip = 0;
1174 p->softirq_disable_event = 0;
1175 p->hardirq_context = 0;
1176 p->softirq_context = 0;
1178 #ifdef CONFIG_LOCKDEP
1179 p->lockdep_depth = 0; /* no locks held yet */
1180 p->curr_chain_key = 0;
1181 p->lockdep_recursion = 0;
1184 #ifdef CONFIG_DEBUG_MUTEXES
1185 p->blocked_on = NULL; /* not blocked yet */
1188 /* Perform scheduler related setup. Assign this task to a CPU. */
1189 sched_fork(p, clone_flags);
1191 if ((retval = security_task_alloc(p)))
1192 goto bad_fork_cleanup_policy;
1193 if ((retval = audit_alloc(p)))
1194 goto bad_fork_cleanup_security;
1195 /* copy all the process information */
1196 if ((retval = copy_semundo(clone_flags, p)))
1197 goto bad_fork_cleanup_audit;
1198 if ((retval = copy_files(clone_flags, p)))
1199 goto bad_fork_cleanup_semundo;
1200 if ((retval = copy_fs(clone_flags, p)))
1201 goto bad_fork_cleanup_files;
1202 if ((retval = copy_sighand(clone_flags, p)))
1203 goto bad_fork_cleanup_fs;
1204 if ((retval = copy_signal(clone_flags, p)))
1205 goto bad_fork_cleanup_sighand;
1206 if ((retval = copy_mm(clone_flags, p)))
1207 goto bad_fork_cleanup_signal;
1208 if ((retval = copy_keys(clone_flags, p)))
1209 goto bad_fork_cleanup_mm;
1210 if ((retval = copy_namespaces(clone_flags, p)))
1211 goto bad_fork_cleanup_keys;
1212 if ((retval = copy_io(clone_flags, p)))
1213 goto bad_fork_cleanup_namespaces;
1214 retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
1216 goto bad_fork_cleanup_io;
1218 if (pid != &init_struct_pid) {
1220 pid = alloc_pid(task_active_pid_ns(p));
1222 goto bad_fork_cleanup_io;
1224 if (clone_flags & CLONE_NEWPID) {
1225 retval = pid_ns_prepare_proc(task_active_pid_ns(p));
1227 goto bad_fork_free_pid;
1231 p->pid = pid_nr(pid);
1233 if (clone_flags & CLONE_THREAD)
1234 p->tgid = current->tgid;
1236 p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1238 * Clear TID on mm_release()?
1240 p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
1242 p->robust_list = NULL;
1243 #ifdef CONFIG_COMPAT
1244 p->compat_robust_list = NULL;
1246 INIT_LIST_HEAD(&p->pi_state_list);
1247 p->pi_state_cache = NULL;
1250 * sigaltstack should be cleared when sharing the same VM
1252 if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
1253 p->sas_ss_sp = p->sas_ss_size = 0;
1256 * Syscall tracing should be turned off in the child regardless
1259 clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
1260 #ifdef TIF_SYSCALL_EMU
1261 clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
1263 clear_all_latency_tracing(p);
1265 /* Our parent execution domain becomes current domain
1266 These must match for thread signalling to apply */
1267 p->parent_exec_id = p->self_exec_id;
1269 /* ok, now we should be set up.. */
1270 p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
1271 p->pdeath_signal = 0;
1275 * Ok, make it visible to the rest of the system.
1276 * We dont wake it up yet.
1278 p->group_leader = p;
1279 INIT_LIST_HEAD(&p->thread_group);
1280 INIT_LIST_HEAD(&p->ptrace_children);
1281 INIT_LIST_HEAD(&p->ptrace_list);
1283 /* Now that the task is set up, run cgroup callbacks if
1284 * necessary. We need to run them before the task is visible
1285 * on the tasklist. */
1286 cgroup_fork_callbacks(p);
1287 cgroup_callbacks_done = 1;
1289 /* Need tasklist lock for parent etc handling! */
1290 write_lock_irq(&tasklist_lock);
1293 * The task hasn't been attached yet, so its cpus_allowed mask will
1294 * not be changed, nor will its assigned CPU.
1296 * The cpus_allowed mask of the parent may have changed after it was
1297 * copied first time - so re-copy it here, then check the child's CPU
1298 * to ensure it is on a valid CPU (and if not, just force it back to
1299 * parent's CPU). This avoids alot of nasty races.
