blob: 9ee58bb9e60fb0602755445c672c067db8f72ea4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/exit.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/mm.h>
8#include <linux/slab.h>
9#include <linux/interrupt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/module.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080011#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/completion.h>
13#include <linux/personality.h>
14#include <linux/tty.h>
Jens Axboeda9cbc82008-06-30 20:42:08 +020015#include <linux/iocontext.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/key.h>
17#include <linux/security.h>
18#include <linux/cpu.h>
19#include <linux/acct.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070020#include <linux/tsacct_kern.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -040022#include <linux/fdtable.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/binfmts.h>
Serge E. Hallynab516012006-10-02 02:18:06 -070024#include <linux/nsproxy.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080025#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/ptrace.h>
27#include <linux/profile.h>
28#include <linux/mount.h>
29#include <linux/proc_fs.h>
Eric W. Biederman49d769d2007-05-09 02:34:33 -070030#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/mempolicy.h>
Shailabh Nagarc7572492006-07-14 00:24:40 -070032#include <linux/taskstats_kern.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070033#include <linux/delayacct.h>
Rafael J. Wysocki83144182007-07-17 04:03:35 -070034#include <linux/freezer.h>
Paul Menageb4f48b62007-10-18 23:39:33 -070035#include <linux/cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <linux/syscalls.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070037#include <linux/signal.h>
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080038#include <linux/posix-timers.h>
Matt Helsley9f460802005-11-07 00:59:16 -080039#include <linux/cn_proc.h>
Ingo Molnarde5097c2006-01-09 15:59:21 -080040#include <linux/mutex.h>
Ingo Molnar0771dfe2006-03-27 01:16:22 -080041#include <linux/futex.h>
Jens Axboeb92ce552006-04-11 13:52:07 +020042#include <linux/pipe_fs_i.h>
Al Virofa84cb92006-03-29 20:30:19 -050043#include <linux/audit.h> /* for audit_free() */
Adrian Bunk83cc5ed2006-06-25 05:47:41 -070044#include <linux/resource.h>
David Howells0d67a462006-08-29 19:05:56 +010045#include <linux/blkdev.h>
Eric Dumazet6eaeeab2007-05-10 22:22:37 -070046#include <linux/task_io_accounting_ops.h>
Roland McGrath30199f52008-07-25 19:45:46 -070047#include <linux/tracehook.h>
Al Viro5ad4e532009-03-29 19:50:06 -040048#include <linux/fs_struct.h>
David Howellsd84f4f92008-11-14 10:39:23 +110049#include <linux/init_task.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020050#include <linux/perf_event.h>
Steven Rostedtad8d75f2009-04-14 19:39:12 -040051#include <trace/events/sched.h>
Frederic Weisbecker24f1e32c2009-09-09 19:22:48 +020052#include <linux/hw_breakpoint.h>
Ying Han3d5992d2010-10-26 14:21:23 -070053#include <linux/oom.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55#include <asm/uaccess.h>
56#include <asm/unistd.h>
57#include <asm/pgtable.h>
58#include <asm/mmu_context.h>
59
Adrian Bunk408b6642005-05-01 08:59:29 -070060static void exit_mm(struct task_struct * tsk);
61
Oleg Nesterovd40e48e2010-05-26 14:43:19 -070062static void __unhash_process(struct task_struct *p, bool group_dead)
Linus Torvalds1da177e2005-04-16 15:20:36 -070063{
64 nr_threads--;
65 detach_pid(p, PIDTYPE_PID);
Oleg Nesterovd40e48e2010-05-26 14:43:19 -070066 if (group_dead) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 detach_pid(p, PIDTYPE_PGID);
68 detach_pid(p, PIDTYPE_SID);
Oleg Nesterovc97d9892006-03-28 16:11:06 -080069
Eric W. Biederman5e85d4a2006-04-18 22:20:16 -070070 list_del_rcu(&p->tasks);
Oleg Nesterov9cd80bb2009-12-17 15:27:15 -080071 list_del_init(&p->sibling);
Christoph Lameter909ea962010-12-08 16:22:55 +010072 __this_cpu_dec(process_counts);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 }
Oleg Nesterov47e65322006-03-28 16:11:25 -080074 list_del_rcu(&p->thread_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075}
76
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080077/*
78 * This function expects the tasklist_lock write-locked.
79 */
80static void __exit_signal(struct task_struct *tsk)
81{
82 struct signal_struct *sig = tsk->signal;
Oleg Nesterovd40e48e2010-05-26 14:43:19 -070083 bool group_dead = thread_group_leader(tsk);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080084 struct sighand_struct *sighand;
Oleg Nesterov4ada8562010-05-26 14:43:17 -070085 struct tty_struct *uninitialized_var(tty);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080086
Paul E. McKenneyd11c5632010-02-22 17:04:50 -080087 sighand = rcu_dereference_check(tsk->sighand,
Paul E. McKenneydb1466b2010-03-03 07:46:56 -080088 lockdep_tasklist_lock_is_held());
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080089 spin_lock(&sighand->siglock);
90
91 posix_cpu_timers_exit(tsk);
Oleg Nesterovd40e48e2010-05-26 14:43:19 -070092 if (group_dead) {
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080093 posix_cpu_timers_exit_group(tsk);
Oleg Nesterov4ada8562010-05-26 14:43:17 -070094 tty = sig->tty;
95 sig->tty = NULL;
Oleg Nesterov4a599942010-05-26 14:43:12 -070096 } else {
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080097 /*
Oleg Nesterove0a70212010-11-05 16:53:42 +010098 * This can only happen if the caller is de_thread().
99 * FIXME: this is the temporary hack, we should teach
100 * posix-cpu-timers to handle this case correctly.
101 */
102 if (unlikely(has_group_leader_pid(tsk)))
103 posix_cpu_timers_exit_group(tsk);
104
105 /*
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800106 * If there is any task waiting for the group exit
107 * then notify it:
108 */
Oleg Nesterovd3441932010-05-26 14:43:11 -0700109 if (sig->notify_count > 0 && !--sig->notify_count)
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800110 wake_up_process(sig->group_exit_task);
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700111
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800112 if (tsk == sig->curr_target)
113 sig->curr_target = next_thread(tsk);
114 /*
115 * Accumulate here the counters for all threads but the
116 * group leader as they die, so they can be added into
117 * the process-wide totals when those are taken.
118 * The group leader stays around as a zombie as long
119 * as there are other threads. When it gets reaped,
120 * the exit.c code will add its counts into these totals.
121 * We won't ever get here for the group leader, since it
122 * will have been the last reference on the signal_struct.
123 */
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +0900124 sig->utime = cputime_add(sig->utime, tsk->utime);
125 sig->stime = cputime_add(sig->stime, tsk->stime);
Hidetoshi Setod5b7c782009-11-26 14:49:05 +0900126 sig->gtime = cputime_add(sig->gtime, tsk->gtime);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800127 sig->min_flt += tsk->min_flt;
128 sig->maj_flt += tsk->maj_flt;
129 sig->nvcsw += tsk->nvcsw;
130 sig->nivcsw += tsk->nivcsw;
Eric Dumazet6eaeeab2007-05-10 22:22:37 -0700131 sig->inblock += task_io_get_inblock(tsk);
132 sig->oublock += task_io_get_oublock(tsk);
Andrea Righi59954772008-07-27 17:29:15 +0200133 task_io_accounting_add(&sig->ioac, &tsk->ioac);
Peter Zijlstra32bd6712009-02-05 12:24:15 +0100134 sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800135 }
136
Oleg Nesterovb3ac0222010-05-26 14:43:24 -0700137 sig->nr_threads--;
Oleg Nesterovd40e48e2010-05-26 14:43:19 -0700138 __unhash_process(tsk, group_dead);
Oleg Nesterov58767002006-03-28 16:11:20 -0800139
Oleg Nesterovda7978b2008-05-23 13:04:41 -0700140 /*
141 * Do this under ->siglock, we can race with another thread
142 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
143 */
144 flush_sigqueue(&tsk->pending);
Oleg Nesterova7e53282006-03-28 16:11:27 -0800145 tsk->sighand = NULL;
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800146 spin_unlock(&sighand->siglock);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800147
Oleg Nesterova7e53282006-03-28 16:11:27 -0800148 __cleanup_sighand(sighand);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800149 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
Oleg Nesterovd40e48e2010-05-26 14:43:19 -0700150 if (group_dead) {
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800151 flush_sigqueue(&sig->shared_pending);
Oleg Nesterov4ada8562010-05-26 14:43:17 -0700152 tty_kref_put(tty);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800153 }
154}
155
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800156static void delayed_put_task_struct(struct rcu_head *rhp)
157{
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -0400158 struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
159
Peter Zijlstra4e231c72010-09-09 21:01:59 +0200160 perf_event_delayed_put(tsk);
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -0400161 trace_sched_process_free(tsk);
162 put_task_struct(tsk);
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800163}
164
Roland McGrathf4700212008-03-24 18:36:23 -0700165
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166void release_task(struct task_struct * p)
167{
Ingo Molnar36c8b582006-07-03 00:25:41 -0700168 struct task_struct *leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 int zap_leader;
Oleg Nesterov1f09f972006-03-28 16:11:11 -0800170repeat:
David Howellsc69e8d92008-11-14 10:39:19 +1100171 /* don't need to get the RCU readlock here - the process is dead and
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800172 * can't be modifying its own credentials. But shut RCU-lockdep up */
173 rcu_read_lock();
David Howellsc69e8d92008-11-14 10:39:19 +1100174 atomic_dec(&__task_cred(p)->user->processes);
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800175 rcu_read_unlock();
David Howellsc69e8d92008-11-14 10:39:19 +1100176
Pavel Emelyanov60347f62007-10-18 23:40:03 -0700177 proc_flush_task(p);
Ingo Molnar02030262009-05-17 11:24:08 +0200178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 write_lock_irq(&tasklist_lock);
Tejun Heoa288eec2011-06-17 16:50:37 +0200180 ptrace_release_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 __exit_signal(p);
Oleg Nesterov35f5cad2006-03-28 16:11:19 -0800182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 /*
184 * If we are the last non-leader member of the thread
185 * group, and the leader is zombie, then notify the
186 * group leader's parent process. (if it wants notification.)
