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/sched/autogroup.h>
16 #include <linux/sched/mm.h>
17 #include <linux/sched/coredump.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/numa_balancing.h>
20 #include <linux/sched/stat.h>
21 #include <linux/sched/task.h>
22 #include <linux/sched/task_stack.h>
23 #include <linux/sched/cputime.h>
24 #include <linux/rtmutex.h>
25 #include <linux/init.h>
26 #include <linux/unistd.h>
27 #include <linux/module.h>
28 #include <linux/vmalloc.h>
29 #include <linux/completion.h>
30 #include <linux/personality.h>
31 #include <linux/mempolicy.h>
32 #include <linux/sem.h>
33 #include <linux/file.h>
34 #include <linux/fdtable.h>
35 #include <linux/iocontext.h>
36 #include <linux/key.h>
37 #include <linux/binfmts.h>
38 #include <linux/mman.h>
39 #include <linux/mmu_notifier.h>
40 #include <linux/hmm.h>
43 #include <linux/vmacache.h>
44 #include <linux/nsproxy.h>
45 #include <linux/capability.h>
46 #include <linux/cpu.h>
47 #include <linux/cgroup.h>
48 #include <linux/security.h>
49 #include <linux/hugetlb.h>
50 #include <linux/seccomp.h>
51 #include <linux/swap.h>
52 #include <linux/syscalls.h>
53 #include <linux/jiffies.h>
54 #include <linux/futex.h>
55 #include <linux/compat.h>
56 #include <linux/kthread.h>
57 #include <linux/task_io_accounting_ops.h>
58 #include <linux/rcupdate.h>
59 #include <linux/ptrace.h>
60 #include <linux/mount.h>
61 #include <linux/audit.h>
62 #include <linux/memcontrol.h>
63 #include <linux/ftrace.h>
64 #include <linux/proc_fs.h>
65 #include <linux/profile.h>
66 #include <linux/rmap.h>
67 #include <linux/ksm.h>
68 #include <linux/acct.h>
69 #include <linux/userfaultfd_k.h>
70 #include <linux/tsacct_kern.h>
71 #include <linux/cn_proc.h>
72 #include <linux/freezer.h>
73 #include <linux/delayacct.h>
74 #include <linux/taskstats_kern.h>
75 #include <linux/random.h>
76 #include <linux/tty.h>
77 #include <linux/blkdev.h>
78 #include <linux/fs_struct.h>
79 #include <linux/magic.h>
80 #include <linux/sched/mm.h>
81 #include <linux/perf_event.h>
82 #include <linux/posix-timers.h>
83 #include <linux/user-return-notifier.h>
84 #include <linux/oom.h>
85 #include <linux/khugepaged.h>
86 #include <linux/signalfd.h>
87 #include <linux/uprobes.h>
88 #include <linux/aio.h>
89 #include <linux/compiler.h>
90 #include <linux/sysctl.h>
91 #include <linux/kcov.h>
92 #include <linux/livepatch.h>
93 #include <linux/thread_info.h>
95 #include <asm/pgtable.h>
96 #include <asm/pgalloc.h>
97 #include <linux/uaccess.h>
98 #include <asm/mmu_context.h>
99 #include <asm/cacheflush.h>
100 #include <asm/tlbflush.h>
102 #include <trace/events/sched.h>
104 #define CREATE_TRACE_POINTS
105 #include <trace/events/task.h>
108 * Minimum number of threads to boot the kernel
110 #define MIN_THREADS 20
113 * Maximum number of threads
115 #define MAX_THREADS FUTEX_TID_MASK
118 * Protected counters by write_lock_irq(&tasklist_lock)
120 unsigned long total_forks
; /* Handle normal Linux uptimes. */
121 int nr_threads
; /* The idle threads do not count.. */
123 int max_threads
; /* tunable limit on nr_threads */
125 DEFINE_PER_CPU(unsigned long, process_counts
) = 0;
127 __cacheline_aligned
DEFINE_RWLOCK(tasklist_lock
); /* outer */
129 #ifdef CONFIG_PROVE_RCU
130 int lockdep_tasklist_lock_is_held(void)
132 return lockdep_is_held(&tasklist_lock
);
134 EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held
);
135 #endif /* #ifdef CONFIG_PROVE_RCU */
137 int nr_processes(void)
142 for_each_possible_cpu(cpu
)
143 total
+= per_cpu(process_counts
, cpu
);
148 void __weak
arch_release_task_struct(struct task_struct
*tsk
)
152 #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
153 static struct kmem_cache
*task_struct_cachep
;
155 static inline struct task_struct
*alloc_task_struct_node(int node
)
157 return kmem_cache_alloc_node(task_struct_cachep
, GFP_KERNEL
, node
);
160 static inline void free_task_struct(struct task_struct
*tsk
)
162 kmem_cache_free(task_struct_cachep
, tsk
);
166 void __weak
arch_release_thread_stack(unsigned long *stack
)
170 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
173 * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
174 * kmemcache based allocator.
176 # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
178 #ifdef CONFIG_VMAP_STACK
180 * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
181 * flush. Try to minimize the number of calls by caching stacks.
183 #define NR_CACHED_STACKS 2
184 static DEFINE_PER_CPU(struct vm_struct
*, cached_stacks
[NR_CACHED_STACKS
]);
186 static int free_vm_stack_cache(unsigned int cpu
)
188 struct vm_struct
**cached_vm_stacks
= per_cpu_ptr(cached_stacks
, cpu
);
191 for (i
= 0; i
< NR_CACHED_STACKS
; i
++) {
192 struct vm_struct
*vm_stack
= cached_vm_stacks
[i
];
197 vfree(vm_stack
->addr
);
198 cached_vm_stacks
[i
] = NULL
;
205 static unsigned long *alloc_thread_stack_node(struct task_struct
*tsk
, int node
)
207 #ifdef CONFIG_VMAP_STACK
211 for (i
= 0; i
< NR_CACHED_STACKS
; i
++) {
214 s
= this_cpu_xchg(cached_stacks
[i
], NULL
);
219 #ifdef CONFIG_DEBUG_KMEMLEAK
220 /* Clear stale pointers from reused stack. */
221 memset(s
->addr
, 0, THREAD_SIZE
);
223 tsk
->stack_vm_area
= s
;
227 stack
= __vmalloc_node_range(THREAD_SIZE
, THREAD_ALIGN
,
228 VMALLOC_START
, VMALLOC_END
,
231 0, node
, __builtin_return_address(0));
234 * We can't call find_vm_area() in interrupt context, and
235 * free_thread_stack() can be called in interrupt context,
236 * so cache the vm_struct.
