1
2
3
4
5
6
7
8
9
10
11
12
13
14#include <linux/slab.h>
15#include <linux/init.h>
16#include <linux/unistd.h>
17#include <linux/module.h>
18#include <linux/vmalloc.h>
19#include <linux/completion.h>
20#include <linux/personality.h>
21#include <linux/mempolicy.h>
22#include <linux/sem.h>
23#include <linux/file.h>
24#include <linux/fdtable.h>
25#include <linux/iocontext.h>
26#include <linux/key.h>
27#include <linux/binfmts.h>
28#include <linux/mman.h>
29#include <linux/mmu_notifier.h>
30#include <linux/fs.h>
31#include <linux/mm.h>
32#include <linux/vmacache.h>
33#include <linux/nsproxy.h>
34#include <linux/capability.h>
35#include <linux/cpu.h>
36#include <linux/cgroup.h>
37#include <linux/security.h>
38#include <linux/hugetlb.h>
39#include <linux/seccomp.h>
40#include <linux/swap.h>
41#include <linux/syscalls.h>
42#include <linux/jiffies.h>
43#include <linux/futex.h>
44#include <linux/compat.h>
45#include <linux/kthread.h>
46#include <linux/task_io_accounting_ops.h>
47#include <linux/rcupdate.h>
48#include <linux/ptrace.h>
49#include <linux/mount.h>
50#include <linux/audit.h>
51#include <linux/memcontrol.h>
52#include <linux/ftrace.h>
53#include <linux/proc_fs.h>
54#include <linux/profile.h>
55#include <linux/rmap.h>
56#include <linux/ksm.h>
57#include <linux/acct.h>
58#include <linux/tsacct_kern.h>
59#include <linux/cn_proc.h>
60#include <linux/freezer.h>
61#include <linux/delayacct.h>
62#include <linux/taskstats_kern.h>
63#include <linux/random.h>
64#include <linux/tty.h>
65#include <linux/blkdev.h>
66#include <linux/fs_struct.h>
67#include <linux/magic.h>
68#include <linux/perf_event.h>
69#include <linux/posix-timers.h>
70#include <linux/user-return-notifier.h>
71#include <linux/oom.h>
72#include <linux/khugepaged.h>
73#include <linux/signalfd.h>
74#include <linux/uprobes.h>
75#include <linux/aio.h>
76#include <linux/compiler.h>
77#include <linux/sysctl.h>
78#include <linux/kcov.h>
79
80#include <asm/pgtable.h>
81#include <asm/pgalloc.h>
82#include <asm/uaccess.h>
83#include <asm/mmu_context.h>
84#include <asm/cacheflush.h>
85#include <asm/tlbflush.h>
86
87#include <trace/events/sched.h>
88
89#define CREATE_TRACE_POINTS
90#include <trace/events/task.h>
91
92
93
94
95#define MIN_THREADS 20
96
97
98
99
100#define MAX_THREADS FUTEX_TID_MASK
101
102
103
104
105unsigned long total_forks;
106int nr_threads;
107
108int max_threads;
109
110DEFINE_PER_CPU(unsigned long, process_counts) = 0;
111
112__cacheline_aligned DEFINE_RWLOCK(tasklist_lock);
113
114#ifdef CONFIG_PROVE_RCU
115int lockdep_tasklist_lock_is_held(void)
116{
117 return lockdep_is_held(&tasklist_lock);
118}
119EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
120#endif
121
122int nr_processes(void)
123{
124 int cpu;
125 int total = 0;
126
127 for_each_possible_cpu(cpu)
128 total += per_cpu(process_counts, cpu);
129
130 return total;
131}
132
133void __weak arch_release_task_struct(struct task_struct *tsk)
134{
135}
136
137#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
138static struct kmem_cache *task_struct_cachep;
139
140static inline struct task_struct *alloc_task_struct_node(int node)
141{
142 return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
143}
144
145static inline void free_task_struct(struct task_struct *tsk)
146{
147 kmem_cache_free(task_struct_cachep, tsk);
148}
149#endif
150
151void __weak arch_release_thread_info(struct thread_info *ti)
152{
153}
154
155#ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR
156
157
158
159
160
161# if THREAD_SIZE >= PAGE_SIZE
162static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
163 int node)
164{
165 struct page *page = alloc_kmem_pages_node(node, THREADINFO_GFP,
166 THREAD_SIZE_ORDER);
167
168 if (page)
169 memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,
170 1 << THREAD_SIZE_ORDER);
171
172 return page ? page_address(page) : NULL;
173}
174
175static inline void free_thread_info(struct thread_info *ti)
176{
177 struct page *page = virt_to_page(ti);
178
179 memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,
180 -(1 << THREAD_SIZE_ORDER));
181 __free_kmem_pages(page, THREAD_SIZE_ORDER);
182}
183# else
184static struct kmem_cache *thread_info_cache;
185
186static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
187 int node)
188{
189 return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node);
190}
191
192static void free_thread_info(struct thread_info *ti)
193{
194 kmem_cache_free(thread_info_cache, ti);
195}
196
197void thread_info_cache_init(void)
198{
199 thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
200 THREAD_SIZE, 0, NULL);
201 BUG_ON(thread_info_cache == NULL);
202}
203# endif
204#endif
205
206
207static struct kmem_cache *signal_cachep;
208
209
210struct kmem_cache *sighand_cachep;
211
212
213struct kmem_cache *files_cachep;
214
215
216struct kmem_cache *fs_cachep;
217
218
219struct kmem_cache *vm_area_cachep;
220
221
222static struct kmem_cache *mm_cachep;
223
224static void account_kernel_stack(struct thread_info *ti, int account)
225{
226 struct zone *zone = page_zone(virt_to_page(ti));
227
228 mod_zone_page_state(zone, NR_KERNEL_STACK, account);
229}
230
231void free_task(struct task_struct *tsk)
232{
233 account_kernel_stack(tsk->stack, -1);
234 arch_release_thread_info(tsk->stack);
235 free_thread_info(tsk->stack);
236 rt_mutex_debug_task_free(tsk);
237 ftrace_graph_exit_task(tsk);
238 put_seccomp_filter(tsk);
239 arch_release_task_struct(tsk);
240 free_task_struct(tsk);
241}
242EXPORT_SYMBOL(free_task);
243
244static inline void free_signal_struct(struct signal_struct *sig)
245{
246 taskstats_tgid_free(sig);
247 sched_autogroup_exit(sig);
248 kmem_cache_free(signal_cachep, sig);
249}
250
251static inline void put_signal_struct(struct signal_struct *sig)
252{
253 if (atomic_dec_and_test(&sig->sigcnt))
254 free_signal_struct(sig);
255}
256
257void __put_task_struct(struct task_struct *tsk)
258{
259 WARN_ON(!tsk->exit_state);
260 WARN_ON(atomic_read(&tsk->usage));
261 WARN_ON(tsk == current);
262
263 cgroup_free(tsk);
264 task_numa_free(tsk);
265 security_task_free(tsk);
266 exit_creds(tsk);
267 delayacct_tsk_free(tsk);
268 put_signal_struct(tsk->signal);
269
270 if (!profile_handoff_task(tsk))
271 free_task(tsk);
272}
273EXPORT_SYMBOL_GPL(__put_task_struct);
274
275void __init __weak arch_task_cache_init(void) { }
276
277
278
279
280static void set_max_threads(unsigned int max_threads_suggested)
281{
282 u64 threads;
283
284
285
286
287
288 if (fls64(totalram_pages) + fls64(PAGE_SIZE) > 64)
289 threads = MAX_THREADS;
290 else
291 threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE,
292 (u64) THREAD_SIZE * 8UL);
293
294 if (threads > max_threads_suggested)
295 threads = max_threads_suggested;
296
297 max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
298}
299
300#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
301
302int arch_task_struct_size __read_mostly;
303#endif
304
305void __init fork_init(void)
306{
307#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
308#ifndef ARCH_MIN_TASKALIGN
309#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
310#endif
311
312 task_struct_cachep = kmem_cache_create("task_struct",
313 arch_task_struct_size, ARCH_MIN_TASKALIGN,
314 SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, NULL);
315#endif
316
317
318 arch_task_cache_init();
319
320 set_max_threads(MAX_THREADS);
321
322 init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
323 init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
324 init_task.signal->rlim[RLIMIT_SIGPENDING] =
325 init_task.signal->rlim[RLIMIT_NPROC];
326}
327
328int __weak arch_dup_task_struct(struct task_struct *dst,
329 struct task_struct *src)
330{
331 *dst = *src;
332 return 0;
333}
334
335void set_task_stack_end_magic(struct task_struct *tsk)
336{
337 unsigned long *stackend;
338
339 stackend = end_of_stack(tsk);
340 *stackend = STACK_END_MAGIC;
341}
342
343static struct task_struct *dup_task_struct(struct task_struct *orig)
344{
345 struct task_struct *tsk;
346 struct thread_info *ti;
347 int node = tsk_fork_get_node(orig);
348 int err;
349
350 tsk = alloc_task_struct_node(node);
351 if (!tsk)
352 return NULL;
353
354 ti = alloc_thread_info_node(tsk, node);
355 if (!ti)
356 goto free_tsk;
357
358 err = arch_dup_task_struct(tsk, orig);
359 if (err)
360 goto free_ti;
361
362 tsk->stack = ti;
363#ifdef CONFIG_SECCOMP
364
365
366
367
368
369
370 tsk->seccomp.filter = NULL;
371#endif
372
373 setup_thread_stack(tsk, orig);
374 clear_user_return_notifier(tsk);
375 clear_tsk_need_resched(tsk);
376 set_task_stack_end_magic(tsk);
377
378#ifdef CONFIG_CC_STACKPROTECTOR
379 tsk->stack_canary = get_random_int();
380#endif
381
382
383
384
385
386 atomic_set(&tsk->usage, 2);
387#ifdef CONFIG_BLK_DEV_IO_TRACE
388 tsk->btrace_seq = 0;
389#endif
390 tsk->splice_pipe = NULL;
391 tsk->task_frag.page = NULL;
392 tsk->wake_q.next = NULL;
393
394 account_kernel_stack(ti, 1);
395
396 kcov_task_init(tsk);
397
398 return tsk;
399
400free_ti:
401 free_thread_info(ti);
402free_tsk:
403 free_task_struct(tsk);
404 return NULL;
405}
406
407#ifdef CONFIG_MMU
408static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
409{
410 struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
411 struct rb_node **rb_link, *rb_parent;
412 int retval;
413 unsigned long charge;
414
415 uprobe_start_dup_mmap();
416 down_write(&oldmm->mmap_sem);
417 flush_cache_dup_mm(oldmm);
418 uprobe_dup_mmap(oldmm, mm);
419
420
421
422 down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
423
424
425 RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
426
427 mm->total_vm = oldmm->total_vm;
428 mm->data_vm = oldmm->data_vm;
429 mm->exec_vm = oldmm->exec_vm;
430 mm->stack_vm = oldmm->stack_vm;
431
432 rb_link = &mm->mm_rb.rb_node;
433 rb_parent = NULL;
434 pprev = &mm->mmap;
435 retval = ksm_fork(mm, oldmm);
436 if (retval)
437 goto out;
438 retval = khugepaged_fork(mm, oldmm);
439 if (retval)
440 goto out;
441
442 prev = NULL;
443 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
444 struct file *file;
445
446 if (mpnt->vm_flags & VM_DONTCOPY) {
447 vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
448 continue;
449 }
450 charge = 0;
451 if (mpnt->vm_flags & VM_ACCOUNT) {
452 unsigned long len = vma_pages(mpnt);
453
454 if (security_vm_enough_memory_mm(oldmm, len))
455 goto fail_nomem;
456 charge = len;
457 }
458 tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
459 if (!tmp)
460 goto fail_nomem;
461 *tmp = *mpnt;
462 INIT_LIST_HEAD(&tmp->anon_vma_chain);
463 retval = vma_dup_policy(mpnt, tmp);
464 if (retval)
465 goto fail_nomem_policy;
466 tmp->vm_mm = mm;
467 if (anon_vma_fork(tmp, mpnt))
468 goto fail_nomem_anon_vma_fork;
469 tmp->vm_flags &=
470 ~(VM_LOCKED|VM_LOCKONFAULT|VM_UFFD_MISSING|VM_UFFD_WP);
471 tmp->vm_next = tmp->vm_prev = NULL;
472 tmp->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
473 file = tmp->vm_file;
474 if (file) {
475 struct inode *inode = file_inode(file);
476 struct address_space *mapping = file->f_mapping;
477
478 get_file(file);
479 if (tmp->vm_flags & VM_DENYWRITE)
480 atomic_dec(&inode->i_writecount);
481 i_mmap_lock_write(mapping);
482 if (tmp->vm_flags & VM_SHARED)
483 atomic_inc(&mapping->i_mmap_writable);
484 flush_dcache_mmap_lock(mapping);
485
486 vma_interval_tree_insert_after(tmp, mpnt,
487 &mapping->i_mmap);
488 flush_dcache_mmap_unlock(mapping);
489 i_mmap_unlock_write(mapping);
490 }
491
492
493
494
495
496
497 if (is_vm_hugetlb_page(tmp))
498 reset_vma_resv_huge_pages(tmp);
499
500
501
502
503 *pprev = tmp;
504 pprev = &tmp->vm_next;
505 tmp->vm_prev = prev;
506 prev = tmp;
507
508 __vma_link_rb(mm, tmp, rb_link, rb_parent);
509 rb_link = &tmp->vm_rb.rb_right;
510 rb_parent = &tmp->vm_rb;
511
512 mm->map_count++;
513 retval = copy_page_range(mm, oldmm, mpnt);
514
515 if (tmp->vm_ops && tmp->vm_ops->open)
516 tmp->vm_ops->open(tmp);
517
518 if (retval)
519 goto out;
520 }
521
522 arch_dup_mmap(oldmm, mm);
523 retval = 0;
524out:
525 up_write(&mm->mmap_sem);
526 flush_tlb_mm(oldmm);
527 up_write(&oldmm->mmap_sem);
528 uprobe_end_dup_mmap();
529 return retval;
530fail_nomem_anon_vma_fork:
531 mpol_put(vma_policy(tmp));
532fail_nomem_policy:
533 kmem_cache_free(vm_area_cachep, tmp);
534fail_nomem:
535 retval = -ENOMEM;
536 vm_unacct_memory(charge);
537 goto out;
538}
539
540static inline int mm_alloc_pgd(struct mm_struct *mm)
541{
542 mm->pgd = pgd_alloc(mm);
543 if (unlikely(!mm->pgd))
544 return -ENOMEM;
545 return 0;
546}
547
548static inline void mm_free_pgd(struct mm_struct *mm)
549{
550 pgd_free(mm, mm->pgd);
551}
552#else
553static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
554{
555 down_write(&oldmm->mmap_sem);
556 RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
557 up_write(&oldmm->mmap_sem);
558 return 0;
559}
560#define mm_alloc_pgd(mm) (0)
561#define mm_free_pgd(mm)
562#endif
563
564__cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
565
566#define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
567#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
568
569static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
570
571static int __init coredump_filter_setup(char *s)
572{
573 default_dump_filter =
574 (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
575 MMF_DUMP_FILTER_MASK;
576 return 1;
577}
578
579__setup("coredump_filter=", coredump_filter_setup);
580
581#include <linux/init_task.h>
582
583static void mm_init_aio(struct mm_struct *mm)
584{
585#ifdef CONFIG_AIO
586 spin_lock_init(&mm->ioctx_lock);
587 mm->ioctx_table = NULL;
588#endif
589}
590
591static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
592{
593#ifdef CONFIG_MEMCG
594 mm->owner = p;
595#endif
596}
597
598static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
599{
600 mm->mmap = NULL;
601 mm->mm_rb = RB_ROOT;
602 mm->vmacache_seqnum = 0;
603 atomic_set(&mm->mm_users, 1);
604 atomic_set(&mm->mm_count, 1);
605 init_rwsem(&mm->mmap_sem);
606 INIT_LIST_HEAD(&mm->mmlist);
607 mm->core_state = NULL;
608 atomic_long_set(&mm->nr_ptes, 0);
609 mm_nr_pmds_init(mm);
610 mm->map_count = 0;
611 mm->locked_vm = 0;
612 mm->pinned_vm = 0;
613 memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
614 spin_lock_init(&mm->page_table_lock);
615 mm_init_cpumask(mm);
616 mm_init_aio(mm);
617 mm_init_owner(mm, p);
618 mmu_notifier_mm_init(mm);
619 clear_tlb_flush_pending(mm);
620#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
621 mm->pmd_huge_pte = NULL;
622#endif
623
624 if (current->mm) {
625 mm->flags = current->mm->flags & MMF_INIT_MASK;
626 mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK;
627 } else {
628 mm->flags = default_dump_filter;
629 mm->def_flags = 0;
630 }
631
632 if (mm_alloc_pgd(mm))
633 goto fail_nopgd;
634
635 if (init_new_context(p, mm))
636 goto fail_nocontext;
637
638 return mm;
639
640fail_nocontext:
641 mm_free_pgd(mm);
642fail_nopgd:
643 free_mm(mm);
644 return NULL;
645}
646
647static void check_mm(struct mm_struct *mm)
648{
649 int i;
650
651 for (i = 0; i < NR_MM_COUNTERS; i++) {
652 long x = atomic_long_read(&mm->rss_stat.count[i]);
653
654 if (unlikely(x))
655 printk(KERN_ALERT "BUG: Bad rss-counter state "
656 "mm:%p idx:%d val:%ld\n", mm, i, x);
657 }
658
659 if (atomic_long_read(&mm->nr_ptes))
660 pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld\n",
661 atomic_long_read(&mm->nr_ptes));
662 if (mm_nr_pmds(mm))
663 pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld\n",
664 mm_nr_pmds(mm));
665
666#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
667 VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
668#endif
669}
670
671
672
673
674struct mm_struct *mm_alloc(void)
675{
676 struct mm_struct *mm;
677
678 mm = allocate_mm();
679 if (!mm)
680 return NULL;
681
682 memset(mm, 0, sizeof(*mm));
683 return mm_init(mm, current);
684}
685
686
687
688
689
690
691void __mmdrop(struct mm_struct *mm)
692{
693 BUG_ON(mm == &init_mm);
694 mm_free_pgd(mm);
695 destroy_context(mm);
696 mmu_notifier_mm_destroy(mm);
697 check_mm(mm);
698 free_mm(mm);
699}
700EXPORT_SYMBOL_GPL(__mmdrop);
701
702
703
704
705void mmput(struct mm_struct *mm)
706{
707 might_sleep();
708
709 if (atomic_dec_and_test(&mm->mm_users)) {
710 uprobe_clear_state(mm);
711 exit_aio(mm);
712 ksm_exit(mm);
713 khugepaged_exit(mm);
714 exit_mmap(mm);
715 set_mm_exe_file(mm, NULL);
716 if (!list_empty(&mm->mmlist)) {
717 spin_lock(&mmlist_lock);
718 list_del(&mm->mmlist);
719 spin_unlock(&mmlist_lock);
720 }
721 if (mm->binfmt)
722 module_put(mm->binfmt->module);
723 mmdrop(mm);
724 }
725}
726EXPORT_SYMBOL_GPL(mmput);
727
728
729
730
731
732
733
734
735
736
737
738
739void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
740{
741 struct file *old_exe_file;
742
743
744
745
746
747
748 old_exe_file = rcu_dereference_raw(mm->exe_file);
749
750 if (new_exe_file)
751 get_file(new_exe_file);
752 rcu_assign_pointer(mm->exe_file, new_exe_file);
753 if (old_exe_file)
754 fput(old_exe_file);
755}
756
757
758
759
760
761
762
763struct file *get_mm_exe_file(struct mm_struct *mm)
764{
765 struct file *exe_file;
766
767 rcu_read_lock();
768 exe_file = rcu_dereference(mm->exe_file);
769 if (exe_file && !get_file_rcu(exe_file))
770 exe_file = NULL;
771 rcu_read_unlock();
772 return exe_file;
773}
774EXPORT_SYMBOL(get_mm_exe_file);
775
776
777
778
779
780
781
782
783
784
785struct mm_struct *get_task_mm(struct task_struct *task)
786{
787 struct mm_struct *mm;
788
789 task_lock(task);
790 mm = task->mm;
791 if (mm) {
792 if (task->flags & PF_KTHREAD)
793 mm = NULL;
794 else
795 atomic_inc(&mm->mm_users);
796 }
797 task_unlock(task);
798 return mm;
799}
800EXPORT_SYMBOL_GPL(get_task_mm);
801
802struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
803{
804 struct mm_struct *mm;
805 int err;
806
807 err = mutex_lock_killable(&task->signal->cred_guard_mutex);
808 if (err)
809 return ERR_PTR(err);
810
811 mm = get_task_mm(task);
812 if (mm && mm != current->mm &&
813 !ptrace_may_access(task, mode)) {
814 mmput(mm);
815 mm = ERR_PTR(-EACCES);
816 }
817 mutex_unlock(&task->signal->cred_guard_mutex);
818
819 return mm;
820}
821
822static void complete_vfork_done(struct task_struct *tsk)
823{
824 struct completion *vfork;
825
826 task_lock(tsk);
827 vfork = tsk->vfork_done;
828 if (likely(vfork)) {
829 tsk->vfork_done = NULL;
830 complete(vfork);
831 }
832 task_unlock(tsk);
833}
834
835static int wait_for_vfork_done(struct task_struct *child,
836 struct completion *vfork)
837{
838 int killed;
839
840 freezer_do_not_count();
841 killed = wait_for_completion_killable(vfork);
842 freezer_count();
843
844 if (killed) {
845 task_lock(child);
846 child->vfork_done = NULL;
847 task_unlock(child);
848 }
849
850 put_task_struct(child);
851 return killed;
852}
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867void mm_release(struct task_struct *tsk, struct mm_struct *mm)
868{
869
870#ifdef CONFIG_FUTEX
871 if (unlikely(tsk->robust_list)) {
872 exit_robust_list(tsk);
873 tsk->robust_list = NULL;
874 }
875#ifdef CONFIG_COMPAT
876 if (unlikely(tsk->compat_robust_list)) {
877 compat_exit_robust_list(tsk);
878 tsk->compat_robust_list = NULL;
879 }
880#endif
881 if (unlikely(!list_empty(&tsk->pi_state_list)))
882 exit_pi_state_list(tsk);
883#endif
884
885 uprobe_free_utask(tsk);
886
887
888 deactivate_mm(tsk, mm);
889
890
891
892
893
894
895
896
897 if (tsk->clear_child_tid) {
898 if (!(tsk->flags & PF_SIGNALED) &&
899 atomic_read(&mm->mm_users) > 1) {
900
901
902
903
904 put_user(0, tsk->clear_child_tid);
905 sys_futex(tsk->clear_child_tid, FUTEX_WAKE,
906 1, NULL, NULL, 0);
907 }
908 tsk->clear_child_tid = NULL;
909 }
910
911
912
913
914
915 if (tsk->vfork_done)
916 complete_vfork_done(tsk);
917}
918
919
920
921
922
923static struct mm_struct *dup_mm(struct task_struct *tsk)
924{
925 struct mm_struct *mm, *oldmm = current->mm;
926 int err;
927
928 mm = allocate_mm();
929 if (!mm)
930 goto fail_nomem;
931
932 memcpy(mm, oldmm, sizeof(*mm));
933
934 if (!mm_init(mm, tsk))
935 goto fail_nomem;
936
937 err = dup_mmap(mm, oldmm);
938 if (err)
939 goto free_pt;
940
941 mm->hiwater_rss = get_mm_rss(mm);
942 mm->hiwater_vm = mm->total_vm;
943
944 if (mm->binfmt && !try_module_get(mm->binfmt->module))
945 goto free_pt;
946
947 return mm;
948
949free_pt:
950
951 mm->binfmt = NULL;
952 mmput(mm);
953
954fail_nomem:
955 return NULL;
956}
957
958static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
959{
960 struct mm_struct *mm, *oldmm;
961 int retval;
962
963 tsk->min_flt = tsk->maj_flt = 0;
964 tsk->nvcsw = tsk->nivcsw = 0;
965#ifdef CONFIG_DETECT_HUNG_TASK
966 tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
967#endif
968
969 tsk->mm = NULL;
970 tsk->active_mm = NULL;
971
972
973
974
975
976
977 oldmm = current->mm;
978 if (!oldmm)
979 return 0;
980
981
982 vmacache_flush(tsk);
983
984 if (clone_flags & CLONE_VM) {
985 atomic_inc(&oldmm->mm_users);
986 mm = oldmm;
987 goto good_mm;
988 }
989
990 retval = -ENOMEM;
991 mm = dup_mm(tsk);
992 if (!mm)
993 goto fail_nomem;
994
995good_mm:
996 tsk->mm = mm;
997 tsk->active_mm = mm;
998 return 0;
999
1000fail_nomem:
1001 return retval;
1002}
1003
1004static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
1005{
1006 struct fs_struct *fs = current->fs;
1007 if (clone_flags & CLONE_FS) {
1008
1009 spin_lock(&fs->lock);
1010 if (fs->in_exec) {
1011 spin_unlock(&fs->lock);
1012 return -EAGAIN;
1013 }
1014 fs->users++;
1015 spin_unlock(&fs->lock);
1016 return 0;
1017 }
1018 tsk->fs = copy_fs_struct(fs);
1019 if (!tsk->fs)
1020 return -ENOMEM;
1021 return 0;
1022}
1023
1024static int copy_files(unsigned long clone_flags, struct task_struct *tsk)
1025{
1026 struct files_struct *oldf, *newf;
1027 int error = 0;
1028
1029
1030
1031
1032 oldf = current->files;
1033 if (!oldf)
1034 goto out;
1035
1036 if (clone_flags & CLONE_FILES) {
1037 atomic_inc(&oldf->count);
1038 goto out;
1039 }
1040
1041 newf = dup_fd(oldf, &error);
1042 if (!newf)
1043 goto out;
1044
1045 tsk->files = newf;
1046 error = 0;
1047out:
1048 return error;
1049}
1050
1051static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
1052{
1053#ifdef CONFIG_BLOCK
1054 struct io_context *ioc = current->io_context;
1055 struct io_context *new_ioc;
1056
1057 if (!ioc)
1058 return 0;
1059
1060
1061
1062 if (clone_flags & CLONE_IO) {
1063 ioc_task_link(ioc);
1064 tsk->io_context = ioc;
1065 } else if (ioprio_valid(ioc->ioprio)) {
1066 new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
1067 if (unlikely(!new_ioc))
1068 return -ENOMEM;
1069
1070 new_ioc->ioprio = ioc->ioprio;
1071 put_io_context(new_ioc);
1072 }
1073#endif
1074 return 0;
1075}
1076
1077static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
1078{
1079 struct sighand_struct *sig;
1080
1081 if (clone_flags & CLONE_SIGHAND) {
1082 atomic_inc(¤t->sighand->count);
1083 return 0;
1084 }
1085 sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
1086 rcu_assign_pointer(tsk->sighand, sig);
1087 if (!sig)
1088 return -ENOMEM;
1089
1090 atomic_set(&sig->count, 1);
1091 memcpy(sig->action, current->sighand->action, sizeof(sig->action));
1092 return 0;
1093}
1094
1095void __cleanup_sighand(struct sighand_struct *sighand)
1096{
1097 if (atomic_dec_and_test(&sighand->count)) {
1098 signalfd_cleanup(sighand);
1099
1100
1101
1102
1103 kmem_cache_free(sighand_cachep, sighand);
1104 }
1105}
1106
1107
1108
1109
1110static void posix_cpu_timers_init_group(struct signal_struct *sig)
1111{
1112 unsigned long cpu_limit;
1113
1114 cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
1115 if (cpu_limit != RLIM_INFINITY) {
1116 sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
1117 sig->cputimer.running = true;
1118 }
1119
1120
1121 INIT_LIST_HEAD(&sig->cpu_timers[0]);
1122 INIT_LIST_HEAD(&sig->cpu_timers[1]);
1123 INIT_LIST_HEAD(&sig->cpu_timers[2]);
1124}
1125
1126static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
1127{
1128 struct signal_struct *sig;
1129
1130 if (clone_flags & CLONE_THREAD)
1131 return 0;
1132
1133 sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
1134 tsk->signal = sig;
1135 if (!sig)
1136 return -ENOMEM;
1137
1138 sig->nr_threads = 1;
1139 atomic_set(&sig->live, 1);
1140 atomic_set(&sig->sigcnt, 1);
1141
1142
1143 sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
1144 tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);
1145
1146 init_waitqueue_head(&sig->wait_chldexit);
1147 sig->curr_target = tsk;
1148 init_sigpending(&sig->shared_pending);
1149 INIT_LIST_HEAD(&sig->posix_timers);
1150 seqlock_init(&sig->stats_lock);
1151 prev_cputime_init(&sig->prev_cputime);
1152
1153 hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1154 sig->real_timer.function = it_real_fn;
1155
1156 task_lock(current->group_leader);
1157 memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
1158 task_unlock(current->group_leader);
1159
1160 posix_cpu_timers_init_group(sig);
1161
1162 tty_audit_fork(sig);
1163 sched_autogroup_fork(sig);
1164
1165 sig->oom_score_adj = current->signal->oom_score_adj;
1166 sig->oom_score_adj_min = current->signal->oom_score_adj_min;
1167
1168 sig->has_child_subreaper = current->signal->has_child_subreaper ||
1169 current->signal->is_child_subreaper;
1170
1171 mutex_init(&sig->cred_guard_mutex);
1172
1173 return 0;
1174}
1175
1176static void copy_seccomp(struct task_struct *p)
1177{
1178#ifdef CONFIG_SECCOMP
1179
1180
1181
1182
1183
1184
1185 assert_spin_locked(¤t->sighand->siglock);
1186
1187
1188 get_seccomp_filter(current);
1189 p->seccomp = current->seccomp;
1190
1191
1192
1193
1194
1195
1196 if (task_no_new_privs(current))
1197 task_set_no_new_privs(p);
1198
1199
1200
1201
1202
1203
1204 if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
1205 set_tsk_thread_flag(p, TIF_SECCOMP);
1206#endif
1207}
1208
1209SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
1210{
1211 current->clear_child_tid = tidptr;
1212
1213 return task_pid_vnr(current);
1214}
1215
1216static void rt_mutex_init_task(struct task_struct *p)
1217{
1218 raw_spin_lock_init(&p->pi_lock);
1219#ifdef CONFIG_RT_MUTEXES
1220 p->pi_waiters = RB_ROOT;
1221 p->pi_waiters_leftmost = NULL;
1222 p->pi_blocked_on = NULL;
1223#endif
1224}
1225
1226
1227
1228
1229static void posix_cpu_timers_init(struct task_struct *tsk)
1230{
1231 tsk->cputime_expires.prof_exp = 0;
1232 tsk->cputime_expires.virt_exp = 0;
1233 tsk->cputime_expires.sched_exp = 0;
1234 INIT_LIST_HEAD(&tsk->cpu_timers[0]);
1235 INIT_LIST_HEAD(&tsk->cpu_timers[1]);
1236 INIT_LIST_HEAD(&tsk->cpu_timers[2]);
1237}
1238
1239static inline void
1240init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
1241{
1242 task->pids[type].pid = pid;
1243}
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253static struct task_struct *copy_process(unsigned long clone_flags,
1254 unsigned long stack_start,
1255 unsigned long stack_size,
1256 int __user *child_tidptr,
1257 struct pid *pid,
1258 int trace,
1259 unsigned long tls)
1260{
1261 int retval;
1262 struct task_struct *p;
1263
1264 if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
1265 return ERR_PTR(-EINVAL);
1266
1267 if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
1268 return ERR_PTR(-EINVAL);
1269
1270
1271
1272
1273
1274 if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
1275 return ERR_PTR(-EINVAL);
1276
1277
1278
1279
1280
1281
1282 if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
1283 return ERR_PTR(-EINVAL);
1284
1285
1286
1287
1288
1289
1290
1291 if ((clone_flags & CLONE_PARENT) &&
1292 current->signal->flags & SIGNAL_UNKILLABLE)
1293 return ERR_PTR(-EINVAL);
1294
1295
1296
1297
1298
1299 if (clone_flags & CLONE_THREAD) {
1300 if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
1301 (task_active_pid_ns(current) !=
1302 current->nsproxy->pid_ns_for_children))
1303 return ERR_PTR(-EINVAL);
1304 }
1305
1306 retval = security_task_create(clone_flags);
1307 if (retval)
1308 goto fork_out;
1309
1310 retval = -ENOMEM;
1311 p = dup_task_struct(current);
1312 if (!p)
1313 goto fork_out;
1314
1315 ftrace_graph_init_task(p);
1316
1317 rt_mutex_init_task(p);
1318
1319#ifdef CONFIG_PROVE_LOCKING
1320 DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
1321 DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
1322#endif
1323 retval = -EAGAIN;
1324 if (atomic_read(&p->real_cred->user->processes) >=
1325 task_rlimit(p, RLIMIT_NPROC)) {
1326 if (p->real_cred->user != INIT_USER &&
1327 !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
1328 goto bad_fork_free;
1329 }
1330 current->flags &= ~PF_NPROC_EXCEEDED;
1331
1332 retval = copy_creds(p, clone_flags);
1333 if (retval < 0)
1334 goto bad_fork_free;
1335
1336
1337
1338
1339
1340
1341 retval = -EAGAIN;
1342 if (nr_threads >= max_threads)
1343 goto bad_fork_cleanup_count;
1344
1345 delayacct_tsk_init(p);
1346 p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
1347 p->flags |= PF_FORKNOEXEC;
1348 INIT_LIST_HEAD(&p->children);
1349 INIT_LIST_HEAD(&p->sibling);
1350 rcu_copy_process(p);
1351 p->vfork_done = NULL;
1352 spin_lock_init(&p->alloc_lock);
1353
1354 init_sigpending(&p->pending);
1355
1356 p->utime = p->stime = p->gtime = 0;
1357 p->utimescaled = p->stimescaled = 0;
1358 prev_cputime_init(&p->prev_cputime);
1359
1360#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1361 seqcount_init(&p->vtime_seqcount);
1362 p->vtime_snap = 0;
1363 p->vtime_snap_whence = VTIME_INACTIVE;
1364#endif
1365
1366#if defined(SPLIT_RSS_COUNTING)
1367 memset(&p->rss_stat, 0, sizeof(p->rss_stat));
1368#endif
1369
1370 p->default_timer_slack_ns = current->timer_slack_ns;
1371
1372 task_io_accounting_init(&p->ioac);
1373 acct_clear_integrals(p);
1374
1375 posix_cpu_timers_init(p);
1376
1377 p->start_time = ktime_get_ns();
1378 p->real_start_time = ktime_get_boot_ns();
1379 p->io_context = NULL;
1380 p->audit_context = NULL;
1381 threadgroup_change_begin(current);
1382 cgroup_fork(p);
1383#ifdef CONFIG_NUMA
1384 p->mempolicy = mpol_dup(p->mempolicy);
1385 if (IS_ERR(p->mempolicy)) {
1386 retval = PTR_ERR(p->mempolicy);
1387 p->mempolicy = NULL;
1388 goto bad_fork_cleanup_threadgroup_lock;
1389 }
1390#endif
1391#ifdef CONFIG_CPUSETS
1392 p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
1393 p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
1394 seqcount_init(&p->mems_allowed_seq);
1395#endif
1396#ifdef CONFIG_TRACE_IRQFLAGS
1397 p->irq_events = 0;
1398 p->hardirqs_enabled = 0;
1399 p->hardirq_enable_ip = 0;
1400 p->hardirq_enable_event = 0;
1401 p->hardirq_disable_ip = _THIS_IP_;
1402 p->hardirq_disable_event = 0;
1403 p->softirqs_enabled = 1;
1404 p->softirq_enable_ip = _THIS_IP_;
1405 p->softirq_enable_event = 0;
1406 p->softirq_disable_ip = 0;
1407 p->softirq_disable_event = 0;
1408 p->hardirq_context = 0;
1409 p->softirq_context = 0;
1410#endif
1411
1412 p->pagefault_disabled = 0;
1413
1414#ifdef CONFIG_LOCKDEP
1415 p->lockdep_depth = 0;
1416 p->curr_chain_key = 0;
1417 p->lockdep_recursion = 0;
1418#endif
1419
1420#ifdef CONFIG_DEBUG_MUTEXES
1421 p->blocked_on = NULL;
1422#endif
1423#ifdef CONFIG_BCACHE
1424 p->sequential_io = 0;
1425 p->sequential_io_avg = 0;
1426#endif
1427
1428
1429 retval = sched_fork(clone_flags, p);
1430 if (retval)
1431 goto bad_fork_cleanup_policy;
1432
1433 retval = perf_event_init_task(p);
1434 if (retval)
1435 goto bad_fork_cleanup_policy;
1436 retval = audit_alloc(p);
1437 if (retval)
1438 goto bad_fork_cleanup_perf;
1439
1440 shm_init_task(p);
1441 retval = copy_semundo(clone_flags, p);
1442 if (retval)
1443 goto bad_fork_cleanup_audit;
1444 retval = copy_files(clone_flags, p);
1445 if (retval)
1446 goto bad_fork_cleanup_semundo;
1447 retval = copy_fs(clone_flags, p);
1448 if (retval)
1449 goto bad_fork_cleanup_files;
1450 retval = copy_sighand(clone_flags, p);
1451 if (retval)
1452 goto bad_fork_cleanup_fs;
1453 retval = copy_signal(clone_flags, p);
1454 if (retval)
1455 goto bad_fork_cleanup_sighand;
1456 retval = copy_mm(clone_flags, p);
1457 if (retval)
1458 goto bad_fork_cleanup_signal;
1459 retval = copy_namespaces(clone_flags, p);
1460 if (retval)
1461 goto bad_fork_cleanup_mm;
1462 retval = copy_io(clone_flags, p);
1463 if (retval)
1464 goto bad_fork_cleanup_namespaces;
1465 retval = copy_thread_tls(clone_flags, stack_start, stack_size, p, tls);
1466 if (retval)
1467 goto bad_fork_cleanup_io;
1468
1469 if (pid != &init_struct_pid) {
1470 pid = alloc_pid(p->nsproxy->pid_ns_for_children);
1471 if (IS_ERR(pid)) {
1472 retval = PTR_ERR(pid);
1473 goto bad_fork_cleanup_io;
1474 }
1475 }
1476
1477 p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1478
1479
1480
1481 p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL;
1482#ifdef CONFIG_BLOCK
1483 p->plug = NULL;
1484#endif
1485#ifdef CONFIG_FUTEX
1486 p->robust_list = NULL;
1487#ifdef CONFIG_COMPAT
1488 p->compat_robust_list = NULL;
1489#endif
1490 INIT_LIST_HEAD(&p->pi_state_list);
1491 p->pi_state_cache = NULL;
1492#endif
1493
1494
1495
1496 if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
1497 p->sas_ss_sp = p->sas_ss_size = 0;
1498
1499
1500
1501
1502
1503 user_disable_single_step(p);
1504 clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
1505#ifdef TIF_SYSCALL_EMU
1506 clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
1507#endif
1508 clear_all_latency_tracing(p);
1509
1510
1511 p->pid = pid_nr(pid);
1512 if (clone_flags & CLONE_THREAD) {
1513 p->exit_signal = -1;
1514 p->group_leader = current->group_leader;
1515 p->tgid = current->tgid;
1516 } else {
1517 if (clone_flags & CLONE_PARENT)
1518 p->exit_signal = current->group_leader->exit_signal;
1519 else
1520 p->exit_signal = (clone_flags & CSIGNAL);
1521 p->group_leader = p;
1522 p->tgid = p->pid;
1523 }
1524
1525 p->nr_dirtied = 0;
1526 p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
1527 p->dirty_paused_when = 0;
1528
1529 p->pdeath_signal = 0;
1530 INIT_LIST_HEAD(&p->thread_group);
1531 p->task_works = NULL;
1532
1533
1534
1535
1536
1537
1538
1539 retval = cgroup_can_fork(p);
1540 if (retval)
1541 goto bad_fork_free_pid;
1542
1543
1544
1545
1546
1547 write_lock_irq(&tasklist_lock);
1548
1549
1550 if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
1551 p->real_parent = current->real_parent;
1552 p->parent_exec_id = current->parent_exec_id;
1553 } else {
1554 p->real_parent = current;
1555 p->parent_exec_id = current->self_exec_id;
1556 }
1557
1558 spin_lock(¤t->sighand->siglock);
1559
1560
1561
1562
1563
1564 copy_seccomp(p);
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574 recalc_sigpending();
1575 if (signal_pending(current)) {
1576 spin_unlock(¤t->sighand->siglock);
1577 write_unlock_irq(&tasklist_lock);
1578 retval = -ERESTARTNOINTR;
1579 goto bad_fork_cancel_cgroup;
1580 }
1581
1582 if (likely(p->pid)) {
1583 ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
1584
1585 init_task_pid(p, PIDTYPE_PID, pid);
1586 if (thread_group_leader(p)) {
1587 init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
1588 init_task_pid(p, PIDTYPE_SID, task_session(current));
1589
1590 if (is_child_reaper(pid)) {
1591 ns_of_pid(pid)->child_reaper = p;
1592 p->signal->flags |= SIGNAL_UNKILLABLE;
1593 }
1594
1595 p->signal->leader_pid = pid;
1596 p->signal->tty = tty_kref_get(current->signal->tty);
1597 list_add_tail(&p->sibling, &p->real_parent->children);
1598 list_add_tail_rcu(&p->tasks, &init_task.tasks);
1599 attach_pid(p, PIDTYPE_PGID);
1600 attach_pid(p, PIDTYPE_SID);
1601 __this_cpu_inc(process_counts);
1602 } else {
1603 current->signal->nr_threads++;
1604 atomic_inc(¤t->signal->live);
1605 atomic_inc(¤t->signal->sigcnt);
1606 list_add_tail_rcu(&p->thread_group,
1607 &p->group_leader->thread_group);
1608 list_add_tail_rcu(&p->thread_node,
1609 &p->signal->thread_head);
1610 }
1611 attach_pid(p, PIDTYPE_PID);
1612 nr_threads++;
1613 }
1614
1615 total_forks++;
1616 spin_unlock(¤t->sighand->siglock);
1617 syscall_tracepoint_update(p);
1618 write_unlock_irq(&tasklist_lock);
1619
1620 proc_fork_connector(p);
1621 cgroup_post_fork(p);
1622 threadgroup_change_end(current);
1623 perf_event_fork(p);
1624
1625 trace_task_newtask(p, clone_flags);
1626 uprobe_copy_process(p, clone_flags);
1627
1628 return p;
1629
1630bad_fork_cancel_cgroup:
1631 cgroup_cancel_fork(p);
1632bad_fork_free_pid:
1633 if (pid != &init_struct_pid)
1634 free_pid(pid);
1635bad_fork_cleanup_io:
1636 if (p->io_context)
1637 exit_io_context(p);
1638bad_fork_cleanup_namespaces:
1639 exit_task_namespaces(p);
1640bad_fork_cleanup_mm:
1641 if (p->mm)
1642 mmput(p->mm);
1643bad_fork_cleanup_signal:
1644 if (!(clone_flags & CLONE_THREAD))
1645 free_signal_struct(p->signal);
1646bad_fork_cleanup_sighand:
1647 __cleanup_sighand(p->sighand);
1648bad_fork_cleanup_fs:
1649 exit_fs(p);
1650bad_fork_cleanup_files:
1651 exit_files(p);
1652bad_fork_cleanup_semundo:
1653 exit_sem(p);
1654bad_fork_cleanup_audit:
1655 audit_free(p);
1656bad_fork_cleanup_perf:
1657 perf_event_free_task(p);
1658bad_fork_cleanup_policy:
1659#ifdef CONFIG_NUMA
1660 mpol_put(p->mempolicy);
1661bad_fork_cleanup_threadgroup_lock:
1662#endif
1663 threadgroup_change_end(current);
1664 delayacct_tsk_free(p);
1665bad_fork_cleanup_count:
1666 atomic_dec(&p->cred->user->processes);
1667 exit_creds(p);
1668bad_fork_free:
1669 free_task(p);
1670fork_out:
1671 return ERR_PTR(retval);
1672}
1673
1674static inline void init_idle_pids(struct pid_link *links)
1675{
1676 enum pid_type type;
1677
1678 for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
1679 INIT_HLIST_NODE(&links[type].node);
1680 links[type].pid = &init_struct_pid;
1681 }
1682}
1683
1684struct task_struct *fork_idle(int cpu)
1685{
1686 struct task_struct *task;
1687 task = copy_process(CLONE_VM, 0, 0, NULL, &init_struct_pid, 0, 0);
1688 if (!IS_ERR(task)) {
1689 init_idle_pids(task->pids);
1690 init_idle(task, cpu);
1691 }
1692
1693 return task;
1694}
1695
1696
1697
1698
1699
1700
1701
1702long _do_fork(unsigned long clone_flags,
1703 unsigned long stack_start,
1704 unsigned long stack_size,
1705 int __user *parent_tidptr,
1706 int __user *child_tidptr,
1707 unsigned long tls)
1708{
1709 struct task_struct *p;
1710 int trace = 0;
1711 long nr;
1712
1713
1714
1715
1716
1717
1718
1719 if (!(clone_flags & CLONE_UNTRACED)) {
1720 if (clone_flags & CLONE_VFORK)
1721 trace = PTRACE_EVENT_VFORK;
1722 else if ((clone_flags & CSIGNAL) != SIGCHLD)
1723 trace = PTRACE_EVENT_CLONE;
1724 else
1725 trace = PTRACE_EVENT_FORK;
1726
1727 if (likely(!ptrace_event_enabled(current, trace)))
1728 trace = 0;
1729 }
1730
1731 p = copy_process(clone_flags, stack_start, stack_size,
1732 child_tidptr, NULL, trace, tls);
1733
1734
1735
1736
1737 if (!IS_ERR(p)) {
1738 struct completion vfork;
1739 struct pid *pid;
1740
1741 trace_sched_process_fork(current, p);
1742
1743 pid = get_task_pid(p, PIDTYPE_PID);
1744 nr = pid_vnr(pid);
1745
1746 if (clone_flags & CLONE_PARENT_SETTID)
1747 put_user(nr, parent_tidptr);
1748
1749 if (clone_flags & CLONE_VFORK) {
1750 p->vfork_done = &vfork;
1751 init_completion(&vfork);
1752 get_task_struct(p);
1753 }
1754
1755 wake_up_new_task(p);
1756
1757
1758 if (unlikely(trace))
1759 ptrace_event_pid(trace, pid);
1760
1761 if (clone_flags & CLONE_VFORK) {
1762 if (!wait_for_vfork_done(p, &vfork))
1763 ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
1764 }
1765
1766 put_pid(pid);
1767 } else {
1768 nr = PTR_ERR(p);
1769 }
1770 return nr;
1771}
1772
1773#ifndef CONFIG_HAVE_COPY_THREAD_TLS
1774
1775
1776long do_fork(unsigned long clone_flags,
1777 unsigned long stack_start,
1778 unsigned long stack_size,
1779 int __user *parent_tidptr,
1780 int __user *child_tidptr)
1781{
1782 return _do_fork(clone_flags, stack_start, stack_size,
1783 parent_tidptr, child_tidptr, 0);
1784}
1785#endif
1786
1787
1788
1789
1790pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
1791{
1792 return _do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn,
1793 (unsigned long)arg, NULL, NULL, 0);
1794}
1795
1796#ifdef __ARCH_WANT_SYS_FORK
1797SYSCALL_DEFINE0(fork)
1798{
1799#ifdef CONFIG_MMU
1800 return _do_fork(SIGCHLD, 0, 0, NULL, NULL, 0);
1801#else
1802
1803 return -EINVAL;
1804#endif
1805}
1806#endif
1807
1808#ifdef __ARCH_WANT_SYS_VFORK
1809SYSCALL_DEFINE0(vfork)
1810{
1811 return _do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
1812 0, NULL, NULL, 0);
1813}
1814#endif
1815
1816#ifdef __ARCH_WANT_SYS_CLONE
1817#ifdef CONFIG_CLONE_BACKWARDS
1818SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
1819 int __user *, parent_tidptr,
1820 unsigned long, tls,
1821 int __user *, child_tidptr)
1822#elif defined(CONFIG_CLONE_BACKWARDS2)
1823SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags,
1824 int __user *, parent_tidptr,
1825 int __user *, child_tidptr,
1826 unsigned long, tls)
1827#elif defined(CONFIG_CLONE_BACKWARDS3)
1828SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
1829 int, stack_size,
1830 int __user *, parent_tidptr,
1831 int __user *, child_tidptr,
1832 unsigned long, tls)
1833#else
1834SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
1835 int __user *, parent_tidptr,
1836 int __user *, child_tidptr,
1837 unsigned long, tls)
1838#endif
1839{
1840 return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr, tls);
1841}
1842#endif
1843
1844#ifndef ARCH_MIN_MMSTRUCT_ALIGN
1845#define ARCH_MIN_MMSTRUCT_ALIGN 0
1846#endif
1847
1848static void sighand_ctor(void *data)
1849{
1850 struct sighand_struct *sighand = data;
1851
1852 spin_lock_init(&sighand->siglock);
1853 init_waitqueue_head(&sighand->signalfd_wqh);
1854}
1855
1856void __init proc_caches_init(void)
1857{
1858 sighand_cachep = kmem_cache_create("sighand_cache",
1859 sizeof(struct sighand_struct), 0,
1860 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU|
1861 SLAB_NOTRACK|SLAB_ACCOUNT, sighand_ctor);
1862 signal_cachep = kmem_cache_create("signal_cache",
1863 sizeof(struct signal_struct), 0,
1864 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT,
1865 NULL);
1866 files_cachep = kmem_cache_create("files_cache",
1867 sizeof(struct files_struct), 0,
1868 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT,
1869 NULL);
1870 fs_cachep = kmem_cache_create("fs_cache",
1871 sizeof(struct fs_struct), 0,
1872 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT,
1873 NULL);
1874
1875
1876
1877
1878
1879
1880
1881 mm_cachep = kmem_cache_create("mm_struct",
1882 sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
1883 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT,
1884 NULL);
1885 vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
1886 mmap_init();
1887 nsproxy_cache_init();
1888}
1889
1890
1891
1892
1893static int check_unshare_flags(unsigned long unshare_flags)
1894{
1895 if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
1896 CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
1897 CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
1898 CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
1899 return -EINVAL;
1900
1901
1902
1903
1904
1905
1906 if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
1907 if (!thread_group_empty(current))
1908 return -EINVAL;
1909 }
1910 if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
1911 if (atomic_read(¤t->sighand->count) > 1)
1912 return -EINVAL;
1913 }
1914 if (unshare_flags & CLONE_VM) {
1915 if (!current_is_single_threaded())
1916 return -EINVAL;
1917 }
1918
1919 return 0;
1920}
1921
1922
1923
1924
1925static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
1926{
1927 struct fs_struct *fs = current->fs;
1928
1929 if (!(unshare_flags & CLONE_FS) || !fs)
1930 return 0;
1931
1932
1933 if (fs->users == 1)
1934 return 0;
1935
1936 *new_fsp = copy_fs_struct(fs);
1937 if (!*new_fsp)
1938 return -ENOMEM;
1939
1940 return 0;
1941}
1942
1943
1944
1945
1946static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
1947{
1948 struct files_struct *fd = current->files;
1949 int error = 0;
1950
1951 if ((unshare_flags & CLONE_FILES) &&
1952 (fd && atomic_read(&fd->count) > 1)) {
1953 *new_fdp = dup_fd(fd, &error);
1954 if (!*new_fdp)
1955 return error;
1956 }
1957
1958 return 0;
1959}
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
1970{
1971 struct fs_struct *fs, *new_fs = NULL;
1972 struct files_struct *fd, *new_fd = NULL;
1973 struct cred *new_cred = NULL;
1974 struct nsproxy *new_nsproxy = NULL;
1975 int do_sysvsem = 0;
1976 int err;
1977
1978
1979
1980
1981
1982 if (unshare_flags & CLONE_NEWUSER)
1983 unshare_flags |= CLONE_THREAD | CLONE_FS;
1984
1985
1986
1987 if (unshare_flags & CLONE_VM)
1988 unshare_flags |= CLONE_SIGHAND;
1989
1990
1991
1992 if (unshare_flags & CLONE_SIGHAND)
1993 unshare_flags |= CLONE_THREAD;
1994
1995
1996
1997 if (unshare_flags & CLONE_NEWNS)
1998 unshare_flags |= CLONE_FS;
1999
2000 err = check_unshare_flags(unshare_flags);
2001 if (err)
2002 goto bad_unshare_out;
2003
2004
2005
2006
2007
2008 if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
2009 do_sysvsem = 1;
2010 err = unshare_fs(unshare_flags, &new_fs);
2011 if (err)
2012 goto bad_unshare_out;
2013 err = unshare_fd(unshare_flags, &new_fd);
2014 if (err)
2015 goto bad_unshare_cleanup_fs;
2016 err = unshare_userns(unshare_flags, &new_cred);
2017 if (err)
2018 goto bad_unshare_cleanup_fd;
2019 err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
2020 new_cred, new_fs);
2021 if (err)
2022 goto bad_unshare_cleanup_cred;
2023
2024 if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
2025 if (do_sysvsem) {
2026
2027
2028
2029 exit_sem(current);
2030 }
2031 if (unshare_flags & CLONE_NEWIPC) {
2032
2033 exit_shm(current);
2034 shm_init_task(current);
2035 }
2036
2037 if (new_nsproxy)
2038 switch_task_namespaces(current, new_nsproxy);
2039
2040 task_lock(current);
2041
2042 if (new_fs) {
2043 fs = current->fs;
2044 spin_lock(&fs->lock);
2045 current->fs = new_fs;
2046 if (--fs->users)
2047 new_fs = NULL;
2048 else
2049 new_fs = fs;
2050 spin_unlock(&fs->lock);
2051 }
2052
2053 if (new_fd) {
2054 fd = current->files;
2055 current->files = new_fd;
2056 new_fd = fd;
2057 }
2058
2059 task_unlock(current);
2060
2061 if (new_cred) {
2062
2063 commit_creds(new_cred);
2064 new_cred = NULL;
2065 }
2066 }
2067
2068bad_unshare_cleanup_cred:
2069 if (new_cred)
2070 put_cred(new_cred);
2071bad_unshare_cleanup_fd:
2072 if (new_fd)
2073 put_files_struct(new_fd);
2074
2075bad_unshare_cleanup_fs:
2076 if (new_fs)
2077 free_fs_struct(new_fs);
2078
2079bad_unshare_out:
2080 return err;
2081}
2082
2083
2084
2085
2086
2087
2088
2089int unshare_files(struct files_struct **displaced)
2090{
2091 struct task_struct *task = current;
2092 struct files_struct *copy = NULL;
2093 int error;
2094
2095 error = unshare_fd(CLONE_FILES, ©);
2096 if (error || !copy) {
2097 *displaced = NULL;
2098 return error;
2099 }
2100 *displaced = task->files;
2101 task_lock(task);
2102 task->files = copy;
2103 task_unlock(task);
2104 return 0;
2105}
2106
2107int sysctl_max_threads(struct ctl_table *table, int write,
2108 void __user *buffer, size_t *lenp, loff_t *ppos)
2109{
2110 struct ctl_table t;
2111 int ret;
2112 int threads = max_threads;
2113 int min = MIN_THREADS;
2114 int max = MAX_THREADS;
2115
2116 t = *table;
2117 t.data = &threads;
2118 t.extra1 = &min;
2119 t.extra2 = &max;
2120
2121 ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
2122 if (ret || !write)
2123 return ret;
2124
2125 set_max_threads(threads);
2126
2127 return 0;
2128}
2129