187 */
188 zap_leader = 0;
189 leader = p->group_leader;
190 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 /*
192 * If we were the last child thread and the leader has
193 * exited already, and the leader's parent ignores SIGCHLD,
194 * then we are the one who should release the leader.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 */
Oleg Nesterov86773472011-06-22 23:09:09 +0200196 zap_leader = do_notify_parent(leader, leader->exit_signal);
Roland McGrathdae33572008-07-25 19:45:48 -0700197 if (zap_leader)
198 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 }
200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 write_unlock_irq(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 release_thread(p);
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800203 call_rcu(&p->rcu, delayed_put_task_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205 p = leader;
206 if (unlikely(zap_leader))
207 goto repeat;
208}
209
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210/*
211 * This checks not only the pgrp, but falls back on the pid if no
212 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
213 * without this...
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800214 *
215 * The caller must hold rcu lock or the tasklist lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 */
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800217struct pid *session_of_pgrp(struct pid *pgrp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
219 struct task_struct *p;
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800220 struct pid *sid = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800222 p = pid_task(pgrp, PIDTYPE_PGID);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800223 if (p == NULL)
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800224 p = pid_task(pgrp, PIDTYPE_PID);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800225 if (p != NULL)
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800226 sid = task_session(p);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 return sid;
229}
230
231/*
232 * Determine if a process group is "orphaned", according to the POSIX
233 * definition in 2.2.2.52. Orphaned process groups are not to be affected
234 * by terminal-generated stop signals. Newly orphaned process groups are
235 * to receive a SIGHUP and a SIGCONT.
236 *
237 * "I ask you, have you ever known what it is to be an orphan?"
238 */
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800239static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
241 struct task_struct *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800243 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300244 if ((p == ignored_task) ||
245 (p->exit_state && thread_group_empty(p)) ||
246 is_global_init(p->real_parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 continue;
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300248
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800249 if (task_pgrp(p->real_parent) != pgrp &&
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300250 task_session(p->real_parent) == task_session(p))
251 return 0;
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800252 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300253
254 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255}
256
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -0800257int is_current_pgrp_orphaned(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258{
259 int retval;
260
261 read_lock(&tasklist_lock);
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -0800262 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 read_unlock(&tasklist_lock);
264
265 return retval;
266}
267
Oleg Nesterov961c4672011-07-07 21:33:54 +0200268static bool has_stopped_jobs(struct pid *pgrp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 struct task_struct *p;
271
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800272 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
Oleg Nesterov961c4672011-07-07 21:33:54 +0200273 if (p->signal->flags & SIGNAL_STOP_STOPPED)
274 return true;
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800275 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
Oleg Nesterov961c4672011-07-07 21:33:54 +0200276
277 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278}
279
Oleg Nesterovf49ee502008-03-02 21:44:40 +0300280/*
281 * Check to see if any process groups have become orphaned as
282 * a result of our exiting, and if they have any stopped jobs,
283 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
284 */
285static void
286kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
287{
288 struct pid *pgrp = task_pgrp(tsk);
289 struct task_struct *ignored_task = tsk;
290
291 if (!parent)
292 /* exit: our father is in a different pgrp than
293 * we are and we were the only connection outside.
294 */
295 parent = tsk->real_parent;
296 else
297 /* reparent: our child is in a different pgrp than
298 * we are, and it was the only connection outside.
299 */
300 ignored_task = NULL;
301
302 if (task_pgrp(parent) != pgrp &&
303 task_session(parent) == task_session(tsk) &&
304 will_become_orphaned_pgrp(pgrp, ignored_task) &&
305 has_stopped_jobs(pgrp)) {
306 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
307 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
308 }
309}
310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311/**
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700312 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 *
314 * If a kernel thread is launched as a result of a system call, or if
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700315 * it ever exits, it should generally reparent itself to kthreadd so it
316 * isn't in the way of other processes and is correctly cleaned up on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 *
318 * The various task state such as scheduling policy and priority may have
319 * been inherited from a user process, so we reset them to sane values here.
320 *
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700321 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 */
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700323static void reparent_to_kthreadd(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324{
325 write_lock_irq(&tasklist_lock);
326
327 ptrace_unlink(current);
328 /* Reparent to init */
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700329 current->real_parent = current->parent = kthreadd_task;
Roland McGrathf4700212008-03-24 18:36:23 -0700330 list_move_tail(&current->sibling, &current->real_parent->children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
332 /* Set the exit signal to SIGCHLD so we signal init on exit */
333 current->exit_signal = SIGCHLD;
334
Ingo Molnare05606d2007-07-09 18:51:59 +0200335 if (task_nice(current) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 set_user_nice(current, 0);
337 /* cpus_allowed? */
338 /* rt_priority? */
339 /* signals? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 memcpy(current->signal->rlim, init_task.signal->rlim,
341 sizeof(current->signal->rlim));
David Howellsd84f4f92008-11-14 10:39:23 +1100342
343 atomic_inc(&init_cred.usage);
344 commit_creds(&init_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 write_unlock_irq(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800348void __set_special_pids(struct pid *pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349{
Oren Laadane19f2472006-01-08 01:03:58 -0800350 struct task_struct *curr = current->group_leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
Christian Borntraeger0d0df592009-10-26 16:49:34 -0700352 if (task_session(curr) != pid)
Oleg Nesterov7d8da092008-04-30 00:54:27 -0700353 change_pid(curr, PIDTYPE_SID, pid);
Oleg Nesterov1b0f7ff2009-04-02 16:58:39 -0700354
355 if (task_pgrp(curr) != pid)
Oleg Nesterov7d8da092008-04-30 00:54:27 -0700356 change_pid(curr, PIDTYPE_PGID, pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357}
358
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800359static void set_special_pids(struct pid *pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360{
361 write_lock_irq(&tasklist_lock);
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800362 __set_special_pids(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 write_unlock_irq(&tasklist_lock);
364}
365
366/*
Oleg Nesterov87245132009-06-17 16:27:23 -0700367 * Let kernel threads use this to say that they allow a certain signal.
368 * Must not be used if kthread was cloned with CLONE_SIGHAND.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 */
370int allow_signal(int sig)
371{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700372 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 return -EINVAL;
374
375 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov87245132009-06-17 16:27:23 -0700376 /* This is only needed for daemonize()'ed kthreads */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 sigdelset(&current->blocked, sig);
Oleg Nesterov87245132009-06-17 16:27:23 -0700378 /*
379 * Kernel threads handle their own signals. Let the signal code
380 * know it'll be handled, so that they don't get converted to
381 * SIGKILL or just silently dropped.
382 */
383 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 recalc_sigpending();
385 spin_unlock_irq(&current->sighand->siglock);
386 return 0;
387}
388
389EXPORT_SYMBOL(allow_signal);
390
391int disallow_signal(int sig)
392{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700393 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 return -EINVAL;
395
396 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov10ab8252007-05-09 02:34:37 -0700397 current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 recalc_sigpending();
399 spin_unlock_irq(&current->sighand->siglock);
400 return 0;
401}
402
403EXPORT_SYMBOL(disallow_signal);
404
405/*
406 * Put all the gunge required to become a kernel thread without
407 * attached user resources in one place where it belongs.
408 */
409
410void daemonize(const char *name, ...)
411{
412 va_list args;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 sigset_t blocked;
414
415 va_start(args, name);
416 vsnprintf(current->comm, sizeof(current->comm), name, args);
417 va_end(args);
418
419 /*
420 * If we were started as result of loading a module, close all of the
421 * user space pages. We don't need them, and if we didn't close them
422 * they would be locked into memory.
423 */
424 exit_mm(current);
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700425 /*
426 * We don't want to have TIF_FREEZE set if the system-wide hibernation
427 * or suspend transition begins right now.
428 */
Oleg Nesterov7b34e422008-07-25 01:47:37 -0700429 current->flags |= (PF_NOFREEZE | PF_KTHREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800431 if (current->nsproxy != &init_nsproxy) {
432 get_nsproxy(&init_nsproxy);
433 switch_task_namespaces(current, &init_nsproxy);
434 }
Oleg Nesterov297bd422008-02-08 04:19:10 -0800435 set_special_pids(&init_struct_pid);
Peter Zijlstra24ec8392006-12-08 02:36:04 -0800436 proc_clear_tty(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437
438 /* Block and flush all signals */
439 sigfillset(&blocked);
440 sigprocmask(SIG_BLOCK, &blocked, NULL);
441 flush_signals(current);
442
443 /* Become as one with the init task */
444
Al Viro3e93cd62009-03-29 19:00:13 -0400445 daemonize_fs_struct();
Daniel Walkerd4c5e412007-10-18 23:39:59 -0700446 exit_files(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 current->files = init_task.files;
448 atomic_inc(&current->files->count);
449
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700450 reparent_to_kthreadd();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451}
452
453EXPORT_SYMBOL(daemonize);
454
Arjan van de Ven858119e2006-01-14 13:20:43 -0800455static void close_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456{
457 int i, j;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700458 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459
460 j = 0;
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700461
462 /*
463 * It is safe to dereference the fd table without RCU or
464 * ->file_lock because this is the last reference to the
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800465 * files structure. But use RCU to shut RCU-lockdep up.