239 tsk
->stack_vm_area
= find_vm_area(stack
);
242 struct page
*page
= alloc_pages_node(node
, THREADINFO_GFP
,
245 return page
? page_address(page
) : NULL
;
249 static inline void free_thread_stack(struct task_struct
*tsk
)
251 #ifdef CONFIG_VMAP_STACK
252 if (task_stack_vm_area(tsk
)) {
255 for (i
= 0; i
< NR_CACHED_STACKS
; i
++) {
256 if (this_cpu_cmpxchg(cached_stacks
[i
],
257 NULL
, tsk
->stack_vm_area
) != NULL
)
263 vfree_atomic(tsk
->stack
);
268 __free_pages(virt_to_page(tsk
->stack
), THREAD_SIZE_ORDER
);
271 static struct kmem_cache
*thread_stack_cache
;
273 static unsigned long *alloc_thread_stack_node(struct task_struct
*tsk
,
276 return kmem_cache_alloc_node(thread_stack_cache
, THREADINFO_GFP
, node
);
279 static void free_thread_stack(struct task_struct
*tsk
)
281 kmem_cache_free(thread_stack_cache
, tsk
->stack
);
284 void thread_stack_cache_init(void)
286 thread_stack_cache
= kmem_cache_create("thread_stack", THREAD_SIZE
,
287 THREAD_SIZE
, 0, NULL
);
288 BUG_ON(thread_stack_cache
== NULL
);
293 /* SLAB cache for signal_struct structures (tsk->signal) */
294 static struct kmem_cache
*signal_cachep
;
296 /* SLAB cache for sighand_struct structures (tsk->sighand) */
297 struct kmem_cache
*sighand_cachep
;
299 /* SLAB cache for files_struct structures (tsk->files) */
300 struct kmem_cache
*files_cachep
;
302 /* SLAB cache for fs_struct structures (tsk->fs) */
303 struct kmem_cache
*fs_cachep
;
305 /* SLAB cache for vm_area_struct structures */
306 struct kmem_cache
*vm_area_cachep
;
308 /* SLAB cache for mm_struct structures (tsk->mm) */
309 static struct kmem_cache
*mm_cachep
;
311 static void account_kernel_stack(struct task_struct
*tsk
, int account
)
313 void *stack
= task_stack_page(tsk
);
314 struct vm_struct
*vm
= task_stack_vm_area(tsk
);
316 BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK
) && PAGE_SIZE
% 1024 != 0);
321 BUG_ON(vm
->nr_pages
!= THREAD_SIZE
/ PAGE_SIZE
);
323 for (i
= 0; i
< THREAD_SIZE
/ PAGE_SIZE
; i
++) {
324 mod_zone_page_state(page_zone(vm
->pages
[i
]),
326 PAGE_SIZE
/ 1024 * account
);
329 /* All stack pages belong to the same memcg. */
330 mod_memcg_page_state(vm
->pages
[0], MEMCG_KERNEL_STACK_KB
,
331 account
* (THREAD_SIZE
/ 1024));
334 * All stack pages are in the same zone and belong to the
337 struct page
*first_page
= virt_to_page(stack
);
339 mod_zone_page_state(page_zone(first_page
), NR_KERNEL_STACK_KB
,
340 THREAD_SIZE
/ 1024 * account
);
342 mod_memcg_page_state(first_page
, MEMCG_KERNEL_STACK_KB
,
343 account
* (THREAD_SIZE
/ 1024));
347 static void release_task_stack(struct task_struct
*tsk
)
349 if (WARN_ON(tsk
->state
!= TASK_DEAD
))
350 return; /* Better to leak the stack than to free prematurely */
352 account_kernel_stack(tsk
, -1);
353 arch_release_thread_stack(tsk
->stack
);
354 free_thread_stack(tsk
);
356 #ifdef CONFIG_VMAP_STACK
357 tsk
->stack_vm_area
= NULL
;
361 #ifdef CONFIG_THREAD_INFO_IN_TASK
362 void put_task_stack(struct task_struct
*tsk
)
364 if (atomic_dec_and_test(&tsk
->stack_refcount
))
365 release_task_stack(tsk
);
369 void free_task(struct task_struct
*tsk
)
371 #ifndef CONFIG_THREAD_INFO_IN_TASK
373 * The task is finally done with both the stack and thread_info,
376 release_task_stack(tsk
);
379 * If the task had a separate stack allocation, it should be gone
382 WARN_ON_ONCE(atomic_read(&tsk
->stack_refcount
) != 0);
384 rt_mutex_debug_task_free(tsk
);
385 ftrace_graph_exit_task(tsk
);
386 put_seccomp_filter(tsk
);
387 arch_release_task_struct(tsk
);
388 if (tsk
->flags
& PF_KTHREAD
)
389 free_kthread_struct(tsk
);
390 free_task_struct(tsk
);
392 EXPORT_SYMBOL(free_task
);
395 static __latent_entropy
int dup_mmap(struct mm_struct
*mm
,
396 struct mm_struct
*oldmm
)
398 struct vm_area_struct
*mpnt
, *tmp
, *prev
, **pprev
;
399 struct rb_node
**rb_link
, *rb_parent
;
401 unsigned long charge
;
404 uprobe_start_dup_mmap();
405 if (down_write_killable(&oldmm
->mmap_sem
)) {
407 goto fail_uprobe_end
;
409 flush_cache_dup_mm(oldmm
);
410 uprobe_dup_mmap(oldmm
, mm
);
412 * Not linked in yet - no deadlock potential:
414 down_write_nested(&mm
->mmap_sem
, SINGLE_DEPTH_NESTING
);
416 /* No ordering required: file already has been exposed. */
417 RCU_INIT_POINTER(mm
->exe_file
, get_mm_exe_file(oldmm
));
419 mm
->total_vm
= oldmm
->total_vm
;
420 mm
->data_vm
= oldmm
->data_vm
;
421 mm
->exec_vm
= oldmm
->exec_vm
;
422 mm
->stack_vm
= oldmm
->stack_vm
;
424 rb_link
= &mm
->mm_rb
.rb_node
;
427 retval
= ksm_fork(mm
, oldmm
);
430 retval
= khugepaged_fork(mm
, oldmm
);
435 for (mpnt
= oldmm
->mmap
; mpnt
; mpnt
= mpnt
->vm_next
) {
438 if (mpnt
->vm_flags
& VM_DONTCOPY
) {
439 vm_stat_account(mm
, mpnt
->vm_flags
, -vma_pages(mpnt
));
443 if (mpnt
->vm_flags
& VM_ACCOUNT
) {
444 unsigned long len
= vma_pages(mpnt
);
446 if (security_vm_enough_memory_mm(oldmm
, len
)) /* sic */
450 tmp
= kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
454 INIT_LIST_HEAD(&tmp
->anon_vma_chain
);
455 retval
= vma_dup_policy(mpnt
, tmp
);
457 goto fail_nomem_policy
;
459 retval
= dup_userfaultfd(tmp
, &uf
);
461 goto fail_nomem_anon_vma_fork
;
462 if (tmp
->vm_flags
& VM_WIPEONFORK
) {
463 /* VM_WIPEONFORK gets a clean slate in the child. */
464 tmp
->anon_vma
= NULL
;
465 if (anon_vma_prepare(tmp
))
466 goto fail_nomem_anon_vma_fork
;
467 } else if (anon_vma_fork(tmp
, mpnt
))
468 goto fail_nomem_anon_vma_fork
;
469 tmp
->vm_flags
&= ~(VM_LOCKED
| VM_LOCKONFAULT
);
470 tmp
->vm_next
= tmp
->vm_prev
= NULL
;
473 struct inode
*inode
= file_inode(file
);
474 struct address_space
*mapping
= file
->f_mapping
;
477 if (tmp
->vm_flags
& VM_DENYWRITE
)
478 atomic_dec(&inode
->i_writecount
);
479 i_mmap_lock_write(mapping
);
480 if (tmp
->vm_flags
& VM_SHARED
)
481 atomic_inc(&mapping
->i_mmap_writable
);
482 flush_dcache_mmap_lock(mapping
);
483 /* insert tmp into the share list, just after mpnt */
484 vma_interval_tree_insert_after(tmp
, mpnt
,
486 flush_dcache_mmap_unlock(mapping
);
487 i_mmap_unlock_write(mapping
);
491 * Clear hugetlb-related page reserves for children. This only
492 * affects MAP_PRIVATE mappings. Faults generated by the child
493 * are not guaranteed to succeed, even if read-only
495 if (is_vm_hugetlb_page(tmp
))
496 reset_vma_resv_huge_pages(tmp
);
499 * Link in the new vma and copy the page table entries.
502 pprev
= &tmp
->vm_next
;
506 __vma_link_rb(mm
, tmp
, rb_link
, rb_parent
);
507 rb_link
= &tmp
->vm_rb
.rb_right
;
508 rb_parent
= &tmp
->vm_rb
;
511 if (!(tmp
->vm_flags
& VM_WIPEONFORK
))
512 retval
= copy_page_range(mm
, oldmm
, mpnt
);
514 if (tmp
->vm_ops
&& tmp
->vm_ops
->open
)
515 tmp
->vm_ops
->open(tmp
);
520 /* a new mm has just been created */
521 arch_dup_mmap(oldmm
, mm
);
524 up_write(&mm
->mmap_sem
);
526 up_write(&oldmm
->mmap_sem
);
527 dup_userfaultfd_complete(&uf
);
529 uprobe_end_dup_mmap();
531 fail_nomem_anon_vma_fork
:
532 mpol_put(vma_policy(tmp
));
534 kmem_cache_free(vm_area_cachep
, tmp
);
537 vm_unacct_memory(charge
);
541 static inline int mm_alloc_pgd(struct mm_struct
*mm
)
543 mm
->pgd
= pgd_alloc(mm
);
544 if (unlikely(!mm
->pgd
))
549 static inline void mm_free_pgd(struct mm_struct
*mm
)
551 pgd_free(mm
, mm
->pgd
);
554 static int dup_mmap(struct mm_struct
*mm
, struct mm_struct
*oldmm
)
556 down_write(&oldmm
->mmap_sem
);
557 RCU_INIT_POINTER(mm
->exe_file
, get_mm_exe_file(oldmm
));
558 up_write(&oldmm
->mmap_sem
);
561 #define mm_alloc_pgd(mm) (0)
562 #define mm_free_pgd(mm)
563 #endif /* CONFIG_MMU */
565 static void check_mm(struct mm_struct
*mm
)
569 for (i
= 0; i
< NR_MM_COUNTERS
; i
++) {
570 long x
= atomic_long_read(&mm
->rss_stat
.count
[i
]);
573 printk(KERN_ALERT
"BUG: Bad rss-counter state "
574 "mm:%p idx:%d val:%ld\n", mm
, i
, x
);
577 if (mm_pgtables_bytes(mm
))
578 pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
579 mm_pgtables_bytes(mm
));
581 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
582 VM_BUG_ON_MM(mm
->pmd_huge_pte
, mm
);
586 #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
587 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
590 * Called when the last reference to the mm
591 * is dropped: either by a lazy thread or by
592 * mmput. Free the page directory and the mm.