1301 p->cpus_allowed = current->cpus_allowed;
1302 p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed;
1303 if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
1304 !cpu_online(task_cpu(p))))
1305 set_task_cpu(p, smp_processor_id());
1307 /* CLONE_PARENT re-uses the old parent */
1308 if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
1309 p->real_parent = current->real_parent;
1311 p->real_parent = current;
1312 p->parent = p->real_parent;
1314 spin_lock(¤t->sighand->siglock);
1317 * Process group and session signals need to be delivered to just the
1318 * parent before the fork or both the parent and the child after the
1319 * fork. Restart if a signal comes in before we add the new process to
1320 * it's process group.
1321 * A fatal signal pending means that current will exit, so the new
1322 * thread can't slip out of an OOM kill (or normal SIGKILL).
1324 recalc_sigpending();
1325 if (signal_pending(current)) {
1326 spin_unlock(¤t->sighand->siglock);
1327 write_unlock_irq(&tasklist_lock);
1328 retval = -ERESTARTNOINTR;
1329 goto bad_fork_free_pid;
1332 if (clone_flags & CLONE_THREAD) {
1333 p->group_leader = current->group_leader;
1334 list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
1336 if (!cputime_eq(current->signal->it_virt_expires,
1338 !cputime_eq(current->signal->it_prof_expires,
1340 current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY ||
1341 !list_empty(¤t->signal->cpu_timers[0]) ||
1342 !list_empty(¤t->signal->cpu_timers[1]) ||
1343 !list_empty(¤t->signal->cpu_timers[2])) {
1345 * Have child wake up on its first tick to check
1346 * for process CPU timers.
1348 p->it_prof_expires = jiffies_to_cputime(1);
1352 if (likely(p->pid)) {
1354 if (unlikely(p->ptrace & PT_PTRACED))
1355 __ptrace_link(p, current->parent);
1357 if (thread_group_leader(p)) {
1358 if (clone_flags & CLONE_NEWPID)
1359 p->nsproxy->pid_ns->child_reaper = p;
1361 p->signal->leader_pid = pid;
1362 p->signal->tty = current->signal->tty;
1363 set_task_pgrp(p, task_pgrp_nr(current));
1364 set_task_session(p, task_session_nr(current));
1365 attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
1366 attach_pid(p, PIDTYPE_SID, task_session(current));
1367 list_add_tail_rcu(&p->tasks, &init_task.tasks);
1368 __get_cpu_var(process_counts)++;
1370 attach_pid(p, PIDTYPE_PID, pid);
1375 spin_unlock(¤t->sighand->siglock);
1376 write_unlock_irq(&tasklist_lock);
1377 proc_fork_connector(p);
1378 cgroup_post_fork(p);
1382 if (pid != &init_struct_pid)
1384 bad_fork_cleanup_io:
1385 put_io_context(p->io_context);
1386 bad_fork_cleanup_namespaces:
1387 exit_task_namespaces(p);
1388 bad_fork_cleanup_keys:
1390 bad_fork_cleanup_mm:
1393 bad_fork_cleanup_signal:
1395 bad_fork_cleanup_sighand:
1396 __cleanup_sighand(p->sighand);
1397 bad_fork_cleanup_fs:
1398 exit_fs(p); /* blocking */
1399 bad_fork_cleanup_files:
1400 exit_files(p); /* blocking */
1401 bad_fork_cleanup_semundo:
1403 bad_fork_cleanup_audit:
1405 bad_fork_cleanup_security:
1406 security_task_free(p);
1407 bad_fork_cleanup_policy:
1409 mpol_free(p->mempolicy);
1410 bad_fork_cleanup_cgroup:
1412 cgroup_exit(p, cgroup_callbacks_done);
1413 delayacct_tsk_free(p);
1415 module_put(p->binfmt->module);
1416 bad_fork_cleanup_put_domain:
1417 module_put(task_thread_info(p)->exec_domain->module);
1418 bad_fork_cleanup_count:
1419 put_group_info(p->group_info);
1420 atomic_dec(&p->user->processes);
1425 return ERR_PTR(retval);
1428 noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
1430 memset(regs, 0, sizeof(struct pt_regs));
1434 struct task_struct * __cpuinit fork_idle(int cpu)
1436 struct task_struct *task;
1437 struct pt_regs regs;
1439 task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL,
1442 init_idle(task, cpu);
1447 static int fork_traceflag(unsigned clone_flags)
1449 if (clone_flags & CLONE_UNTRACED)
1451 else if (clone_flags & CLONE_VFORK) {
1452 if (current->ptrace & PT_TRACE_VFORK)
1453 return PTRACE_EVENT_VFORK;
1454 } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
1455 if (current->ptrace & PT_TRACE_CLONE)
1456 return PTRACE_EVENT_CLONE;
1457 } else if (current->ptrace & PT_TRACE_FORK)
1458 return PTRACE_EVENT_FORK;
1464 * Ok, this is the main fork-routine.