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700466 */
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800467 rcu_read_lock();
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700468 fdt = files_fdtable(files);
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800469 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 for (;;) {
471 unsigned long set;
472 i = j * __NFDBITS;
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800473 if (i >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700475 set = fdt->open_fds->fds_bits[j++];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 while (set) {
477 if (set & 1) {
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700478 struct file * file = xchg(&fdt->fd[i], NULL);
Ingo Molnar944be0b2007-02-12 00:52:26 -0800479 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 filp_close(file, files);
Ingo Molnar944be0b2007-02-12 00:52:26 -0800481 cond_resched();
482 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 }
484 i++;
485 set >>= 1;
486 }
487 }
488}
489
490struct files_struct *get_files_struct(struct task_struct *task)
491{
492 struct files_struct *files;
493
494 task_lock(task);
495 files = task->files;
496 if (files)
497 atomic_inc(&files->count);
498 task_unlock(task);
499
500 return files;
501}
502
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -0800503void put_files_struct(struct files_struct *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504{
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700505 struct fdtable *fdt;
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 if (atomic_dec_and_test(&files->count)) {
508 close_files(files);
509 /*
510 * Free the fd and fdset arrays if we expanded them.
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700511 * If the fdtable was embedded, pass files for freeing
512 * at the end of the RCU grace period. Otherwise,
513 * you can free files immediately.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 */
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800515 rcu_read_lock();
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700516 fdt = files_fdtable(files);
Vadim Lobanov4fd45812006-12-10 02:21:17 -0800517 if (fdt != &files->fdtab)
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700518 kmem_cache_free(files_cachep, files);
Vadim Lobanov01b2d932006-12-22 01:10:43 -0800519 free_fdtable(fdt);
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800520 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 }
522}
523
Al Viro3b125382008-04-22 05:31:30 -0400524void reset_files_struct(struct files_struct *files)
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700525{
Al Viro3b125382008-04-22 05:31:30 -0400526 struct task_struct *tsk = current;
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700527 struct files_struct *old;
528
529 old = tsk->files;
530 task_lock(tsk);
531 tsk->files = files;
532 task_unlock(tsk);
533 put_files_struct(old);
534}
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700535
Al Viro1ec7f1d2008-04-22 05:35:42 -0400536void exit_files(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537{
538 struct files_struct * files = tsk->files;
539
540 if (files) {
541 task_lock(tsk);
542 tsk->files = NULL;
543 task_unlock(tsk);
544 put_files_struct(files);
545 }
546}
547
Balbir Singhcf475ad2008-04-29 01:00:16 -0700548#ifdef CONFIG_MM_OWNER
549/*
KAMEZAWA Hiroyuki733eda72011-06-15 15:08:43 -0700550 * A task is exiting. If it owned this mm, find a new owner for the mm.
Balbir Singhcf475ad2008-04-29 01:00:16 -0700551 */
Balbir Singhcf475ad2008-04-29 01:00:16 -0700552void mm_update_next_owner(struct mm_struct *mm)
553{
554 struct task_struct *c, *g, *p = current;
555
556retry:
KAMEZAWA Hiroyuki733eda72011-06-15 15:08:43 -0700557 /*
558 * If the exiting or execing task is not the owner, it's
559 * someone else's problem.
560 */
561 if (mm->owner != p)
Balbir Singhcf475ad2008-04-29 01:00:16 -0700562 return;
KAMEZAWA Hiroyuki733eda72011-06-15 15:08:43 -0700563 /*
564 * The current owner is exiting/execing and there are no other
565 * candidates. Do not leave the mm pointing to a possibly
566 * freed task structure.
567 */
568 if (atomic_read(&mm->mm_users) <= 1) {
569 mm->owner = NULL;
570 return;
571 }
Balbir Singhcf475ad2008-04-29 01:00:16 -0700572
573 read_lock(&tasklist_lock);
574 /*
575 * Search in the children
576 */
577 list_for_each_entry(c, &p->children, sibling) {
578 if (c->mm == mm)
579 goto assign_new_owner;
580 }
581
582 /*
583 * Search in the siblings
584 */
Oleg Nesterovdea33cf2009-06-17 16:27:29 -0700585 list_for_each_entry(c, &p->real_parent->children, sibling) {
Balbir Singhcf475ad2008-04-29 01:00:16 -0700586 if (c->mm == mm)
587 goto assign_new_owner;
588 }
589
590 /*
591 * Search through everything else. We should not get
592 * here often
593 */
594 do_each_thread(g, c) {
595 if (c->mm == mm)
596 goto assign_new_owner;
597 } while_each_thread(g, c);
598
599 read_unlock(&tasklist_lock);
Balbir Singh31a78f22008-09-28 23:09:31 +0100600 /*
601 * We found no owner yet mm_users > 1: this implies that we are
602 * most likely racing with swapoff (try_to_unuse()) or /proc or
Hugh Dickinse5991372009-01-06 14:39:22 -0800603 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
Balbir Singh31a78f22008-09-28 23:09:31 +0100604 */
Balbir Singh31a78f22008-09-28 23:09:31 +0100605 mm->owner = NULL;
Balbir Singhcf475ad2008-04-29 01:00:16 -0700606 return;
607
608assign_new_owner:
609 BUG_ON(c == p);
610 get_task_struct(c);
611 /*
612 * The task_lock protects c->mm from changing.
613 * We always want mm->owner->mm == mm
614 */
615 task_lock(c);
Hugh Dickinse5991372009-01-06 14:39:22 -0800616 /*
617 * Delay read_unlock() till we have the task_lock()
618 * to ensure that c does not slip away underneath us
619 */
620 read_unlock(&tasklist_lock);
Balbir Singhcf475ad2008-04-29 01:00:16 -0700621 if (c->mm != mm) {
622 task_unlock(c);
623 put_task_struct(c);
624 goto retry;
625 }
Balbir Singhcf475ad2008-04-29 01:00:16 -0700626 mm->owner = c;
627 task_unlock(c);
628 put_task_struct(c);
629}
630#endif /* CONFIG_MM_OWNER */
631
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632/*
633 * Turn us into a lazy TLB process if we
634 * aren't already..
635 */
Adrian Bunk408b6642005-05-01 08:59:29 -0700636static void exit_mm(struct task_struct * tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637{
638 struct mm_struct *mm = tsk->mm;
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700639 struct core_state *core_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640
641 mm_release(tsk, mm);
642 if (!mm)
643 return;
644 /*
645 * Serialize with any possible pending coredump.
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700646 * We must hold mmap_sem around checking core_state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 * and clearing tsk->mm. The core-inducing thread
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700648 * will increment ->nr_threads for each thread in the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 * group with ->mm != NULL.
650 */
651 down_read(&mm->mmap_sem);
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700652 core_state = mm->core_state;
653 if (core_state) {
654 struct core_thread self;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 up_read(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700657 self.task = tsk;
658 self.next = xchg(&core_state->dumper.next, &self);
659 /*
660 * Implies mb(), the result of xchg() must be visible
661 * to core_state->dumper.
662 */
663 if (atomic_dec_and_test(&core_state->nr_threads))
664 complete(&core_state->startup);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
Oleg Nesterova94e2d42008-07-25 01:47:46 -0700666 for (;;) {
667 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
668 if (!self.task) /* see coredump_finish() */
669 break;
670 schedule();
671 }
672 __set_task_state(tsk, TASK_RUNNING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 down_read(&mm->mmap_sem);
674 }
675 atomic_inc(&mm->mm_count);
Eric Sesterhenn125e1872006-06-23 02:06:06 -0700676 BUG_ON(mm != tsk->active_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 /* more a memory barrier than a real lock */
678 task_lock(tsk);
679 tsk->mm = NULL;
680 up_read(&mm->mmap_sem);
681 enter_lazy_tlb(mm, current);
Rafael J. Wysocki0c1eecf2007-07-19 01:47:33 -0700682 /* We don't want this task to be frozen prematurely */
683 clear_freeze_flag(tsk);
Ying Han3d5992d2010-10-26 14:21:23 -0700684 if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
685 atomic_dec(&mm->oom_disable_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 task_unlock(tsk);
Balbir Singhcf475ad2008-04-29 01:00:16 -0700687 mm_update_next_owner(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 mmput(mm);
689}
690
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691/*
692 * When we die, we re-parent all our children.
693 * Try to give them to another thread in our thread
694 * group, and if no such member exists, give it to
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -0800695 * the child reaper process (ie "init") in our pid
696 * space.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 */
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700698static struct task_struct *find_new_reaper(struct task_struct *father)
Namhyung Kimd16e15f2010-10-27 15:34:10 -0700699 __releases(&tasklist_lock)
700 __acquires(&tasklist_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701{
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700702 struct pid_namespace *pid_ns = task_active_pid_ns(father);
703 struct task_struct *thread;
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700704
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700705 thread = father;
706 while_each_thread(father, thread) {
707 if (thread->flags & PF_EXITING)
708 continue;
709 if (unlikely(pid_ns->child_reaper == father))
710 pid_ns->child_reaper = thread;
711 return thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 }
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700713
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700714 if (unlikely(pid_ns->child_reaper == father)) {
715 write_unlock_irq(&tasklist_lock);
716 if (unlikely(pid_ns == &init_pid_ns))
717 panic("Attempted to kill init!");
718
719 zap_pid_ns_processes(pid_ns);
720 write_lock_irq(&tasklist_lock);
721 /*
722 * We can not clear ->child_reaper or leave it alone.
723 * There may by stealth EXIT_DEAD tasks on ->children,
724 * forget_original_parent() must move them somewhere.
725 */
726 pid_ns->child_reaper = init_pid_ns.child_reaper;
727 }
728
729 return pid_ns->child_reaper;
730}
731
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700732/*
733* Any that need to be release_task'd are put on the @dead list.