594 static void __mmdrop(struct mm_struct
*mm
)
596 BUG_ON(mm
== &init_mm
);
600 mmu_notifier_mm_destroy(mm
);
602 put_user_ns(mm
->user_ns
);
606 void mmdrop(struct mm_struct
*mm
)
608 if (unlikely(atomic_dec_and_test(&mm
->mm_count
)))
611 EXPORT_SYMBOL_GPL(mmdrop
);
613 static void mmdrop_async_fn(struct work_struct
*work
)
615 struct mm_struct
*mm
;
617 mm
= container_of(work
, struct mm_struct
, async_put_work
);
621 static void mmdrop_async(struct mm_struct
*mm
)
623 if (unlikely(atomic_dec_and_test(&mm
->mm_count
))) {
624 INIT_WORK(&mm
->async_put_work
, mmdrop_async_fn
);
625 schedule_work(&mm
->async_put_work
);
629 static inline void free_signal_struct(struct signal_struct
*sig
)
631 taskstats_tgid_free(sig
);
632 sched_autogroup_exit(sig
);
634 * __mmdrop is not safe to call from softirq context on x86 due to
635 * pgd_dtor so postpone it to the async context
638 mmdrop_async(sig
->oom_mm
);
639 kmem_cache_free(signal_cachep
, sig
);
642 static inline void put_signal_struct(struct signal_struct
*sig
)
644 if (atomic_dec_and_test(&sig
->sigcnt
))
645 free_signal_struct(sig
);
648 void __put_task_struct(struct task_struct
*tsk
)
650 WARN_ON(!tsk
->exit_state
);
651 WARN_ON(atomic_read(&tsk
->usage
));
652 WARN_ON(tsk
== current
);
656 security_task_free(tsk
);
658 delayacct_tsk_free(tsk
);
659 put_signal_struct(tsk
->signal
);
661 if (!profile_handoff_task(tsk
))
664 EXPORT_SYMBOL_GPL(__put_task_struct
);
666 void __init __weak
arch_task_cache_init(void) { }
671 static void set_max_threads(unsigned int max_threads_suggested
)
676 * The number of threads shall be limited such that the thread
677 * structures may only consume a small part of the available memory.
679 if (fls64(totalram_pages
) + fls64(PAGE_SIZE
) > 64)
680 threads
= MAX_THREADS
;
682 threads
= div64_u64((u64
) totalram_pages
* (u64
) PAGE_SIZE
,
683 (u64
) THREAD_SIZE
* 8UL);
685 if (threads
> max_threads_suggested
)
686 threads
= max_threads_suggested
;
688 max_threads
= clamp_t(u64
, threads
, MIN_THREADS
, MAX_THREADS
);
691 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
692 /* Initialized by the architecture: */
693 int arch_task_struct_size __read_mostly
;
696 void __init
fork_init(void)
699 #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
700 #ifndef ARCH_MIN_TASKALIGN
701 #define ARCH_MIN_TASKALIGN 0
703 int align
= max_t(int, L1_CACHE_BYTES
, ARCH_MIN_TASKALIGN
);
705 /* create a slab on which task_structs can be allocated */
706 task_struct_cachep
= kmem_cache_create("task_struct",
707 arch_task_struct_size
, align
,
708 SLAB_PANIC
|SLAB_ACCOUNT
, NULL
);
711 /* do the arch specific task caches init */
712 arch_task_cache_init();
714 set_max_threads(MAX_THREADS
);
716 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_cur
= max_threads
/2;
717 init_task
.signal
->rlim
[RLIMIT_NPROC
].rlim_max
= max_threads
/2;
718 init_task
.signal
->rlim
[RLIMIT_SIGPENDING
] =
719 init_task
.signal
->rlim
[RLIMIT_NPROC
];
721 for (i
= 0; i
< UCOUNT_COUNTS
; i
++) {
722 init_user_ns
.ucount_max
[i
] = max_threads
/2;
725 #ifdef CONFIG_VMAP_STACK
726 cpuhp_setup_state(CPUHP_BP_PREPARE_DYN
, "fork:vm_stack_cache",
727 NULL
, free_vm_stack_cache
);
730 lockdep_init_task(&init_task
);
733 int __weak
arch_dup_task_struct(struct task_struct
*dst
,
734 struct task_struct
*src
)
740 void set_task_stack_end_magic(struct task_struct
*tsk
)
742 unsigned long *stackend
;
744 stackend
= end_of_stack(tsk
);
745 *stackend
= STACK_END_MAGIC
; /* for overflow detection */
748 static struct task_struct
*dup_task_struct(struct task_struct
*orig
, int node
)
750 struct task_struct
*tsk
;
751 unsigned long *stack
;
752 struct vm_struct
*stack_vm_area
;
755 if (node
== NUMA_NO_NODE
)
756 node
= tsk_fork_get_node(orig
);
757 tsk
= alloc_task_struct_node(node
);
761 stack
= alloc_thread_stack_node(tsk
, node
);
765 stack_vm_area
= task_stack_vm_area(tsk
);
767 err
= arch_dup_task_struct(tsk
, orig
);
770 * arch_dup_task_struct() clobbers the stack-related fields. Make
771 * sure they're properly initialized before using any stack-related
775 #ifdef CONFIG_VMAP_STACK
776 tsk
->stack_vm_area
= stack_vm_area
;
778 #ifdef CONFIG_THREAD_INFO_IN_TASK
779 atomic_set(&tsk
->stack_refcount
, 1);
785 #ifdef CONFIG_SECCOMP
787 * We must handle setting up seccomp filters once we're under
788 * the sighand lock in case orig has changed between now and
789 * then. Until then, filter must be NULL to avoid messing up
790 * the usage counts on the error path calling free_task.
792 tsk
->seccomp
.filter
= NULL
;
795 setup_thread_stack(tsk
, orig
);
796 clear_user_return_notifier(tsk
);
797 clear_tsk_need_resched(tsk
);
798 set_task_stack_end_magic(tsk
);
800 #ifdef CONFIG_CC_STACKPROTECTOR
801 tsk
->stack_canary
= get_random_canary();
805 * One for us, one for whoever does the "release_task()" (usually
808 atomic_set(&tsk
->usage
, 2);
809 #ifdef CONFIG_BLK_DEV_IO_TRACE
812 tsk
->splice_pipe
= NULL
;
813 tsk
->task_frag
.page
= NULL
;
814 tsk
->wake_q
.next
= NULL
;
816 account_kernel_stack(tsk
, 1);
820 #ifdef CONFIG_FAULT_INJECTION
827 free_thread_stack(tsk
);
829 free_task_struct(tsk
);
833 __cacheline_aligned_in_smp
DEFINE_SPINLOCK(mmlist_lock
);
835 static unsigned long default_dump_filter
= MMF_DUMP_FILTER_DEFAULT
;
837 static int __init
coredump_filter_setup(char *s
)
839 default_dump_filter
=
840 (simple_strtoul(s
, NULL
, 0) << MMF_DUMP_FILTER_SHIFT
) &
841 MMF_DUMP_FILTER_MASK
;
845 __setup("coredump_filter=", coredump_filter_setup
);
847 #include <linux/init_task.h>
849 static void mm_init_aio(struct mm_struct
*mm
)
852 spin_lock_init(&mm
->ioctx_lock
);
853 mm
->ioctx_table
= NULL
;
857 static void mm_init_owner(struct mm_struct
*mm
, struct task_struct
*p
)
864 static void mm_init_uprobes_state(struct mm_struct
*mm
)
866 #ifdef CONFIG_UPROBES
867 mm
->uprobes_state
.xol_area
= NULL
;
871 static struct mm_struct
*mm_init(struct mm_struct
*mm
, struct task_struct
*p
,
872 struct user_namespace
*user_ns
)
876 mm
->vmacache_seqnum
= 0;
877 atomic_set(&mm
->mm_users
, 1);
878 atomic_set(&mm
->mm_count
, 1);
879 init_rwsem(&mm
->mmap_sem
);
880 INIT_LIST_HEAD(&mm
->mmlist
);
881 mm
->core_state
= NULL
;
882 mm_pgtables_bytes_init(mm
);
886 memset(&mm
->rss_stat
, 0, sizeof(mm
->rss_stat
));
887 spin_lock_init(&mm
->page_table_lock
);
890 mm_init_owner(mm
, p
);
891 RCU_INIT_POINTER(mm
->exe_file
, NULL
);
892 mmu_notifier_mm_init(mm
);
894 init_tlb_flush_pending(mm
);
895 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
896 mm
->pmd_huge_pte
= NULL
;
898 mm_init_uprobes_state(mm
);
901 mm
->flags
= current
->mm
->flags
& MMF_INIT_MASK
;
902 mm
->def_flags
= current
->mm
->def_flags
& VM_INIT_DEF_MASK
;
904 mm
->flags
= default_dump_filter
;
908 if (mm_alloc_pgd(mm
))
911 if (init_new_context(p
, mm
))
914 mm
->user_ns
= get_user_ns(user_ns
);
925 * Allocate and initialize an mm_struct.
927 struct mm_struct
*mm_alloc(void)
929 struct mm_struct
*mm
;
935 memset(mm
, 0, sizeof(*mm
));
936 return mm_init(mm
, current
, current_user_ns());
939 static inline void __mmput(struct mm_struct
*mm
)
941 VM_BUG_ON(atomic_read(&mm
->mm_users
));
943 uprobe_clear_state(mm
);
946 khugepaged_exit(mm
); /* must run before exit_mmap */
948 mm_put_huge_zero_page(mm
);
949 set_mm_exe_file(mm
, NULL
);
950 if (!list_empty(&mm
->mmlist
)) {
951 spin_lock(&mmlist_lock
);
952 list_del(&mm
->mmlist
);
953 spin_unlock(&mmlist_lock
);
956 module_put(mm
->binfmt
->module
);
961 * Decrement the use count and release all resources for an mm.
963 void mmput(struct mm_struct
*mm
)
967 if (atomic_dec_and_test(&mm
->mm_users
))
970 EXPORT_SYMBOL_GPL(mmput
);
973 static void mmput_async_fn(struct work_struct
*work
)
975 struct mm_struct
*mm
= container_of(work
, struct mm_struct
,
981 void mmput_async(struct mm_struct
*mm
)
983 if (atomic_dec_and_test(&mm
->mm_users
)) {
984 INIT_WORK(&mm
->async_put_work
, mmput_async_fn
);
985 schedule_work(&mm
->async_put_work
);
991 * set_mm_exe_file - change a reference to the mm's executable file
993 * This changes mm's executable file (shown as symlink /proc/[pid]/exe).
995 * Main users are mmput() and sys_execve(). Callers prevent concurrent
996 * invocations: in mmput() nobody alive left, in execve task is single
997 * threaded. sys_prctl(PR_SET_MM_MAP/EXE_FILE) also needs to set the
998 * mm->exe_file, but does so without using set_mm_exe_file() in order
999 * to do avoid the need for any locks.
1001 void set_mm_exe_file(struct mm_struct
*mm
, struct file
*new_exe_file
)
1003 struct file
*old_exe_file
;
1006 * It is safe to dereference the exe_file without RCU as
1007 * this function is only called if nobody else can access
1008 * this mm -- see comment above for justification.
1010 old_exe_file
= rcu_dereference_raw(mm
->exe_file
);
1013 get_file(new_exe_file
);
1014 rcu_assign_pointer(mm
->exe_file
, new_exe_file
);
1020 * get_mm_exe_file - acquire a reference to the mm's executable file
1022 * Returns %NULL if mm has no associated executable file.
1023 * User must release file via fput().
1025 struct file
*get_mm_exe_file(struct mm_struct
*mm
)
1027 struct file
*exe_file
;
1030 exe_file
= rcu_dereference(mm
->exe_file
);
1031 if (exe_file
&& !get_file_rcu(exe_file
))
1036 EXPORT_SYMBOL(get_mm_exe_file
);
1039 * get_task_exe_file - acquire a reference to the task's executable file
1041 * Returns %NULL if task's mm (if any) has no associated executable file or
1042 * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
1043 * User must release file via fput().
1045 struct file
*get_task_exe_file(struct task_struct
*task
)
1047 struct file
*exe_file
= NULL
;
1048 struct mm_struct
*mm
;
1053 if (!(task
->flags
& PF_KTHREAD
))
1054 exe_file
= get_mm_exe_file(mm
);
1059 EXPORT_SYMBOL(get_task_exe_file
);
1062 * get_task_mm - acquire a reference to the task's mm
1064 * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
1065 * this kernel workthread has transiently adopted a user mm with use_mm,
1066 * to do its AIO) is not set and if so returns a reference to it, after
1067 * bumping up the use count. User must release the mm via mmput()
1068 * after use. Typically used by /proc and ptrace.
1070 struct mm_struct
*get_task_mm(struct task_struct
*task
)
1072 struct mm_struct
*mm
;
1077 if (task
->flags
& PF_KTHREAD
)
1085 EXPORT_SYMBOL_GPL(get_task_mm
);
1087 struct mm_struct
*mm_access(struct task_struct
*task
, unsigned int mode
)
1089 struct mm_struct
*mm
;
1092 err
= mutex_lock_killable(&task
->signal
->cred_guard_mutex
);
1094 return ERR_PTR(err
);
1096 mm
= get_task_mm(task
);
1097 if (mm
&& mm
!= current
->mm
&&
1098 !ptrace_may_access(task
, mode
)) {
1100 mm
= ERR_PTR(-EACCES
);
1102 mutex_unlock(&task
->signal
->cred_guard_mutex
);
1107 static void complete_vfork_done(struct task_struct
*tsk
)
1109 struct completion
*vfork
;
1112 vfork
= tsk
->vfork_done
;
1113 if (likely(vfork
)) {
1114 tsk
->vfork_done
= NULL
;
1120 static int wait_for_vfork_done(struct task_struct
*child
,
1121 struct completion
*vfork
)
1125 freezer_do_not_count();
1126 killed
= wait_for_completion_killable(vfork
);
1131 child
->vfork_done
= NULL
;
1135 put_task_struct(child
);
1139 /* Please note the differences between mmput and mm_release.
1140 * mmput is called whenever we stop holding onto a mm_struct,
1141 * error success whatever.
1143 * mm_release is called after a mm_struct has been removed
1144 * from the current process.
1146 * This difference is important for error handling, when we
1147 * only half set up a mm_struct for a new process and need to restore
1148 * the old one. Because we mmput the new mm_struct before
1149 * restoring the old one. . .
1150 * Eric Biederman 10 January 1998
1152 void mm_release(struct task_struct
*tsk
, struct mm_struct
*mm
)
1154 /* Get rid of any futexes when releasing the mm */
1156 if (unlikely(tsk
->robust_list
)) {
1157 exit_robust_list(tsk
);
1158 tsk
->robust_list
= NULL
;
1160 #ifdef CONFIG_COMPAT
1161 if (unlikely(tsk
->compat_robust_list
)) {
1162 compat_exit_robust_list(tsk
);
1163 tsk
->compat_robust_list
= NULL
;
1166 if (unlikely(!list_empty(&tsk
->pi_state_list
)))
1167 exit_pi_state_list(tsk
);
1170 uprobe_free_utask(tsk
);
1172 /* Get rid of any cached register state */
1173 deactivate_mm(tsk
, mm
);
1176 * Signal userspace if we're not exiting with a core dump
1177 * because we want to leave the value intact for debugging
1180 if (tsk
->clear_child_tid
) {
1181 if (!(tsk
->signal
->flags
& SIGNAL_GROUP_COREDUMP
) &&
1182 atomic_read(&mm
->mm_users
) > 1) {
1184 * We don't check the error code - if userspace has
1185 * not set up a proper pointer then tough luck.
1187 put_user(0, tsk
->clear_child_tid
);
1188 sys_futex(tsk
->clear_child_tid
, FUTEX_WAKE
,
1191 tsk
->clear_child_tid
= NULL
;
1195 * All done, finally we can wake up parent and return this mm to him.
1196 * Also kthread_stop() uses this completion for synchronization.
1198 if (tsk
->vfork_done
)
1199 complete_vfork_done(tsk
);
1203 * Allocate a new mm structure and copy contents from the
1204 * mm structure of the passed in task structure.
1206 static struct mm_struct
*dup_mm(struct task_struct
*tsk
)
1208 struct mm_struct
*mm
, *oldmm
= current
->mm
;
1215 memcpy(mm
, oldmm
, sizeof(*mm
));
1217 if (!mm_init(mm
, tsk
, mm
->user_ns
))
1220 err
= dup_mmap(mm
, oldmm
);
1224 mm
->hiwater_rss
= get_mm_rss(mm
);
1225 mm
->hiwater_vm
= mm
->total_vm
;
1227 if (mm
->binfmt
&& !try_module_get(mm
->binfmt
->module
))
1233 /* don't put binfmt in mmput, we haven't got module yet */
1241 static int copy_mm(unsigned long clone_flags
, struct task_struct
*tsk
)
1243 struct mm_struct
*mm
, *oldmm
;
1246 tsk
->min_flt
= tsk
->maj_flt
= 0;
1247 tsk
->nvcsw
= tsk
->nivcsw
= 0;
1248 #ifdef CONFIG_DETECT_HUNG_TASK
1249 tsk
->last_switch_count
= tsk
->nvcsw
+ tsk
->nivcsw
;
1253 tsk
->active_mm
= NULL
;
1256 * Are we cloning a kernel thread?
1258 * We need to steal a active VM for that..
1260 oldmm
= current
->mm
;
1264 /* initialize the new vmacache entries */
1265 vmacache_flush(tsk
);
1267 if (clone_flags
& CLONE_VM
) {
1280 tsk
->active_mm
= mm
;
1287 static int copy_fs(unsigned long clone_flags
, struct task_struct
*tsk
)
1289 struct fs_struct
*fs
= current
->fs
;
1290 if (clone_flags
& CLONE_FS
) {
1291 /* tsk->fs is already what we want */
1292 spin_lock(&fs
->lock
);
1294 spin_unlock(&fs
->lock
);
1298 spin_unlock(&fs
->lock
);
1301 tsk
->fs
= copy_fs_struct(fs
);
1307 static int copy_files(unsigned long clone_flags
, struct task_struct
*tsk
)
1309 struct files_struct
*oldf
, *newf
;
1313 * A background process may not have any files ...
1315 oldf
= current
->files
;
1319 if (clone_flags
& CLONE_FILES
) {
1320 atomic_inc(&oldf
->count
);
1324 newf
= dup_fd(oldf
, &error
);
1334 static int copy_io(unsigned long clone_flags
, struct task_struct
*tsk
)
1337 struct io_context
*ioc
= current
->io_context
;
1338 struct io_context
*new_ioc
;
1343 * Share io context with parent, if CLONE_IO is set
1345 if (clone_flags
& CLONE_IO
) {
1347 tsk
->io_context
= ioc
;
1348 } else if (ioprio_valid(ioc
->ioprio
)) {
1349 new_ioc
= get_task_io_context(tsk
, GFP_KERNEL
, NUMA_NO_NODE
);
1350 if (unlikely(!new_ioc
))
1353 new_ioc
->ioprio
= ioc
->ioprio
;
1354 put_io_context(new_ioc
);
1360 static int copy_sighand(unsigned long clone_flags
, struct task_struct
*tsk
)
1362 struct sighand_struct
*sig
;
1364 if (clone_flags
& CLONE_SIGHAND
) {
1365 atomic_inc(¤t
->sighand
->count
);
1368 sig
= kmem_cache_alloc(sighand_cachep
, GFP_KERNEL
);
1369 rcu_assign_pointer(tsk
->sighand
, sig
);
1373 atomic_set(&sig
->count
, 1);
1374 memcpy(sig
->action
, current
->sighand
->action
, sizeof(sig
->action
));
1378 void __cleanup_sighand(struct sighand_struct
*sighand
)
1380 if (atomic_dec_and_test(&sighand
->count
)) {
1381 signalfd_cleanup(sighand
);
1383 * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
1384 * without an RCU grace period, see __lock_task_sighand().
1386 kmem_cache_free(sighand_cachep
, sighand
);
1390 #ifdef CONFIG_POSIX_TIMERS
1392 * Initialize POSIX timer handling for a thread group.
1394 static void posix_cpu_timers_init_group(struct signal_struct
*sig
)
1396 unsigned long cpu_limit
;
1398 cpu_limit
= READ_ONCE(sig
->rlim
[RLIMIT_CPU
].rlim_cur
);
1399 if (cpu_limit
!= RLIM_INFINITY
) {
1400 sig
->cputime_expires
.prof_exp
= cpu_limit
* NSEC_PER_SEC
;
1401 sig
->cputimer
.running
= true;
1404 /* The timer lists. */
1405 INIT_LIST_HEAD(&sig
->cpu_timers
[0]);
1406 INIT_LIST_HEAD(&sig
->cpu_timers
[1]);
1407 INIT_LIST_HEAD(&sig
->cpu_timers
[2]);
1410 static inline void posix_cpu_timers_init_group(struct signal_struct
*sig
) { }
1413 static int copy_signal(unsigned long clone_flags
, struct task_struct
*tsk
)
1415 struct signal_struct
*sig
;
1417 if (clone_flags
& CLONE_THREAD
)
1420 sig
= kmem_cache_zalloc(signal_cachep
, GFP_KERNEL
);
1425 sig
->nr_threads
= 1;
1426 atomic_set(&sig
->live
, 1);
1427 atomic_set(&sig
->sigcnt
, 1);
1429 /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
1430 sig
->thread_head
= (struct list_head
)LIST_HEAD_INIT(tsk
->thread_node
);
1431 tsk
->thread_node
= (struct list_head
)LIST_HEAD_INIT(sig
->thread_head
);
1433 init_waitqueue_head(&sig
->wait_chldexit
);
1434 sig
->curr_target
= tsk
;
1435 init_sigpending(&sig
->shared_pending
);
1436 seqlock_init(&sig
->stats_lock
);
1437 prev_cputime_init(&sig
->prev_cputime
);
1439 #ifdef CONFIG_POSIX_TIMERS
1440 INIT_LIST_HEAD(&sig
->posix_timers
);
1441 hrtimer_init(&sig
->real_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1442 sig
->real_timer
.function
= it_real_fn
;
1445 task_lock(current
->group_leader
);
1446 memcpy(sig
->rlim
, current
->signal
->rlim
, sizeof sig
->rlim
);
1447 task_unlock(current
->group_leader
);
1449 posix_cpu_timers_init_group(sig
);
1451 tty_audit_fork(sig
);
1452 sched_autogroup_fork(sig
);
1454 sig
->oom_score_adj
= current
->signal
->oom_score_adj
;
1455 sig
->oom_score_adj_min
= current
->signal
->oom_score_adj_min
;
1457 mutex_init(&sig
->cred_guard_mutex
);
1462 static void copy_seccomp(struct task_struct
*p
)
1464 #ifdef CONFIG_SECCOMP
1466 * Must be called with sighand->lock held, which is common to
1467 * all threads in the group. Holding cred_guard_mutex is not
1468 * needed because this new task is not yet running and cannot
1471 assert_spin_locked(¤t
->sighand
->siglock
);
1473 /* Ref-count the new filter user, and assign it. */
1474 get_seccomp_filter(current
);
1475 p
->seccomp
= current
->seccomp
;
1478 * Explicitly enable no_new_privs here in case it got set
1479 * between the task_struct being duplicated and holding the
1480 * sighand lock. The seccomp state and nnp must be in sync.
1482 if (task_no_new_privs(current
))
1483 task_set_no_new_privs(p
);
1486 * If the parent gained a seccomp mode after copying thread
1487 * flags and between before we held the sighand lock, we have
1488 * to manually enable the seccomp thread flag here.
1490 if (p
->seccomp
.mode
!= SECCOMP_MODE_DISABLED
)
1491 set_tsk_thread_flag(p
, TIF_SECCOMP
);
1495 SYSCALL_DEFINE1(set_tid_address
, int __user
*, tidptr
)
1497 current
->clear_child_tid
= tidptr
;
1499 return task_pid_vnr(current
);
1502 static void rt_mutex_init_task(struct task_struct
*p
)
1504 raw_spin_lock_init(&p
->pi_lock
);
1505 #ifdef CONFIG_RT_MUTEXES
1506 p
->pi_waiters
= RB_ROOT_CACHED
;
1507 p
->pi_top_task
= NULL
;
1508 p
->pi_blocked_on
= NULL
;
1512 #ifdef CONFIG_POSIX_TIMERS
1514 * Initialize POSIX timer handling for a single task.
1516 static void posix_cpu_timers_init(struct task_struct
*tsk
)
1518 tsk
->cputime_expires
.prof_exp
= 0;
1519 tsk
->cputime_expires
.virt_exp
= 0;
1520 tsk
->cputime_expires
.sched_exp
= 0;
1521 INIT_LIST_HEAD(&tsk
->cpu_timers
[0]);
1522 INIT_LIST_HEAD(&tsk
->cpu_timers
[1]);
1523 INIT_LIST_HEAD(&tsk
->cpu_timers
[2]);
1526 static inline void posix_cpu_timers_init(struct task_struct
*tsk
) { }
1530 init_task_pid(struct task_struct
*task
, enum pid_type type
, struct pid
*pid
)
1532 task
->pids
[type
].pid
= pid
;
1535 static inline void rcu_copy_process(struct task_struct
*p
)
1537 #ifdef CONFIG_PREEMPT_RCU
1538 p
->rcu_read_lock_nesting
= 0;
1539 p
->rcu_read_unlock_special
.s
= 0;
1540 p
->rcu_blocked_node
= NULL
;
1541 INIT_LIST_HEAD(&p
->rcu_node_entry
);
1542 #endif /* #ifdef CONFIG_PREEMPT_RCU */
1543 #ifdef CONFIG_TASKS_RCU
1544 p
->rcu_tasks_holdout
= false;
1545 INIT_LIST_HEAD(&p
->rcu_tasks_holdout_list
);
1546 p
->rcu_tasks_idle_cpu
= -1;
1547 #endif /* #ifdef CONFIG_TASKS_RCU */
1551 * This creates a new process as a copy of the old one,
1552 * but does not actually start it yet.
1554 * It copies the registers, and all the appropriate
1555 * parts of the process environment (as per the clone
1556 * flags). The actual kick-off is left to the caller.
1558 static __latent_entropy
struct task_struct
*copy_process(
1559 unsigned long clone_flags
,
1560 unsigned long stack_start
,
1561 unsigned long stack_size
,
1562 int __user
*child_tidptr
,
1569 struct task_struct
*p
;
1571 if ((clone_flags
& (CLONE_NEWNS
|CLONE_FS
)) == (CLONE_NEWNS
|CLONE_FS
))
1572 return ERR_PTR(-EINVAL
);
1574 if ((clone_flags
& (CLONE_NEWUSER
|CLONE_FS
)) == (CLONE_NEWUSER
|CLONE_FS
))
1575 return ERR_PTR(-EINVAL
);
1578 * Thread groups must share signals as well, and detached threads
1579 * can only be started up within the thread group.
1581 if ((clone_flags
& CLONE_THREAD
) && !(clone_flags
& CLONE_SIGHAND
))
1582 return ERR_PTR(-EINVAL
);
1585 * Shared signal handlers imply shared VM. By way of the above,
1586 * thread groups also imply shared VM. Blocking this case allows
1587 * for various simplifications in other code.
1589 if ((clone_flags
& CLONE_SIGHAND
) && !(clone_flags
& CLONE_VM
))
1590 return ERR_PTR(-EINVAL
);
1593 * Siblings of global init remain as zombies on exit since they are
1594 * not reaped by their parent (swapper). To solve this and to avoid
1595 * multi-rooted process trees, prevent global and container-inits
1596 * from creating siblings.
1598 if ((clone_flags
& CLONE_PARENT
) &&
1599 current
->signal
->flags
& SIGNAL_UNKILLABLE
)
1600 return ERR_PTR(-EINVAL
);
1603 * If the new process will be in a different pid or user namespace
1604 * do not allow it to share a thread group with the forking task.
1606 if (clone_flags
& CLONE_THREAD
) {
1607 if ((clone_flags
& (CLONE_NEWUSER
| CLONE_NEWPID
)) ||
1608 (task_active_pid_ns(current
) !=
1609 current
->nsproxy
->pid_ns_for_children
))
1610 return ERR_PTR(-EINVAL
);
1614 p
= dup_task_struct(current
, node
);
1619 * This _must_ happen before we call free_task(), i.e. before we jump
1620 * to any of the bad_fork_* labels. This is to avoid freeing
1621 * p->set_child_tid which is (ab)used as a kthread's data pointer for
1622 * kernel threads (PF_KTHREAD).
1624 p
->set_child_tid
= (clone_flags
& CLONE_CHILD_SETTID
) ? child_tidptr
: NULL
;
1626 * Clear TID on mm_release()?
1628 p
->clear_child_tid
= (clone_flags
& CLONE_CHILD_CLEARTID
) ? child_tidptr
: NULL
;
1630 ftrace_graph_init_task(p
);
1632 rt_mutex_init_task(p
);
1634 #ifdef CONFIG_PROVE_LOCKING
1635 DEBUG_LOCKS_WARN_ON(!p
->hardirqs_enabled
);
1636 DEBUG_LOCKS_WARN_ON(!p
->softirqs_enabled
);
1639 if (atomic_read(&p
->real_cred
->user
->processes
) >=
1640 task_rlimit(p
, RLIMIT_NPROC
)) {
1641 if (p
->real_cred
->user
!= INIT_USER
&&
1642 !capable(CAP_SYS_RESOURCE
) && !capable(CAP_SYS_ADMIN
))
1645 current
->flags
&= ~PF_NPROC_EXCEEDED
;
1647 retval
= copy_creds(p
, clone_flags
);
1652 * If multiple threads are within copy_process(), then this check
1653 * triggers too late. This doesn't hurt, the check is only there
1654 * to stop root fork bombs.
1657 if (nr_threads
>= max_threads
)
1658 goto bad_fork_cleanup_count
;
1660 delayacct_tsk_init(p
); /* Must remain after dup_task_struct() */
1661 p
->flags
&= ~(PF_SUPERPRIV
| PF_WQ_WORKER
| PF_IDLE
);
1662 p
->flags
|= PF_FORKNOEXEC
;
1663 INIT_LIST_HEAD(&p
->children
);
1664 INIT_LIST_HEAD(&p
->sibling
);
1665 rcu_copy_process(p
);
1666 p
->vfork_done
= NULL
;
1667 spin_lock_init(&p
->alloc_lock
);
1669 init_sigpending(&p
->pending
);
1671 p
->utime
= p
->stime
= p
->gtime
= 0;
1672 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
1673 p
->utimescaled
= p
->stimescaled
= 0;
1675 prev_cputime_init(&p
->prev_cputime
);
1677 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1678 seqcount_init(&p
->vtime
.seqcount
);
1679 p
->vtime
.starttime
= 0;
1680 p
->vtime
.state
= VTIME_INACTIVE
;
1683 #if defined(SPLIT_RSS_COUNTING)
1684 memset(&p
->rss_stat
, 0, sizeof(p
->rss_stat
));
1687 p
->default_timer_slack_ns
= current
->timer_slack_ns
;
1689 task_io_accounting_init(&p
->ioac
);
1690 acct_clear_integrals(p
);
1692 posix_cpu_timers_init(p
);
1694 p
->start_time
= ktime_get_ns();
1695 p
->real_start_time
= ktime_get_boot_ns();
1696 p
->io_context
= NULL
;
1697 p
->audit_context
= NULL
;
1700 p
->mempolicy
= mpol_dup(p
->mempolicy
);
1701 if (IS_ERR(p
->mempolicy
)) {
1702 retval
= PTR_ERR(p
->mempolicy
);
1703 p
->mempolicy
= NULL
;
1704 goto bad_fork_cleanup_threadgroup_lock
;
1707 #ifdef CONFIG_CPUSETS
1708 p
->cpuset_mem_spread_rotor
= NUMA_NO_NODE
;
1709 p
->cpuset_slab_spread_rotor
= NUMA_NO_NODE
;
1710 seqcount_init(&p
->mems_allowed_seq
);
1712 #ifdef CONFIG_TRACE_IRQFLAGS
1714 p
->hardirqs_enabled
= 0;
1715 p
->hardirq_enable_ip
= 0;
1716 p
->hardirq_enable_event
= 0;
1717 p
->hardirq_disable_ip
= _THIS_IP_
;
1718 p
->hardirq_disable_event
= 0;
1719 p
->softirqs_enabled
= 1;
1720 p
->softirq_enable_ip
= _THIS_IP_
;
1721 p
->softirq_enable_event
= 0;
1722 p
->softirq_disable_ip
= 0;
1723 p
->softirq_disable_event
= 0;
1724 p
->hardirq_context
= 0;
1725 p
->softirq_context
= 0;
1728 p
->pagefault_disabled
= 0;
1730 #ifdef CONFIG_LOCKDEP
1731 p
->lockdep_depth
= 0; /* no locks held yet */
1732 p
->curr_chain_key
= 0;
1733 p
->lockdep_recursion
= 0;
1734 lockdep_init_task(p
);
1737 #ifdef CONFIG_DEBUG_MUTEXES
1738 p
->blocked_on
= NULL
; /* not blocked yet */
1740 #ifdef CONFIG_BCACHE
1741 p
->sequential_io
= 0;
1742 p
->sequential_io_avg
= 0;
1745 /* Perform scheduler related setup. Assign this task to a CPU. */
1746 retval
= sched_fork(clone_flags
, p
);
1748 goto bad_fork_cleanup_policy
;
1750 retval
= perf_event_init_task(p
);
1752 goto bad_fork_cleanup_policy
;
1753 retval
= audit_alloc(p
);
1755 goto bad_fork_cleanup_perf
;
1756 /* copy all the process information */
1758 retval
= security_task_alloc(p
, clone_flags
);
1760 goto bad_fork_cleanup_audit
;
1761 retval
= copy_semundo(clone_flags
, p
);
1763 goto bad_fork_cleanup_security
;
1764 retval
= copy_files(clone_flags
, p
);
1766 goto bad_fork_cleanup_semundo
;
1767 retval
= copy_fs(clone_flags
, p
);
1769 goto bad_fork_cleanup_files
;
1770 retval
= copy_sighand(clone_flags
, p
);
1772 goto bad_fork_cleanup_fs
;
1773 retval
= copy_signal(clone_flags
, p
);
1775 goto bad_fork_cleanup_sighand
;
1776 retval
= copy_mm(clone_flags
, p
);
1778 goto bad_fork_cleanup_signal
;
1779 retval
= copy_namespaces(clone_flags
, p
);
1781 goto bad_fork_cleanup_mm
;
1782 retval
= copy_io(clone_flags
, p
);
1784 goto bad_fork_cleanup_namespaces
;
1785 retval
= copy_thread_tls(clone_flags
, stack_start
, stack_size
, p
, tls
);
1787 goto bad_fork_cleanup_io
;
1789 if (pid
!= &init_struct_pid
) {
1790 pid
= alloc_pid(p
->nsproxy
->pid_ns_for_children
);
1792 retval
= PTR_ERR(pid
);
1793 goto bad_fork_cleanup_thread
;
1801 p
->robust_list
= NULL
;
1802 #ifdef CONFIG_COMPAT
1803 p
->compat_robust_list
= NULL
;
1805 INIT_LIST_HEAD(&p
->pi_state_list
);
1806 p
->pi_state_cache
= NULL
;
1809 * sigaltstack should be cleared when sharing the same VM
1811 if ((clone_flags
& (CLONE_VM
|CLONE_VFORK
)) == CLONE_VM
)
1815 * Syscall tracing and stepping should be turned off in the
1816 * child regardless of CLONE_PTRACE.
1818 user_disable_single_step(p
);
1819 clear_tsk_thread_flag(p
, TIF_SYSCALL_TRACE
);
1820 #ifdef TIF_SYSCALL_EMU
1821 clear_tsk_thread_flag(p
, TIF_SYSCALL_EMU
);
1823 clear_all_latency_tracing(p
);
1825 /* ok, now we should be set up.. */
1826 p
->pid
= pid_nr(pid
);
1827 if (clone_flags
& CLONE_THREAD
) {
1828 p
->exit_signal
= -1;
1829 p
->group_leader
= current
->group_leader
;
1830 p
->tgid
= current
->tgid
;
1832 if (clone_flags
& CLONE_PARENT
)
1833 p
->exit_signal
= current
->group_leader
->exit_signal
;
1835 p
->exit_signal
= (clone_flags
& CSIGNAL
);
1836 p
->group_leader
= p
;
1841 p
->nr_dirtied_pause
= 128 >> (PAGE_SHIFT
- 10);
1842 p
->dirty_paused_when
= 0;
1844 p
->pdeath_signal
= 0;
1845 INIT_LIST_HEAD(&p
->thread_group
);
1846 p
->task_works
= NULL
;
1848 cgroup_threadgroup_change_begin(current
);
1850 * Ensure that the cgroup subsystem policies allow the new process to be
1851 * forked. It should be noted the the new process's css_set can be changed
1852 * between here and cgroup_post_fork() if an organisation operation is in
1855 retval
= cgroup_can_fork(p
);
1857 goto bad_fork_free_pid
;
1860 * Make it visible to the rest of the system, but dont wake it up yet.
1861 * Need tasklist lock for parent etc handling!
1863 write_lock_irq(&tasklist_lock
);
1865 /* CLONE_PARENT re-uses the old parent */
1866 if (clone_flags
& (CLONE_PARENT
|CLONE_THREAD
)) {
1867 p
->real_parent
= current
->real_parent
;
1868 p
->parent_exec_id
= current
->parent_exec_id
;
1870 p
->real_parent
= current
;
1871 p
->parent_exec_id
= current
->self_exec_id
;
1874 klp_copy_process(p
);
1876 spin_lock(¤t
->sighand
->siglock
);
1879 * Copy seccomp details explicitly here, in case they were changed
1880 * before holding sighand lock.
1885 * Process group and session signals need to be delivered to just the
1886 * parent before the fork or both the parent and the child after the
1887 * fork. Restart if a signal comes in before we add the new process to
1888 * it's process group.
1889 * A fatal signal pending means that current will exit, so the new
1890 * thread can't slip out of an OOM kill (or normal SIGKILL).
1892 recalc_sigpending();
1893 if (signal_pending(current
)) {
1894 retval
= -ERESTARTNOINTR
;
1895 goto bad_fork_cancel_cgroup
;
1897 if (unlikely(!(ns_of_pid(pid
)->pid_allocated
& PIDNS_ADDING
))) {
1899 goto bad_fork_cancel_cgroup
;
1902 if (likely(p
->pid
)) {
1903 ptrace_init_task(p
, (clone_flags
& CLONE_PTRACE
) || trace
);
1905 init_task_pid(p
, PIDTYPE_PID
, pid
);
1906 if (thread_group_leader(p
)) {
1907 init_task_pid(p
, PIDTYPE_PGID
, task_pgrp(current
));
1908 init_task_pid(p
, PIDTYPE_SID
, task_session(current
));
1910 if (is_child_reaper(pid
)) {
1911 ns_of_pid(pid
)->child_reaper
= p
;
1912 p
->signal
->flags
|= SIGNAL_UNKILLABLE
;
1915 p
->signal
->leader_pid
= pid
;
1916 p
->signal
->tty
= tty_kref_get(current
->signal
->tty
);
1918 * Inherit has_child_subreaper flag under the same
1919 * tasklist_lock with adding child to the process tree
1920 * for propagate_has_child_subreaper optimization.
1922 p
->signal
->has_child_subreaper
= p
->real_parent
->signal
->has_child_subreaper
||
1923 p
->real_parent
->signal
->is_child_subreaper
;
1924 list_add_tail(&p
->sibling
, &p
->real_parent
->children
);
1925 list_add_tail_rcu(&p
->tasks
, &init_task
.tasks
);
1926 attach_pid(p
, PIDTYPE_PGID
);
1927 attach_pid(p
, PIDTYPE_SID
);
1928 __this_cpu_inc(process_counts
);
1930 current
->signal
->nr_threads
++;
1931 atomic_inc(¤t
->signal
->live
);
1932 atomic_inc(¤t
->signal
->sigcnt
);
1933 list_add_tail_rcu(&p
->thread_group
,
1934 &p
->group_leader
->thread_group
);
1935 list_add_tail_rcu(&p
->thread_node
,
1936 &p
->signal
->thread_head
);
1938 attach_pid(p
, PIDTYPE_PID
);
1943 spin_unlock(¤t
->sighand
->siglock
);
1944 syscall_tracepoint_update(p
);
1945 write_unlock_irq(&tasklist_lock
);
1947 proc_fork_connector(p
);
1948 cgroup_post_fork(p
);
1949 cgroup_threadgroup_change_end(current
);
1952 trace_task_newtask(p
, clone_flags
);
1953 uprobe_copy_process(p
, clone_flags
);
1957 bad_fork_cancel_cgroup
:
1958 spin_unlock(¤t
->sighand
->siglock
);
1959 write_unlock_irq(&tasklist_lock
);
1960 cgroup_cancel_fork(p
);
1962 cgroup_threadgroup_change_end(current
);
1963 if (pid
!= &init_struct_pid
)
1965 bad_fork_cleanup_thread
:
1967 bad_fork_cleanup_io
:
1970 bad_fork_cleanup_namespaces
:
1971 exit_task_namespaces(p
);
1972 bad_fork_cleanup_mm
:
1975 bad_fork_cleanup_signal
:
1976 if (!(clone_flags
& CLONE_THREAD
))
1977 free_signal_struct(p
->signal
);
1978 bad_fork_cleanup_sighand
:
1979 __cleanup_sighand(p
->sighand
);
1980 bad_fork_cleanup_fs
:
1981 exit_fs(p
); /* blocking */
1982 bad_fork_cleanup_files
:
1983 exit_files(p
); /* blocking */
1984 bad_fork_cleanup_semundo
:
1986 bad_fork_cleanup_security
:
1987 security_task_free(p
);
1988 bad_fork_cleanup_audit
:
1990 bad_fork_cleanup_perf
:
1991 perf_event_free_task(p
);
1992 bad_fork_cleanup_policy
:
1993 lockdep_free_task(p
);
1995 mpol_put(p
->mempolicy
);
1996 bad_fork_cleanup_threadgroup_lock
:
1998 delayacct_tsk_free(p
);
1999 bad_fork_cleanup_count
:
2000 atomic_dec(&p
->cred
->user
->processes
);
2003 p
->state
= TASK_DEAD
;
2007 return ERR_PTR(retval
);
2010 static inline void init_idle_pids(struct pid_link
*links
)
2014 for (type
= PIDTYPE_PID
; type
< PIDTYPE_MAX
; ++type
) {
2015 INIT_HLIST_NODE(&links
[type
].node
); /* not really needed */
2016 links
[type
].pid
= &init_struct_pid
;
2020 struct task_struct
*fork_idle(int cpu
)
2022 struct task_struct
*task
;
2023 task
= copy_process(CLONE_VM
, 0, 0, NULL
, &init_struct_pid
, 0, 0,
2025 if (!IS_ERR(task
)) {
2026 init_idle_pids(task
->pids
);
2027 init_idle(task
, cpu
);
2034 * Ok, this is the main fork-routine.
2036 * It copies the process, and if successful kick-starts
2037 * it and waits for it to finish using the VM if required.
2039 long _do_fork(unsigned long clone_flags
,
2040 unsigned long stack_start
,
2041 unsigned long stack_size
,
2042 int __user
*parent_tidptr
,
2043 int __user
*child_tidptr
,
2046 struct task_struct
*p
;
2051 * Determine whether and which event to report to ptracer. When
2052 * called from kernel_thread or CLONE_UNTRACED is explicitly
2053 * requested, no event is reported; otherwise, report if the event
2054 * for the type of forking is enabled.
2056 if (!(clone_flags
& CLONE_UNTRACED
)) {
2057 if (clone_flags
& CLONE_VFORK
)
2058 trace
= PTRACE_EVENT_VFORK
;
2059 else if ((clone_flags
& CSIGNAL
) != SIGCHLD
)
2060 trace
= PTRACE_EVENT_CLONE
;
2062 trace
= PTRACE_EVENT_FORK
;
2064 if (likely(!ptrace_event_enabled(current
, trace
)))
2068 p
= copy_process(clone_flags
, stack_start
, stack_size
,
2069 child_tidptr
, NULL
, trace
, tls
, NUMA_NO_NODE
);
2070 add_latent_entropy();
2072 * Do this prior waking up the new thread - the thread pointer
2073 * might get invalid after that point, if the thread exits quickly.
2076 struct completion vfork
;
2079 trace_sched_process_fork(current
, p
);
2081 pid
= get_task_pid(p
, PIDTYPE_PID
);
2084 if (clone_flags
& CLONE_PARENT_SETTID
)
2085 put_user(nr
, parent_tidptr
);
2087 if (clone_flags
& CLONE_VFORK
) {
2088 p
->vfork_done
= &vfork
;
2089 init_completion(&vfork
);
2093 wake_up_new_task(p
);
2095 /* forking complete and child started to run, tell ptracer */
2096 if (unlikely(trace
))
2097 ptrace_event_pid(trace
, pid
);
2099 if (clone_flags
& CLONE_VFORK
) {
2100 if (!wait_for_vfork_done(p
, &vfork
))
2101 ptrace_event_pid(PTRACE_EVENT_VFORK_DONE
, pid
);
2111 #ifndef CONFIG_HAVE_COPY_THREAD_TLS
2112 /* For compatibility with architectures that call do_fork directly rather than
2113 * using the syscall entry points below. */
2114 long do_fork(unsigned long clone_flags
,
2115 unsigned long stack_start
,
2116 unsigned long stack_size
,
2117 int __user
*parent_tidptr
,
2118 int __user
*child_tidptr
)
2120 return _do_fork(clone_flags
, stack_start
, stack_size
,
2121 parent_tidptr
, child_tidptr
, 0);
2126 * Create a kernel thread.
2128 pid_t
kernel_thread(int (*fn
)(void *), void *arg
, unsigned long flags
)
2130 return _do_fork(flags
|CLONE_VM
|CLONE_UNTRACED
, (unsigned long)fn
,
2131 (unsigned long)arg
, NULL
, NULL
, 0);
2134 #ifdef __ARCH_WANT_SYS_FORK
2135 SYSCALL_DEFINE0(fork
)
2138 return _do_fork(SIGCHLD
, 0, 0, NULL
, NULL
, 0);
2140 /* can not support in nommu mode */
2146 #ifdef __ARCH_WANT_SYS_VFORK
2147 SYSCALL_DEFINE0(vfork
)
2149 return _do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, 0,
2154 #ifdef __ARCH_WANT_SYS_CLONE
2155 #ifdef CONFIG_CLONE_BACKWARDS
2156 SYSCALL_DEFINE5(clone
, unsigned long, clone_flags
, unsigned long, newsp
,
2157 int __user
*, parent_tidptr
,
2159 int __user
*, child_tidptr
)
2160 #elif defined(CONFIG_CLONE_BACKWARDS2)
2161 SYSCALL_DEFINE5(clone
, unsigned long, newsp
, unsigned long, clone_flags
,
2162 int __user
*, parent_tidptr
,
2163 int __user
*, child_tidptr
,
2165 #elif defined(CONFIG_CLONE_BACKWARDS3)
2166 SYSCALL_DEFINE6(clone
, unsigned long, clone_flags
, unsigned long, newsp
,
2168 int __user
*, parent_tidptr
,
2169 int __user
*, child_tidptr
,
2172 SYSCALL_DEFINE5(clone
, unsigned long, clone_flags
, unsigned long, newsp
,
2173 int __user
*, parent_tidptr
,
2174 int __user
*, child_tidptr
,
2178 return _do_fork(clone_flags
, newsp
, 0, parent_tidptr
, child_tidptr
, tls
);
2182 void walk_process_tree(struct task_struct
*top
, proc_visitor visitor
, void *data
)
2184 struct task_struct
*leader
, *parent
, *child
;
2187 read_lock(&tasklist_lock
);
2188 leader
= top
= top
->group_leader
;
2190 for_each_thread(leader
, parent
) {
2191 list_for_each_entry(child
, &parent
->children
, sibling
) {
2192 res
= visitor(child
, data
);
2204 if (leader
!= top
) {
2206 parent
= child
->real_parent
;
2207 leader
= parent
->group_leader
;
2211 read_unlock(&tasklist_lock
);
2214 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
2215 #define ARCH_MIN_MMSTRUCT_ALIGN 0
2218 static void sighand_ctor(void *data
)
2220 struct sighand_struct
*sighand
= data
;
2222 spin_lock_init(&sighand
->siglock
);
2223 init_waitqueue_head(&sighand
->signalfd_wqh
);
2226 void __init
proc_caches_init(void)
2228 sighand_cachep
= kmem_cache_create("sighand_cache",
2229 sizeof(struct sighand_struct
), 0,
2230 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_TYPESAFE_BY_RCU
|
2231 SLAB_ACCOUNT
, sighand_ctor
);
2232 signal_cachep
= kmem_cache_create("signal_cache",
2233 sizeof(struct signal_struct
), 0,
2234 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_ACCOUNT
,
2236 files_cachep
= kmem_cache_create("files_cache",
2237 sizeof(struct files_struct
), 0,
2238 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_ACCOUNT
,
2240 fs_cachep
= kmem_cache_create("fs_cache",
2241 sizeof(struct fs_struct
), 0,
2242 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_ACCOUNT
,
2245 * FIXME! The "sizeof(struct mm_struct)" currently includes the
2246 * whole struct cpumask for the OFFSTACK case. We could change
2247 * this to *only* allocate as much of it as required by the
2248 * maximum number of CPU's we can ever have. The cpumask_allocation
2249 * is at the end of the structure, exactly for that reason.
2251 mm_cachep
= kmem_cache_create("mm_struct",
2252 sizeof(struct mm_struct
), ARCH_MIN_MMSTRUCT_ALIGN
,
2253 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
|SLAB_ACCOUNT
,
2255 vm_area_cachep
= KMEM_CACHE(vm_area_struct
, SLAB_PANIC
|SLAB_ACCOUNT
);
2257 nsproxy_cache_init();
2261 * Check constraints on flags passed to the unshare system call.
2263 static int check_unshare_flags(unsigned long unshare_flags
)
2265 if (unshare_flags
& ~(CLONE_THREAD
|CLONE_FS
|CLONE_NEWNS
|CLONE_SIGHAND
|
2266 CLONE_VM
|CLONE_FILES
|CLONE_SYSVSEM
|
2267 CLONE_NEWUTS
|CLONE_NEWIPC
|CLONE_NEWNET
|
2268 CLONE_NEWUSER
|CLONE_NEWPID
|CLONE_NEWCGROUP
))
2271 * Not implemented, but pretend it works if there is nothing
2272 * to unshare. Note that unsharing the address space or the
2273 * signal handlers also need to unshare the signal queues (aka
2276 if (unshare_flags
& (CLONE_THREAD
| CLONE_SIGHAND
| CLONE_VM
)) {
2277 if (!thread_group_empty(current
))
2280 if (unshare_flags
& (CLONE_SIGHAND
| CLONE_VM
)) {
2281 if (atomic_read(¤t
->sighand
->count
) > 1)
2284 if (unshare_flags
& CLONE_VM
) {
2285 if (!current_is_single_threaded())
2293 * Unshare the filesystem structure if it is being shared
2295 static int unshare_fs(unsigned long unshare_flags
, struct fs_struct
**new_fsp
)
2297 struct fs_struct
*fs
= current
->fs
;
2299 if (!(unshare_flags
& CLONE_FS
) || !fs
)
2302 /* don't need lock here; in the worst case we'll do useless copy */
2306 *new_fsp
= copy_fs_struct(fs
);
2314 * Unshare file descriptor table if it is being shared
2316 static int unshare_fd(unsigned long unshare_flags
, struct files_struct
**new_fdp
)
2318 struct files_struct
*fd
= current
->files
;
2321 if ((unshare_flags
& CLONE_FILES
) &&
2322 (fd
&& atomic_read(&fd
->count
) > 1)) {
2323 *new_fdp
= dup_fd(fd
, &error
);
2332 * unshare allows a process to 'unshare' part of the process
2333 * context which was originally shared using clone. copy_*
2334 * functions used by do_fork() cannot be used here directly
2335 * because they modify an inactive task_struct that is being
2336 * constructed. Here we are modifying the current, active,
2339 SYSCALL_DEFINE1(unshare
, unsigned long, unshare_flags
)
2341 struct fs_struct
*fs
, *new_fs
= NULL
;
2342 struct files_struct
*fd
, *new_fd
= NULL
;
2343 struct cred
*new_cred
= NULL
;
2344 struct nsproxy
*new_nsproxy
= NULL
;
2349 * If unsharing a user namespace must also unshare the thread group
2350 * and unshare the filesystem root and working directories.
2352 if (unshare_flags
& CLONE_NEWUSER
)
2353 unshare_flags
|= CLONE_THREAD
| CLONE_FS
;
2355 * If unsharing vm, must also unshare signal handlers.
2357 if (unshare_flags
& CLONE_VM
)
2358 unshare_flags
|= CLONE_SIGHAND
;
2360 * If unsharing a signal handlers, must also unshare the signal queues.
2362 if (unshare_flags
& CLONE_SIGHAND
)
2363 unshare_flags
|= CLONE_THREAD
;
2365 * If unsharing namespace, must also unshare filesystem information.
2367 if (unshare_flags
& CLONE_NEWNS
)
2368 unshare_flags
|= CLONE_FS
;
2370 err
= check_unshare_flags(unshare_flags
);
2372 goto bad_unshare_out
;
2374 * CLONE_NEWIPC must also detach from the undolist: after switching
2375 * to a new ipc namespace, the semaphore arrays from the old
2376 * namespace are unreachable.
2378 if (unshare_flags
& (CLONE_NEWIPC
|CLONE_SYSVSEM
))
2380 err
= unshare_fs(unshare_flags
, &new_fs
);
2382 goto bad_unshare_out
;
2383 err
= unshare_fd(unshare_flags
, &new_fd
);
2385 goto bad_unshare_cleanup_fs
;
2386 err
= unshare_userns(unshare_flags
, &new_cred
);
2388 goto bad_unshare_cleanup_fd
;
2389 err
= unshare_nsproxy_namespaces(unshare_flags
, &new_nsproxy
,
2392 goto bad_unshare_cleanup_cred
;
2394 if (new_fs
|| new_fd
|| do_sysvsem
|| new_cred
|| new_nsproxy
) {
2397 * CLONE_SYSVSEM is equivalent to sys_exit().
2401 if (unshare_flags
& CLONE_NEWIPC
) {
2402 /* Orphan segments in old ns (see sem above). */
2404 shm_init_task(current
);
2408 switch_task_namespaces(current
, new_nsproxy
);
2414 spin_lock(&fs
->lock
);
2415 current
->fs
= new_fs
;
2420 spin_unlock(&fs
->lock
);
2424 fd
= current
->files
;
2425 current
->files
= new_fd
;
2429 task_unlock(current
);
2432 /* Install the new user namespace */
2433 commit_creds(new_cred
);
2438 perf_event_namespaces(current
);
2440 bad_unshare_cleanup_cred
:
2443 bad_unshare_cleanup_fd
:
2445 put_files_struct(new_fd
);
2447 bad_unshare_cleanup_fs
:
2449 free_fs_struct(new_fs
);
2456 * Helper to unshare the files of the current task.
2457 * We don't want to expose copy_files internals to
2458 * the exec layer of the kernel.
2461 int unshare_files(struct files_struct
**displaced
)
2463 struct task_struct
*task
= current
;
2464 struct files_struct
*copy
= NULL
;
2467 error
= unshare_fd(CLONE_FILES
, ©
);
2468 if (error
|| !copy
) {
2472 *displaced
= task
->files
;
2479 int sysctl_max_threads(struct ctl_table
*table
, int write
,
2480 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
2484 int threads
= max_threads
;
2485 int min
= MIN_THREADS
;
2486 int max
= MAX_THREADS
;
2493 ret
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
2497 set_max_threads(threads
);