1466 * It copies the process, and if successful kick-starts
1467 * it and waits for it to finish using the VM if required.
1469 long do_fork(unsigned long clone_flags,
1470 unsigned long stack_start,
1471 struct pt_regs *regs,
1472 unsigned long stack_size,
1473 int __user *parent_tidptr,
1474 int __user *child_tidptr)
1476 struct task_struct *p;
1481 * We hope to recycle these flags after 2.6.26
1483 if (unlikely(clone_flags & CLONE_STOPPED)) {
1484 static int __read_mostly count = 100;
1486 if (count > 0 && printk_ratelimit()) {
1487 char comm[TASK_COMM_LEN];
1490 printk(KERN_INFO "fork(): process `%s' used deprecated "
1491 "clone flags 0x%lx\n",
1492 get_task_comm(comm, current),
1493 clone_flags & CLONE_STOPPED);
1497 if (unlikely(current->ptrace)) {
1498 trace = fork_traceflag (clone_flags);
1500 clone_flags |= CLONE_PTRACE;
1503 p = copy_process(clone_flags, stack_start, regs, stack_size,
1504 child_tidptr, NULL);
1506 * Do this prior waking up the new thread - the thread pointer
1507 * might get invalid after that point, if the thread exits quickly.
1510 struct completion vfork;
1512 nr = task_pid_vnr(p);
1514 if (clone_flags & CLONE_PARENT_SETTID)
1515 put_user(nr, parent_tidptr);
1517 if (clone_flags & CLONE_VFORK) {
1518 p->vfork_done = &vfork;
1519 init_completion(&vfork);
1522 if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
1524 * We'll start up with an immediate SIGSTOP.
1526 sigaddset(&p->pending.signal, SIGSTOP);
1527 set_tsk_thread_flag(p, TIF_SIGPENDING);
1530 if (!(clone_flags & CLONE_STOPPED))
1531 wake_up_new_task(p, clone_flags);
1533 __set_task_state(p, TASK_STOPPED);
1535 if (unlikely (trace)) {
1536 current->ptrace_message = nr;
1537 ptrace_notify ((trace << 8) | SIGTRAP);
1540 if (clone_flags & CLONE_VFORK) {
1541 freezer_do_not_count();
1542 wait_for_completion(&vfork);
1544 if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) {
1545 current->ptrace_message = nr;
1546 ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
1555 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
1556 #define ARCH_MIN_MMSTRUCT_ALIGN 0
1559 static void sighand_ctor(struct kmem_cache *cachep, void *data)
1561 struct sighand_struct *sighand = data;
1563 spin_lock_init(&sighand->siglock);
1564 init_waitqueue_head(&sighand->signalfd_wqh);
1567 void __init proc_caches_init(void)
1569 sighand_cachep = kmem_cache_create("sighand_cache",
1570 sizeof(struct sighand_struct), 0,
1571 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU,
1573 signal_cachep = kmem_cache_create("signal_cache",
1574 sizeof(struct signal_struct), 0,
1575 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1576 files_cachep = kmem_cache_create("files_cache",
1577 sizeof(struct files_struct), 0,
1578 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1579 fs_cachep = kmem_cache_create("fs_cache",
1580 sizeof(struct fs_struct), 0,
1581 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1582 vm_area_cachep = kmem_cache_create("vm_area_struct",
1583 sizeof(struct vm_area_struct), 0,
1585 mm_cachep = kmem_cache_create("mm_struct",
1586 sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
1587 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1591 * Check constraints on flags passed to the unshare system call and
1592 * force unsharing of additional process context as appropriate.
1594 static void check_unshare_flags(unsigned long *flags_ptr)
1597 * If unsharing a thread from a thread group, must also
1600 if (*flags_ptr & CLONE_THREAD)
1601 *flags_ptr |= CLONE_VM;
1604 * If unsharing vm, must also unshare signal handlers.