734 */
Oleg Nesterov9cd80bb2009-12-17 15:27:15 -0800735static void reparent_leader(struct task_struct *father, struct task_struct *p,
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700736 struct list_head *dead)
737{
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700738 list_move_tail(&p->sibling, &p->real_parent->children);
739
Oleg Nesterov0976a032011-06-22 23:09:39 +0200740 if (p->exit_state == EXIT_DEAD)
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700741 return;
742 /*
743 * If this is a threaded reparent there is no need to
744 * notify anyone anything has happened.
745 */
746 if (same_thread_group(p->real_parent, father))
747 return;
748
749 /* We don't want people slaying init. */
750 p->exit_signal = SIGCHLD;
751
752 /* If it has exited notify the new parent about this child's death. */
Tejun Heod21142e2011-06-17 16:50:34 +0200753 if (!p->ptrace &&
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700754 p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
Oleg Nesterov86773472011-06-22 23:09:09 +0200755 if (do_notify_parent(p, p->exit_signal)) {
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700756 p->exit_state = EXIT_DEAD;
757 list_move_tail(&p->sibling, dead);
758 }
759 }
760
761 kill_orphaned_pgrp(p, father);
762}
763
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764static void forget_original_parent(struct task_struct *father)
765{
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700766 struct task_struct *p, *n, *reaper;
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700767 LIST_HEAD(dead_children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
769 write_lock_irq(&tasklist_lock);
Oleg Nesterovc7e49c12010-08-10 18:03:07 -0700770 /*
771 * Note that exit_ptrace() and find_new_reaper() might
772 * drop tasklist_lock and reacquire it.
773 */
774 exit_ptrace(father);
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700775 reaper = find_new_reaper(father);
Roland McGrathf4700212008-03-24 18:36:23 -0700776
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 list_for_each_entry_safe(p, n, &father->children, sibling) {
Oleg Nesterov9cd80bb2009-12-17 15:27:15 -0800778 struct task_struct *t = p;
779 do {
780 t->real_parent = reaper;
781 if (t->parent == father) {
Tejun Heod21142e2011-06-17 16:50:34 +0200782 BUG_ON(t->ptrace);
Oleg Nesterov9cd80bb2009-12-17 15:27:15 -0800783 t->parent = t->real_parent;
784 }
785 if (t->pdeath_signal)
786 group_send_sig_info(t->pdeath_signal,
787 SEND_SIG_NOINFO, t);
788 } while_each_thread(p, t);
789 reparent_leader(father, p, &dead_children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 }
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700791 write_unlock_irq(&tasklist_lock);
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700792
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700793 BUG_ON(!list_empty(&father->children));
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700794
Oleg Nesterov5dfc80b2009-04-02 16:58:19 -0700795 list_for_each_entry_safe(p, n, &dead_children, sibling) {
796 list_del_init(&p->sibling);
Oleg Nesterov39c626a2009-04-02 16:58:18 -0700797 release_task(p);
798 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799}
800
801/*
802 * Send signals to all our closest relatives so that they know
803 * to properly mourn us..
804 */
Oleg Nesterov821c7de2008-03-02 21:44:44 +0300805static void exit_notify(struct task_struct *tsk, int group_dead)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806{
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +0200807 bool autoreap;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 /*
810 * This does two things:
811 *
812 * A. Make init inherit all the child processes
813 * B. Check to see if any process groups have become orphaned
814 * as a result of our exiting, and if they have any stopped
815 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
816 */
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700817 forget_original_parent(tsk);
Pavel Emelyanov2e4a7072007-10-18 23:40:01 -0700818 exit_task_namespaces(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700820 write_lock_irq(&tasklist_lock);
Oleg Nesterov821c7de2008-03-02 21:44:44 +0300821 if (group_dead)
822 kill_orphaned_pgrp(tsk->group_leader, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823
Oleg Nesterov24728442007-08-04 01:04:41 +0400824 /* Let father know we died
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 *
826 * Thread signals are configurable, but you aren't going to use
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300827 * that to send signals to arbitrary processes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 * That stops right now.
829 *
830 * If the parent exec id doesn't match the exec id we saved
831 * when we started then we know the parent has changed security
832 * domain.
833 *
834 * If our self_exec id doesn't match our parent_exec_id then
835 * we have changed execution domain as these two values started
836 * the same after a fork.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 */
Oleg Nesterov45cdf5c2011-06-23 19:06:50 +0200838 if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD &&
Oleg Nesterovf49ee502008-03-02 21:44:40 +0300839 (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
Oleg Nesterov432870d2009-04-06 16:16:02 +0200840 tsk->self_exec_id != tsk->parent_exec_id))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 tsk->exit_signal = SIGCHLD;
842
Oleg Nesterov45cdf5c2011-06-23 19:06:50 +0200843 if (unlikely(tsk->ptrace)) {
844 int sig = thread_group_leader(tsk) &&
845 thread_group_empty(tsk) &&
846 !ptrace_reparented(tsk) ?
847 tsk->exit_signal : SIGCHLD;
848 autoreap = do_notify_parent(tsk, sig);
849 } else if (thread_group_leader(tsk)) {
850 autoreap = thread_group_empty(tsk) &&
851 do_notify_parent(tsk, tsk->exit_signal);
852 } else {
853 autoreap = true;
854 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +0200856 tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857
Oleg Nesterov9c339162010-05-26 14:43:10 -0700858 /* mt-exec, de_thread() is waiting for group leader */
859 if (unlikely(tsk->signal->notify_count < 0))
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700860 wake_up_process(tsk->signal->group_exit_task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 write_unlock_irq(&tasklist_lock);
862
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 /* If the process is dead, release it - nobody will wait for it */
Oleg Nesterov53c8f9f2011-06-22 23:08:18 +0200864 if (autoreap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 release_task(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866}
867
Jeff Dikee18eecb2007-07-15 23:38:48 -0700868#ifdef CONFIG_DEBUG_STACK_USAGE
869static void check_stack_usage(void)
870{
871 static DEFINE_SPINLOCK(low_water_lock);
872 static int lowest_to_date = THREAD_SIZE;
Jeff Dikee18eecb2007-07-15 23:38:48 -0700873 unsigned long free;
874
Eric Sandeen7c9f8862008-04-22 16:38:23 -0500875 free = stack_not_used(current);
Jeff Dikee18eecb2007-07-15 23:38:48 -0700876
877 if (free >= lowest_to_date)
878 return;
879
880 spin_lock(&low_water_lock);
881 if (free < lowest_to_date) {
882 printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
883 "left\n",
884 current->comm, free);
885 lowest_to_date = free;
886 }
887 spin_unlock(&low_water_lock);
888}
889#else
890static inline void check_stack_usage(void) {}
891#endif
892
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -0800893NORET_TYPE void do_exit(long code)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894{
895 struct task_struct *tsk = current;
896 int group_dead;
897
898 profile_task_exit(tsk);
899
Jens Axboe73c10102011-03-08 13:19:51 +0100900 WARN_ON(blk_needs_flush_plug(tsk));
Jens Axboe22e2c502005-06-27 10:55:12 +0200901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 if (unlikely(in_interrupt()))
903 panic("Aiee, killing interrupt handler!");
904 if (unlikely(!tsk->pid))
905 panic("Attempted to kill the idle task!");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
Nelson Elhage33dd94a2010-12-02 14:31:21 -0800907 /*
908 * If do_exit is called because this processes oopsed, it's possible
909 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
910 * continuing. Amongst other possible reasons, this is to prevent
911 * mm_release()->clear_child_tid() from writing to a user-controlled
912 * kernel address.
913 */
914 set_fs(USER_DS);
915
Tejun Heoa288eec2011-06-17 16:50:37 +0200916 ptrace_event(PTRACE_EVENT_EXIT, code);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
David Howellse0e81732009-09-02 09:13:40 +0100918 validate_creds_for_do_exit(tsk);
919
Alexander Nybergdf164db2005-06-23 00:09:13 -0700920 /*
921 * We're taking recursive faults here in do_exit. Safest is to just
922 * leave this task alone and wait for reboot.
923 */
924 if (unlikely(tsk->flags & PF_EXITING)) {
925 printk(KERN_ALERT
926 "Fixing recursive fault but reboot is needed!\n");
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -0700927 /*
928 * We can do this unlocked here. The futex code uses
929 * this flag just to verify whether the pi state
930 * cleanup has been done or not. In the worst case it
931 * loops once more. We pretend that the cleanup was
932 * done as there is no way to return. Either the
933 * OWNER_DIED bit is set by now or we push the blocked
934 * task into the wait for ever nirwana as well.
935 */
936 tsk->flags |= PF_EXITPIDONE;
Alexander Nybergdf164db2005-06-23 00:09:13 -0700937 set_current_state(TASK_UNINTERRUPTIBLE);
938 schedule();
939 }
940
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100941 exit_irq_thread();
942
Oleg Nesterovd12619b2008-02-08 04:19:12 -0800943 exit_signals(tsk); /* sets PF_EXITING */
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -0700944 /*
945 * tsk->flags are checked in the futex code to protect against
946 * an exiting task cleaning up the robust pi futexes.
947 */
Oleg Nesterovd2ee7192007-10-16 23:26:47 -0700948 smp_mb();
Thomas Gleixner1d615482009-11-17 14:54:03 +0100949 raw_spin_unlock_wait(&tsk->pi_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 if (unlikely(in_atomic()))
952 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700953 current->comm, task_pid_nr(current),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 preempt_count());
955
956 acct_update_integrals(tsk);
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -0800957 /* sync mm's RSS info before statistics gathering */
KAMEZAWA Hiroyukia3a2e762010-04-06 14:34:42 -0700958 if (tsk->mm)
959 sync_mm_rss(tsk, tsk->mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 group_dead = atomic_dec_and_test(&tsk->signal->live);
Andrew Mortonc3068952005-08-04 16:49:32 -0700961 if (group_dead) {
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -0700962 hrtimer_cancel(&tsk->signal->real_timer);
Roland McGrath25f407f2005-10-21 15:03:29 -0700963 exit_itimers(tsk->signal);
Jiri Pirko1f102062009-09-22 16:44:10 -0700964 if (tsk->mm)
965 setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
Andrew Mortonc3068952005-08-04 16:49:32 -0700966 }
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700967 acct_collect(code, group_dead);
Miloslav Trmac522ed772007-07-15 23:40:56 -0700968 if (group_dead)
969 tty_audit_exit();
Al Virofa84cb92006-03-29 20:30:19 -0500970 if (unlikely(tsk->audit_context))
971 audit_free(tsk);
Oleg Nesterov115085e2006-12-06 20:36:51 -0800972
Jonathan Limf2ab6d82007-08-30 23:56:23 -0700973 tsk->exit_code = code;
Oleg Nesterov115085e2006-12-06 20:36:51 -0800974 taskstats_exit(tsk, group_dead);
Shailabh Nagarc7572492006-07-14 00:24:40 -0700975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 exit_mm(tsk);
977
KaiGai Kohei0e464812006-06-25 05:49:24 -0700978 if (group_dead)
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700979 acct_process();
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -0400980 trace_sched_process_exit(tsk);
981
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 exit_sem(tsk);
Al Viro1ec7f1d2008-04-22 05:35:42 -0400983 exit_files(tsk);
984 exit_fs(tsk);
Jeff Dikee18eecb2007-07-15 23:38:48 -0700985 check_stack_usage();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 exit_thread();
Stephane Eranian0b3fcf12011-01-03 18:20:01 +0200987
988 /*
989 * Flush inherited counters to the parent - before the parent
990 * gets woken up by child-exit notifications.
991 *
992 * because of cgroup mode, must be called before cgroup_exit()
993 */
994 perf_event_exit_task(tsk);
995
Paul Menageb4f48b62007-10-18 23:39:33 -0700996 cgroup_exit(tsk, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997
Alan Cox5ec93d12009-11-30 13:18:45 +0000998 if (group_dead)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 disassociate_ctty(1);
1000
Al Viroa1261f52005-11-13 16:06:55 -08001001 module_put(task_thread_info(tsk)->exec_domain->module);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002
Matt Helsley9f460802005-11-07 00:59:16 -08001003 proc_exit_connector(tsk);
Ingo Molnar33b2fb32009-05-17 11:08:41 +02001004
1005 /*
Frederic Weisbecker24f1e32c2009-09-09 19:22:48 +02001006 * FIXME: do that only when needed, using sched_exit tracepoint
1007 */
Frederic Weisbeckerbf26c012011-04-07 16:53:20 +02001008 ptrace_put_breakpoints(tsk);
Ingo Molnar33b2fb32009-05-17 11:08:41 +02001009
Oleg Nesterov821c7de2008-03-02 21:44:44 +03001010 exit_notify(tsk, group_dead);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011#ifdef CONFIG_NUMA
Miao Xiec0ff7452010-05-24 14:32:08 -07001012 task_lock(tsk);
Lee Schermerhornf0be3d32008-04-28 02:13:08 -07001013 mpol_put(tsk->mempolicy);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 tsk->mempolicy = NULL;
Miao Xiec0ff7452010-05-24 14:32:08 -07001015 task_unlock(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016#endif
Alexey Dobriyan42b2dd02007-10-16 23:27:30 -07001017#ifdef CONFIG_FUTEX
Ingo Molnarc87e2832006-06-27 02:54:58 -07001018 if (unlikely(current->pi_state_cache))
1019 kfree(current->pi_state_cache);
Alexey Dobriyan42b2dd02007-10-16 23:27:30 -07001020#endif
Ingo Molnarc87e2832006-06-27 02:54:58 -07001021 /*
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07001022 * Make sure we are holding no locks:
Ingo Molnarde5097c2006-01-09 15:59:21 -08001023 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07001024 debug_check_no_locks_held(tsk);
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -07001025 /*
1026 * We can do this unlocked here. The futex code uses this flag
1027 * just to verify whether the pi state cleanup has been done
1028 * or not. In the worst case it loops once more.
1029 */
1030 tsk->flags |= PF_EXITPIDONE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031
Al Viroafc847b2006-02-28 12:51:55 -05001032 if (tsk->io_context)
Louis Rillingb69f2292009-12-04 14:52:42 +01001033 exit_io_context(tsk);
Al Viroafc847b2006-02-28 12:51:55 -05001034
Jens Axboeb92ce552006-04-11 13:52:07 +02001035 if (tsk->splice_pipe)
1036 __free_pipe_info(tsk->splice_pipe);
1037
David Howellse0e81732009-09-02 09:13:40 +01001038 validate_creds_for_do_exit(tsk);
1039
Coywolf Qi Hunt74072512005-10-30 15:02:47 -08001040 preempt_disable();
Paul E. McKenneyf41d9112009-08-22 13:56:52 -07001041 exit_rcu();
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001042 /* causes final put_task_struct in finish_task_switch(). */
Oleg Nesterovc394cc92006-09-29 02:01:11 -07001043 tsk->state = TASK_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 schedule();
1045 BUG();
1046 /* Avoid "noreturn function does return". */
Alan Cox54306cf2006-09-29 02:00:42 -07001047 for (;;)
1048 cpu_relax(); /* For when BUG is null */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049}
1050
Russ Anderson012914d2005-04-23 00:08:00 -07001051EXPORT_SYMBOL_GPL(do_exit);
1052
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1054{
1055 if (comp)
1056 complete(comp);
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001057
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 do_exit(code);
1059}
1060
1061EXPORT_SYMBOL(complete_and_exit);
1062
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001063SYSCALL_DEFINE1(exit, int, error_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064{
1065 do_exit((error_code&0xff)<<8);
1066}
1067
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068/*
1069 * Take down every thread in the group. This is called by fatal signals
1070 * as well as by sys_exit_group (below).
1071 */
1072NORET_TYPE void
1073do_group_exit(int exit_code)
1074{
Oleg Nesterovbfc4b082008-04-30 00:52:36 -07001075 struct signal_struct *sig = current->signal;
1076
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1078
Oleg Nesterovbfc4b082008-04-30 00:52:36 -07001079 if (signal_group_exit(sig))
1080 exit_code = sig->group_exit_code;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 else if (!thread_group_empty(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 struct sighand_struct *const sighand = current->sighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 spin_lock_irq(&sighand->siglock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001084 if (signal_group_exit(sig))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 /* Another thread got here before we took the lock. */
1086 exit_code = sig->group_exit_code;
1087 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 sig->group_exit_code = exit_code;
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001089 sig->flags = SIGNAL_GROUP_EXIT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 zap_other_threads(current);
1091 }
1092 spin_unlock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 }
1094
1095 do_exit(exit_code);
1096 /* NOTREACHED */
1097}
1098
1099/*
1100 * this kills every thread in the thread group. Note that any externally
1101 * wait4()-ing process will get the correct exit code - even if this
1102 * thread is not the thread group leader.
1103 */
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001104SYSCALL_DEFINE1(exit_group, int, error_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105{
1106 do_group_exit((error_code & 0xff) << 8);
Heiko Carstens2ed7c032009-01-14 14:13:54 +01001107 /* NOTREACHED */
1108 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109}
1110
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001111struct wait_opts {
1112 enum pid_type wo_type;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001113 int wo_flags;
Richard Kennedye1eb1eb2009-06-17 16:27:42 -07001114 struct pid *wo_pid;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001115
1116 struct siginfo __user *wo_info;
1117 int __user *wo_stat;
1118 struct rusage __user *wo_rusage;
1119
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001120 wait_queue_t child_wait;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001121 int notask_error;
1122};
1123
Oleg Nesterov989264f2009-09-23 15:56:49 -07001124static inline
1125struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
Eric W. Biederman161550d2008-02-08 04:19:14 -08001126{
Oleg Nesterov989264f2009-09-23 15:56:49 -07001127 if (type != PIDTYPE_PID)
1128 task = task->group_leader;
1129 return task->pids[type].pid;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001130}
1131
Oleg Nesterov989264f2009-09-23 15:56:49 -07001132static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
Oleg Nesterov5c01ba42009-09-23 15:56:48 -07001133{
1134 return wo->wo_type == PIDTYPE_MAX ||
1135 task_pid_type(p, wo->wo_type) == wo->wo_pid;
1136}
1137
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001138static int eligible_child(struct wait_opts *wo, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139{
Oleg Nesterov5c01ba42009-09-23 15:56:48 -07001140 if (!eligible_pid(wo, p))
1141 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142 /* Wait for all children (clone and not) if __WALL is set;
1143 * otherwise, wait for clone children *only* if __WCLONE is
1144 * set; otherwise, wait for non-clone children *only*. (Note:
1145 * A "clone" child here is one that reports to its parent
1146 * using a signal other than SIGCHLD.) */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001147 if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
1148 && !(wo->wo_flags & __WALL))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150
Roland McGrath14dd0b82008-03-30 18:41:25 -07001151 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152}
1153
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001154static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
1155 pid_t pid, uid_t uid, int why, int status)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156{
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001157 struct siginfo __user *infop;
1158 int retval = wo->wo_rusage
1159 ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
Ingo Molnar36c8b582006-07-03 00:25:41 -07001160
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 put_task_struct(p);
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001162 infop = wo->wo_info;
Vitaly Mayatskikhb6fe2d12009-09-23 15:56:52 -07001163 if (infop) {
1164 if (!retval)
1165 retval = put_user(SIGCHLD, &infop->si_signo);
1166 if (!retval)
1167 retval = put_user(0, &infop->si_errno);
1168 if (!retval)
1169 retval = put_user((short)why, &infop->si_code);
1170 if (!retval)
1171 retval = put_user(pid, &infop->si_pid);
1172 if (!retval)
1173 retval = put_user(uid, &infop->si_uid);
1174 if (!retval)
1175 retval = put_user(status, &infop->si_status);
1176 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 if (!retval)
1178 retval = pid;
1179 return retval;
1180}
1181
1182/*
1183 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1184 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1185 * the lock and this task is uninteresting. If we return nonzero, we have
1186 * released the lock and the system call should return.
1187 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001188static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189{
1190 unsigned long state;
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001191 int retval, status, traced;
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001192 pid_t pid = task_pid_vnr(p);
David Howellsc69e8d92008-11-14 10:39:19 +11001193 uid_t uid = __task_cred(p)->uid;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001194 struct siginfo __user *infop;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001196 if (!likely(wo->wo_flags & WEXITED))
Roland McGrath98abed02008-03-19 19:24:59 -07001197 return 0;
1198
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001199 if (unlikely(wo->wo_flags & WNOWAIT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 int exit_code = p->exit_code;
Thiago Farinaf3abd4f2010-03-05 13:42:52 -08001201 int why;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 get_task_struct(p);
1204 read_unlock(&tasklist_lock);
1205 if ((exit_code & 0x7f) == 0) {
1206 why = CLD_EXITED;
1207 status = exit_code >> 8;
1208 } else {
1209 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1210 status = exit_code & 0x7f;
1211 }
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001212 return wait_noreap_copyout(wo, p, pid, uid, why, status);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 }
1214
1215 /*
1216 * Try to move the task's state to DEAD
1217 * only one thread is allowed to do this:
1218 */
1219 state = xchg(&p->exit_state, EXIT_DEAD);
1220 if (state != EXIT_ZOMBIE) {
1221 BUG_ON(state != EXIT_DEAD);
1222 return 0;
1223 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224
Oleg Nesterov53b6f9f2008-04-30 00:53:13 -07001225 traced = ptrace_reparented(p);
Oleg Nesterovbefca962009-06-18 16:49:11 -07001226 /*
1227 * It can be ptraced but not reparented, check
Oleg Nesterove550f142011-06-22 23:09:54 +02001228 * thread_group_leader() to filter out sub-threads.
Oleg Nesterovbefca962009-06-18 16:49:11 -07001229 */
Oleg Nesterove550f142011-06-22 23:09:54 +02001230 if (likely(!traced) && thread_group_leader(p)) {
Jesper Juhl3795e162006-01-09 20:54:39 -08001231 struct signal_struct *psig;
1232 struct signal_struct *sig;
Jiri Pirko1f102062009-09-22 16:44:10 -07001233 unsigned long maxrss;
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +09001234 cputime_t tgutime, tgstime;
Jesper Juhl3795e162006-01-09 20:54:39 -08001235
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 /*
1237 * The resource counters for the group leader are in its
1238 * own task_struct. Those for dead threads in the group
1239 * are in its signal_struct, as are those for the child
1240 * processes it has previously reaped. All these
1241 * accumulate in the parent's signal_struct c* fields.
1242 *
1243 * We don't bother to take a lock here to protect these
1244 * p->signal fields, because they are only touched by
1245 * __exit_signal, which runs with tasklist_lock
1246 * write-locked anyway, and so is excluded here. We do
Oleg Nesterovd1e98f42009-06-17 16:27:34 -07001247 * need to protect the access to parent->signal fields,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 * as other threads in the parent group can be right
1249 * here reaping other children at the same time.
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +09001250 *
1251 * We use thread_group_times() to get times for the thread
1252 * group, which consolidates times for all threads in the
1253 * group including the group leader.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 */
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +09001255 thread_group_times(p, &tgutime, &tgstime);
Oleg Nesterovd1e98f42009-06-17 16:27:34 -07001256 spin_lock_irq(&p->real_parent->sighand->siglock);
1257 psig = p->real_parent->signal;
Jesper Juhl3795e162006-01-09 20:54:39 -08001258 sig = p->signal;
1259 psig->cutime =
1260 cputime_add(psig->cutime,
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +09001261 cputime_add(tgutime,
1262 sig->cutime));
Jesper Juhl3795e162006-01-09 20:54:39 -08001263 psig->cstime =
1264 cputime_add(psig->cstime,
Hidetoshi Seto0cf55e12009-12-02 17:28:07 +09001265 cputime_add(tgstime,
1266 sig->cstime));
Laurent Vivier9ac52312007-10-15 17:00:19 +02001267 psig->cgtime =
1268 cputime_add(psig->cgtime,
1269 cputime_add(p->gtime,
1270 cputime_add(sig->gtime,
1271 sig->cgtime)));
Jesper Juhl3795e162006-01-09 20:54:39 -08001272 psig->cmin_flt +=
1273 p->min_flt + sig->min_flt + sig->cmin_flt;
1274 psig->cmaj_flt +=
1275 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1276 psig->cnvcsw +=
1277 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1278 psig->cnivcsw +=
1279 p->nivcsw + sig->nivcsw + sig->cnivcsw;
Eric Dumazet6eaeeab2007-05-10 22:22:37 -07001280 psig->cinblock +=
1281 task_io_get_inblock(p) +
1282 sig->inblock + sig->cinblock;
1283 psig->coublock +=
1284 task_io_get_oublock(p) +
1285 sig->oublock + sig->coublock;
Jiri Pirko1f102062009-09-22 16:44:10 -07001286 maxrss = max(sig->maxrss, sig->cmaxrss);
1287 if (psig->cmaxrss < maxrss)
1288 psig->cmaxrss = maxrss;
Andrea Righi59954772008-07-27 17:29:15 +02001289 task_io_accounting_add(&psig->ioac, &p->ioac);
1290 task_io_accounting_add(&psig->ioac, &sig->ioac);
Oleg Nesterovd1e98f42009-06-17 16:27:34 -07001291 spin_unlock_irq(&p->real_parent->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 }
1293
1294 /*
1295 * Now we are sure this task is interesting, and no other
1296 * thread can reap it because we set its state to EXIT_DEAD.
1297 */
1298 read_unlock(&tasklist_lock);
1299
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001300 retval = wo->wo_rusage
1301 ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1303 ? p->signal->group_exit_code : p->exit_code;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001304 if (!retval && wo->wo_stat)
1305 retval = put_user(status, wo->wo_stat);
1306
1307 infop = wo->wo_info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 if (!retval && infop)
1309 retval = put_user(SIGCHLD, &infop->si_signo);
1310 if (!retval && infop)
1311 retval = put_user(0, &infop->si_errno);
1312 if (!retval && infop) {
1313 int why;
1314
1315 if ((status & 0x7f) == 0) {
1316 why = CLD_EXITED;
1317 status >>= 8;
1318 } else {
1319 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1320 status &= 0x7f;
1321 }
1322 retval = put_user((short)why, &infop->si_code);
1323 if (!retval)
1324 retval = put_user(status, &infop->si_status);
1325 }
1326 if (!retval && infop)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001327 retval = put_user(pid, &infop->si_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 if (!retval && infop)
David Howellsc69e8d92008-11-14 10:39:19 +11001329 retval = put_user(uid, &infop->si_uid);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001330 if (!retval)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001331 retval = pid;
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001332
1333 if (traced) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 write_lock_irq(&tasklist_lock);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001335 /* We dropped tasklist, ptracer could die and untrace */
1336 ptrace_unlink(p);
1337 /*
Oleg Nesterov86773472011-06-22 23:09:09 +02001338 * If this is not a sub-thread, notify the parent.
1339 * If parent wants a zombie, don't release it now.
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001340 */
Oleg Nesterov86773472011-06-22 23:09:09 +02001341 if (thread_group_leader(p) &&
1342 !do_notify_parent(p, p->exit_signal)) {
1343 p->exit_state = EXIT_ZOMBIE;
1344 p = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345 }
1346 write_unlock_irq(&tasklist_lock);
1347 }
1348 if (p != NULL)
1349 release_task(p);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001350
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 return retval;
1352}
1353
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001354static int *task_stopped_code(struct task_struct *p, bool ptrace)
1355{
1356 if (ptrace) {
Tejun Heo544b2c92011-06-14 11:20:18 +02001357 if (task_is_stopped_or_traced(p) &&
1358 !(p->jobctl & JOBCTL_LISTENING))
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001359 return &p->exit_code;
1360 } else {
1361 if (p->signal->flags & SIGNAL_STOP_STOPPED)
1362 return &p->signal->group_exit_code;
1363 }
1364 return NULL;
1365}
1366
Tejun Heo19e27462011-05-12 10:47:23 +02001367/**
1368 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1369 * @wo: wait options
1370 * @ptrace: is the wait for ptrace
1371 * @p: task to wait for
1372 *
1373 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1374 *
1375 * CONTEXT:
1376 * read_lock(&tasklist_lock), which is released if return value is
1377 * non-zero. Also, grabs and releases @p->sighand->siglock.
1378 *
1379 * RETURNS:
1380 * 0 if wait condition didn't exist and search for other wait conditions
1381 * should continue. Non-zero return, -errno on failure and @p's pid on
1382 * success, implies that tasklist_lock is released and wait condition
1383 * search should terminate.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001385static int wait_task_stopped(struct wait_opts *wo,
1386 int ptrace, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387{
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001388 struct siginfo __user *infop;
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001389 int retval, exit_code, *p_code, why;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001390 uid_t uid = 0; /* unneeded, required by compiler */
Oleg Nesterovc8950782007-11-28 16:21:24 -08001391 pid_t pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392
Oleg Nesterov47918022009-06-17 16:27:39 -07001393 /*
1394 * Traditionally we see ptrace'd stopped tasks regardless of options.
1395 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001396 if (!ptrace && !(wo->wo_flags & WUNTRACED))
Roland McGrath98abed02008-03-19 19:24:59 -07001397 return 0;
1398
Tejun Heo19e27462011-05-12 10:47:23 +02001399 if (!task_stopped_code(p, ptrace))
1400 return 0;
1401
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001402 exit_code = 0;
1403 spin_lock_irq(&p->sighand->siglock);
1404
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001405 p_code = task_stopped_code(p, ptrace);
1406 if (unlikely(!p_code))
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001407 goto unlock_sig;
1408
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001409 exit_code = *p_code;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001410 if (!exit_code)
1411 goto unlock_sig;
1412
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001413 if (!unlikely(wo->wo_flags & WNOWAIT))
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001414 *p_code = 0;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001415
Daniel J Bluemanf362b732010-08-17 23:56:55 +01001416 uid = task_uid(p);
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001417unlock_sig:
1418 spin_unlock_irq(&p->sighand->siglock);
1419 if (!exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 return 0;
1421
1422 /*
1423 * Now we are pretty sure this task is interesting.
1424 * Make sure it doesn't get reaped out from under us while we
1425 * give up the lock and then examine it below. We don't want to
1426 * keep holding onto the tasklist_lock while we call getrusage and
1427 * possibly take page faults for user memory.
1428 */
1429 get_task_struct(p);
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001430 pid = task_pid_vnr(p);
Roland McGrathf4700212008-03-24 18:36:23 -07001431 why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432 read_unlock(&tasklist_lock);
1433
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001434 if (unlikely(wo->wo_flags & WNOWAIT))
1435 return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001437 retval = wo->wo_rusage
1438 ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
1439 if (!retval && wo->wo_stat)
1440 retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);
1441
1442 infop = wo->wo_info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 if (!retval && infop)
1444 retval = put_user(SIGCHLD, &infop->si_signo);
1445 if (!retval && infop)
1446 retval = put_user(0, &infop->si_errno);
1447 if (!retval && infop)
Roland McGrath6efcae42008-03-08 11:41:22 -08001448 retval = put_user((short)why, &infop->si_code);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 if (!retval && infop)
1450 retval = put_user(exit_code, &infop->si_status);
1451 if (!retval && infop)
Oleg Nesterovc8950782007-11-28 16:21:24 -08001452 retval = put_user(pid, &infop->si_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 if (!retval && infop)
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001454 retval = put_user(uid, &infop->si_uid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455 if (!retval)
Oleg Nesterovc8950782007-11-28 16:21:24 -08001456 retval = pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 put_task_struct(p);
1458
1459 BUG_ON(!retval);
1460 return retval;
1461}
1462
1463/*
1464 * Handle do_wait work for one task in a live, non-stopped state.
1465 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1466 * the lock and this task is uninteresting. If we return nonzero, we have
1467 * released the lock and the system call should return.
1468 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001469static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470{
1471 int retval;
1472 pid_t pid;
1473 uid_t uid;
1474
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001475 if (!unlikely(wo->wo_flags & WCONTINUED))
Roland McGrath98abed02008-03-19 19:24:59 -07001476 return 0;
1477
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1479 return 0;
1480
1481 spin_lock_irq(&p->sighand->siglock);
1482 /* Re-check with the lock held. */
1483 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1484 spin_unlock_irq(&p->sighand->siglock);
1485 return 0;
1486 }
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001487 if (!unlikely(wo->wo_flags & WNOWAIT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
Daniel J Bluemanf362b732010-08-17 23:56:55 +01001489 uid = task_uid(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 spin_unlock_irq(&p->sighand->siglock);
1491
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001492 pid = task_pid_vnr(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 get_task_struct(p);
1494 read_unlock(&tasklist_lock);
1495
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001496 if (!wo->wo_info) {
1497 retval = wo->wo_rusage
1498 ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499 put_task_struct(p);
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001500 if (!retval && wo->wo_stat)
1501 retval = put_user(0xffff, wo->wo_stat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 if (!retval)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001503 retval = pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 } else {
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001505 retval = wait_noreap_copyout(wo, p, pid, uid,
1506 CLD_CONTINUED, SIGCONT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507 BUG_ON(retval == 0);
1508 }
1509
1510 return retval;
1511}
1512
Roland McGrath98abed02008-03-19 19:24:59 -07001513/*
1514 * Consider @p for a wait by @parent.
1515 *
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001516 * -ECHILD should be in ->notask_error before the first call.
Roland McGrath98abed02008-03-19 19:24:59 -07001517 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1518 * Returns zero if the search for a child should continue;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001519 * then ->notask_error is 0 if @p is an eligible child,
Roland McGrath14dd0b82008-03-30 18:41:25 -07001520 * or another error from security_task_wait(), or still -ECHILD.
Roland McGrath98abed02008-03-19 19:24:59 -07001521 */
Oleg Nesterovb6e763f2009-09-23 15:56:50 -07001522static int wait_consider_task(struct wait_opts *wo, int ptrace,
1523 struct task_struct *p)
Roland McGrath98abed02008-03-19 19:24:59 -07001524{
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001525 int ret = eligible_child(wo, p);
Roland McGrath14dd0b82008-03-30 18:41:25 -07001526 if (!ret)
Roland McGrath98abed02008-03-19 19:24:59 -07001527 return ret;
1528
Oleg Nesterova2322e12009-09-23 15:56:45 -07001529 ret = security_task_wait(p);
Roland McGrath14dd0b82008-03-30 18:41:25 -07001530 if (unlikely(ret < 0)) {
1531 /*
1532 * If we have not yet seen any eligible child,
1533 * then let this error code replace -ECHILD.
1534 * A permission error will give the user a clue
1535 * to look for security policy problems, rather
1536 * than for mysterious wait bugs.
1537 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001538 if (wo->notask_error)
1539 wo->notask_error = ret;
Oleg Nesterov78a3d9d2009-04-29 18:01:23 +02001540 return 0;
Roland McGrath14dd0b82008-03-30 18:41:25 -07001541 }
1542
Tejun Heo823b0182011-03-23 10:37:01 +01001543 /* dead body doesn't have much to contribute */
Roland McGrath98abed02008-03-19 19:24:59 -07001544 if (p->exit_state == EXIT_DEAD)
1545 return 0;
1546
Tejun Heo9b84cca2011-03-23 10:37:01 +01001547 /* slay zombie? */
1548 if (p->exit_state == EXIT_ZOMBIE) {
Tejun Heo45cb24a2011-03-23 10:37:01 +01001549 /*
1550 * A zombie ptracee is only visible to its ptracer.
1551 * Notification and reaping will be cascaded to the real
1552 * parent when the ptracer detaches.
1553 */
Tejun Heod21142e2011-06-17 16:50:34 +02001554 if (likely(!ptrace) && unlikely(p->ptrace)) {
Tejun Heo45cb24a2011-03-23 10:37:01 +01001555 /* it will become visible, clear notask_error */
1556 wo->notask_error = 0;
1557 return 0;
1558 }
1559
Tejun Heo9b84cca2011-03-23 10:37:01 +01001560 /* we don't reap group leaders with subthreads */
1561 if (!delay_group_leader(p))
1562 return wait_task_zombie(wo, p);
Roland McGrath98abed02008-03-19 19:24:59 -07001563
Tejun Heo9b84cca2011-03-23 10:37:01 +01001564 /*
1565 * Allow access to stopped/continued state via zombie by
1566 * falling through. Clearing of notask_error is complex.
1567 *
1568 * When !@ptrace:
1569 *
1570 * If WEXITED is set, notask_error should naturally be
1571 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1572 * so, if there are live subthreads, there are events to
1573 * wait for. If all subthreads are dead, it's still safe
1574 * to clear - this function will be called again in finite
1575 * amount time once all the subthreads are released and
1576 * will then return without clearing.
1577 *
1578 * When @ptrace:
1579 *
1580 * Stopped state is per-task and thus can't change once the
1581 * target task dies. Only continued and exited can happen.
1582 * Clear notask_error if WCONTINUED | WEXITED.
1583 */
1584 if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
1585 wo->notask_error = 0;
1586 } else {
1587 /*
Tejun Heo45cb24a2011-03-23 10:37:01 +01001588 * If @p is ptraced by a task in its real parent's group,
1589 * hide group stop/continued state when looking at @p as
1590 * the real parent; otherwise, a single stop can be
1591 * reported twice as group and ptrace stops.
1592 *
1593 * If a ptracer wants to distinguish the two events for its
1594 * own children, it should create a separate process which
1595 * takes the role of real parent.
1596 */
Oleg Nesterov479bf982011-06-24 17:34:39 +02001597 if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))
Tejun Heo45cb24a2011-03-23 10:37:01 +01001598 return 0;
1599
1600 /*
Tejun Heo9b84cca2011-03-23 10:37:01 +01001601 * @p is alive and it's gonna stop, continue or exit, so
1602 * there always is something to wait for.
1603 */
1604 wo->notask_error = 0;
1605 }
Roland McGrath98abed02008-03-19 19:24:59 -07001606
1607 /*
Tejun Heo45cb24a2011-03-23 10:37:01 +01001608 * Wait for stopped. Depending on @ptrace, different stopped state
1609 * is used and the two don't interact with each other.
Roland McGrath98abed02008-03-19 19:24:59 -07001610 */
Tejun Heo19e27462011-05-12 10:47:23 +02001611 ret = wait_task_stopped(wo, ptrace, p);
1612 if (ret)
1613 return ret;
Roland McGrath98abed02008-03-19 19:24:59 -07001614
Tejun Heo45cb24a2011-03-23 10:37:01 +01001615 /*
1616 * Wait for continued. There's only one continued state and the
1617 * ptracer can consume it which can confuse the real parent. Don't
1618 * use WCONTINUED from ptracer. You don't need or want it.
1619 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001620 return wait_task_continued(wo, p);
Roland McGrath98abed02008-03-19 19:24:59 -07001621}
1622
1623/*
1624 * Do the work of do_wait() for one thread in the group, @tsk.
1625 *
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001626 * -ECHILD should be in ->notask_error before the first call.
Roland McGrath98abed02008-03-19 19:24:59 -07001627 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1628 * Returns zero if the search for a child should continue; then
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001629 * ->notask_error is 0 if there were any eligible children,
Roland McGrath14dd0b82008-03-30 18:41:25 -07001630 * or another error from security_task_wait(), or still -ECHILD.
Roland McGrath98abed02008-03-19 19:24:59 -07001631 */
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001632static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
Roland McGrath98abed02008-03-19 19:24:59 -07001633{
1634 struct task_struct *p;
1635
1636 list_for_each_entry(p, &tsk->children, sibling) {
Oleg Nesterov9cd80bb2009-12-17 15:27:15 -08001637 int ret = wait_consider_task(wo, 0, p);
1638 if (ret)
1639 return ret;
Roland McGrath98abed02008-03-19 19:24:59 -07001640 }
1641
1642 return 0;
1643}
1644
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001645static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
Roland McGrath98abed02008-03-19 19:24:59 -07001646{
1647 struct task_struct *p;
1648
Roland McGrathf4700212008-03-24 18:36:23 -07001649 list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
Oleg Nesterovb6e763f2009-09-23 15:56:50 -07001650 int ret = wait_consider_task(wo, 1, p);
Roland McGrathf4700212008-03-24 18:36:23 -07001651 if (ret)
Roland McGrath98abed02008-03-19 19:24:59 -07001652 return ret;
Roland McGrath98abed02008-03-19 19:24:59 -07001653 }
1654
1655 return 0;
1656}
1657
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001658static int child_wait_callback(wait_queue_t *wait, unsigned mode,
1659 int sync, void *key)
1660{
1661 struct wait_opts *wo = container_of(wait, struct wait_opts,
1662 child_wait);
1663 struct task_struct *p = key;
1664
Oleg Nesterov5c01ba42009-09-23 15:56:48 -07001665 if (!eligible_pid(wo, p))
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001666 return 0;
1667
Oleg Nesterovb4fe5182009-09-23 15:56:47 -07001668 if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
1669 return 0;
1670
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001671 return default_wake_function(wait, mode, sync, key);
1672}
1673
Oleg Nesterova7f07652009-09-23 15:56:44 -07001674void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
1675{
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001676 __wake_up_sync_key(&parent->signal->wait_chldexit,
1677 TASK_INTERRUPTIBLE, 1, p);
Oleg Nesterova7f07652009-09-23 15:56:44 -07001678}
1679
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001680static long do_wait(struct wait_opts *wo)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682 struct task_struct *tsk;
Roland McGrath98abed02008-03-19 19:24:59 -07001683 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001685 trace_sched_process_wait(wo->wo_pid);
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -04001686
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001687 init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
1688 wo->child_wait.private = current;
1689 add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690repeat:
Roland McGrath98abed02008-03-19 19:24:59 -07001691 /*
1692 * If there is nothing that can match our critiera just get out.
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001693 * We will clear ->notask_error to zero if we see any child that
1694 * might later match our criteria, even if we are not able to reap
1695 * it yet.
Roland McGrath98abed02008-03-19 19:24:59 -07001696 */
Oleg Nesterov64a16ca2009-06-17 16:27:40 -07001697 wo->notask_error = -ECHILD;
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001698 if ((wo->wo_type < PIDTYPE_MAX) &&
1699 (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
Oleg Nesterov64a16ca2009-06-17 16:27:40 -07001700 goto notask;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001701
Oleg Nesterovf95d39d2009-06-17 16:27:42 -07001702 set_current_state(TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 read_lock(&tasklist_lock);
1704 tsk = current;
1705 do {
Oleg Nesterov64a16ca2009-06-17 16:27:40 -07001706 retval = do_wait_thread(wo, tsk);
1707 if (retval)
Roland McGrath98abed02008-03-19 19:24:59 -07001708 goto end;
Oleg Nesterov64a16ca2009-06-17 16:27:40 -07001709
1710 retval = ptrace_do_wait(wo, tsk);
1711 if (retval)
1712 goto end;
Roland McGrath98abed02008-03-19 19:24:59 -07001713
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001714 if (wo->wo_flags & __WNOTHREAD)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 break;
Oleg Nesterova3f6dfb2009-06-17 16:27:41 -07001716 } while_each_thread(current, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717 read_unlock(&tasklist_lock);
Oleg Nesterovf2cc3eb2008-02-08 04:19:06 -08001718
Oleg Nesterov64a16ca2009-06-17 16:27:40 -07001719notask:
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001720 retval = wo->notask_error;
1721 if (!retval && !(wo->wo_flags & WNOHANG)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 retval = -ERESTARTSYS;
Roland McGrath98abed02008-03-19 19:24:59 -07001723 if (!signal_pending(current)) {
1724 schedule();
1725 goto repeat;
1726 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728end:
Oleg Nesterovf95d39d2009-06-17 16:27:42 -07001729 __set_current_state(TASK_RUNNING);
Oleg Nesterov0b7570e2009-09-23 15:56:46 -07001730 remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731 return retval;
1732}
1733
Heiko Carstens17da2bd2009-01-14 14:14:10 +01001734SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
1735 infop, int, options, struct rusage __user *, ru)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736{
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001737 struct wait_opts wo;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001738 struct pid *pid = NULL;
1739 enum pid_type type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 long ret;
1741
1742 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1743 return -EINVAL;
1744 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1745 return -EINVAL;
1746
1747 switch (which) {
1748 case P_ALL:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001749 type = PIDTYPE_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 break;
1751 case P_PID:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001752 type = PIDTYPE_PID;
1753 if (upid <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 return -EINVAL;
1755 break;
1756 case P_PGID:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001757 type = PIDTYPE_PGID;
1758 if (upid <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 break;
1761 default:
1762 return -EINVAL;
1763 }
1764
Eric W. Biederman161550d2008-02-08 04:19:14 -08001765 if (type < PIDTYPE_MAX)
1766 pid = find_get_pid(upid);
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001767
1768 wo.wo_type = type;
1769 wo.wo_pid = pid;
1770 wo.wo_flags = options;
1771 wo.wo_info = infop;
1772 wo.wo_stat = NULL;
1773 wo.wo_rusage = ru;
1774 ret = do_wait(&wo);
Vitaly Mayatskikhdfe16df2009-09-23 15:56:51 -07001775
1776 if (ret > 0) {
1777 ret = 0;
1778 } else if (infop) {
1779 /*
1780 * For a WNOHANG return, clear out all the fields
1781 * we would set so the user can easily tell the
1782 * difference.
1783 */
1784 if (!ret)
1785 ret = put_user(0, &infop->si_signo);
1786 if (!ret)
1787 ret = put_user(0, &infop->si_errno);
1788 if (!ret)
1789 ret = put_user(0, &infop->si_code);
1790 if (!ret)
1791 ret = put_user(0, &infop->si_pid);
1792 if (!ret)
1793 ret = put_user(0, &infop->si_uid);
1794 if (!ret)
1795 ret = put_user(0, &infop->si_status);
1796 }
1797
Eric W. Biederman161550d2008-02-08 04:19:14 -08001798 put_pid(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799
1800 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001801 asmlinkage_protect(5, ret, which, upid, infop, options, ru);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 return ret;
1803}
1804
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001805SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
1806 int, options, struct rusage __user *, ru)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807{
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001808 struct wait_opts wo;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001809 struct pid *pid = NULL;
1810 enum pid_type type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811 long ret;
1812
1813 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1814 __WNOTHREAD|__WCLONE|__WALL))
1815 return -EINVAL;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001816
1817 if (upid == -1)
1818 type = PIDTYPE_MAX;
1819 else if (upid < 0) {
1820 type = PIDTYPE_PGID;
1821 pid = find_get_pid(-upid);
1822 } else if (upid == 0) {
1823 type = PIDTYPE_PGID;
Oleg Nesterov2ae448e2009-04-02 16:58:36 -07001824 pid = get_task_pid(current, PIDTYPE_PGID);
Eric W. Biederman161550d2008-02-08 04:19:14 -08001825 } else /* upid > 0 */ {
1826 type = PIDTYPE_PID;
1827 pid = find_get_pid(upid);
1828 }
1829
Oleg Nesterov9e8ae012009-06-17 16:27:39 -07001830 wo.wo_type = type;
1831 wo.wo_pid = pid;
1832 wo.wo_flags = options | WEXITED;
1833 wo.wo_info = NULL;
1834 wo.wo_stat = stat_addr;
1835 wo.wo_rusage = ru;
1836 ret = do_wait(&wo);
Eric W. Biederman161550d2008-02-08 04:19:14 -08001837 put_pid(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838
1839 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001840 asmlinkage_protect(4, ret, upid, stat_addr, options, ru);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841 return ret;
1842}
1843
1844#ifdef __ARCH_WANT_SYS_WAITPID
1845
1846/*
1847 * sys_waitpid() remains for compatibility. waitpid() should be
1848 * implemented by calling sys_wait4() from libc.a.
1849 */
Heiko Carstens17da2bd2009-01-14 14:14:10 +01001850SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851{
1852 return sys_wait4(pid, stat_addr, options, NULL);
1853}
1854
1855#endif