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