1606 if (*flags_ptr & CLONE_VM)
1607 *flags_ptr |= CLONE_SIGHAND;
1610 * If unsharing signal handlers and the task was created
1611 * using CLONE_THREAD, then must unshare the thread
1613 if ((*flags_ptr & CLONE_SIGHAND) &&
1614 (atomic_read(¤t->signal->count) > 1))
1615 *flags_ptr |= CLONE_THREAD;
1618 * If unsharing namespace, must also unshare filesystem information.
1620 if (*flags_ptr & CLONE_NEWNS)
1621 *flags_ptr |= CLONE_FS;
1625 * Unsharing of tasks created with CLONE_THREAD is not supported yet
1627 static int unshare_thread(unsigned long unshare_flags)
1629 if (unshare_flags & CLONE_THREAD)
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) &&
1643 (fs && atomic_read(&fs->count) > 1)) {
1644 *new_fsp = __copy_fs_struct(current->fs);
1653 * Unsharing of sighand is not supported yet
1655 static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
1657 struct sighand_struct *sigh = current->sighand;
1659 if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1)
1666 * Unshare vm if it is being shared
1668 static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
1670 struct mm_struct *mm = current->mm;
1672 if ((unshare_flags & CLONE_VM) &&
1673 (mm && atomic_read(&mm->mm_users) > 1)) {
1681 * Unshare file descriptor table if it is being shared
1683 static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
1685 struct files_struct *fd = current->files;
1688 if ((unshare_flags & CLONE_FILES) &&
1689 (fd && atomic_read(&fd->count) > 1)) {
1690 *new_fdp = dup_fd(fd, &error);
1699 * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not
1702 static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp)
1704 if (unshare_flags & CLONE_SYSVSEM)
1711 * unshare allows a process to 'unshare' part of the process
1712 * context which was originally shared using clone. copy_*
1713 * functions used by do_fork() cannot be used here directly
1714 * because they modify an inactive task_struct that is being
1715 * constructed. Here we are modifying the current, active,
1718 asmlinkage long sys_unshare(unsigned long unshare_flags)
1721 struct fs_struct *fs, *new_fs = NULL;
1722 struct sighand_struct *new_sigh = NULL;
1723 struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
1724 struct files_struct *fd, *new_fd = NULL;
1725 struct sem_undo_list *new_ulist = NULL;
1726 struct nsproxy *new_nsproxy = NULL;
1728 check_unshare_flags(&unshare_flags);
1730 /* Return -EINVAL for all unsupported flags */
1732 if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
1733 CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
1734 CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER|
1736 goto bad_unshare_out;
1738 if ((err = unshare_thread(unshare_flags)))
1739 goto bad_unshare_out;
1740 if ((err = unshare_fs(unshare_flags, &new_fs)))
1741 goto bad_unshare_cleanup_thread;
1742 if ((err = unshare_sighand(unshare_flags, &new_sigh)))
1743 goto bad_unshare_cleanup_fs;
1744 if ((err = unshare_vm(unshare_flags, &new_mm)))
1745 goto bad_unshare_cleanup_sigh;
1746 if ((err = unshare_fd(unshare_flags, &new_fd)))
1747 goto bad_unshare_cleanup_vm;
1748 if ((err = unshare_semundo(unshare_flags, &new_ulist)))
1749 goto bad_unshare_cleanup_fd;
1750 if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
1752 goto bad_unshare_cleanup_semundo;
1754 if (new_fs || new_mm || new_fd || new_ulist || new_nsproxy) {
1757 switch_task_namespaces(current, new_nsproxy);
1765 current->fs = new_fs;
1771 active_mm = current->active_mm;
1772 current->mm = new_mm;
1773 current->active_mm = new_mm;
1774 activate_mm(active_mm, new_mm);
1779 fd = current->files;
1780 current->files = new_fd;
1784 task_unlock(current);
1788 put_nsproxy(new_nsproxy);
1790 bad_unshare_cleanup_semundo:
1791 bad_unshare_cleanup_fd:
1793 put_files_struct(new_fd);
1795 bad_unshare_cleanup_vm:
1799 bad_unshare_cleanup_sigh:
1801 if (atomic_dec_and_test(&new_sigh->count))
1802 kmem_cache_free(sighand_cachep, new_sigh);
1804 bad_unshare_cleanup_fs:
1806 put_fs_struct(new_fs);
1808 bad_unshare_cleanup_thread: