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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/exit.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/mm.h> |
8 | #include <linux/slab.h> | |
9 | #include <linux/interrupt.h> | |
1da177e4 | 10 | #include <linux/module.h> |
c59ede7b | 11 | #include <linux/capability.h> |
1da177e4 LT |
12 | #include <linux/completion.h> |
13 | #include <linux/personality.h> | |
14 | #include <linux/tty.h> | |
da9cbc87 | 15 | #include <linux/iocontext.h> |
1da177e4 LT |
16 | #include <linux/key.h> |
17 | #include <linux/security.h> | |
18 | #include <linux/cpu.h> | |
19 | #include <linux/acct.h> | |
8f0ab514 | 20 | #include <linux/tsacct_kern.h> |
1da177e4 | 21 | #include <linux/file.h> |
9f3acc31 | 22 | #include <linux/fdtable.h> |
1da177e4 | 23 | #include <linux/binfmts.h> |
ab516013 | 24 | #include <linux/nsproxy.h> |
84d73786 | 25 | #include <linux/pid_namespace.h> |
1da177e4 LT |
26 | #include <linux/ptrace.h> |
27 | #include <linux/profile.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/proc_fs.h> | |
49d769d5 | 30 | #include <linux/kthread.h> |
1da177e4 | 31 | #include <linux/mempolicy.h> |
c757249a | 32 | #include <linux/taskstats_kern.h> |
ca74e92b | 33 | #include <linux/delayacct.h> |
83144186 | 34 | #include <linux/freezer.h> |
b4f48b63 | 35 | #include <linux/cgroup.h> |
1da177e4 | 36 | #include <linux/syscalls.h> |
7ed20e1a | 37 | #include <linux/signal.h> |
6a14c5c9 | 38 | #include <linux/posix-timers.h> |
9f46080c | 39 | #include <linux/cn_proc.h> |
de5097c2 | 40 | #include <linux/mutex.h> |
0771dfef | 41 | #include <linux/futex.h> |
b92ce558 | 42 | #include <linux/pipe_fs_i.h> |
fa84cb93 | 43 | #include <linux/audit.h> /* for audit_free() */ |
83cc5ed3 | 44 | #include <linux/resource.h> |
0d67a46d | 45 | #include <linux/blkdev.h> |
6eaeeaba | 46 | #include <linux/task_io_accounting_ops.h> |
30199f5a | 47 | #include <linux/tracehook.h> |
5ad4e53b | 48 | #include <linux/fs_struct.h> |
d84f4f99 | 49 | #include <linux/init_task.h> |
cdd6c482 | 50 | #include <linux/perf_event.h> |
ad8d75ff | 51 | #include <trace/events/sched.h> |
24f1e32c | 52 | #include <linux/hw_breakpoint.h> |
3d5992d2 | 53 | #include <linux/oom.h> |
54848d73 | 54 | #include <linux/writeback.h> |
40401530 | 55 | #include <linux/shm.h> |
1da177e4 LT |
56 | |
57 | #include <asm/uaccess.h> | |
58 | #include <asm/unistd.h> | |
59 | #include <asm/pgtable.h> | |
60 | #include <asm/mmu_context.h> | |
61 | ||
408b664a AB |
62 | static void exit_mm(struct task_struct * tsk); |
63 | ||
d40e48e0 | 64 | static void __unhash_process(struct task_struct *p, bool group_dead) |
1da177e4 LT |
65 | { |
66 | nr_threads--; | |
d40e48e0 | 67 | if (group_dead) { |
1da177e4 LT |
68 | detach_pid(p, PIDTYPE_PGID); |
69 | detach_pid(p, PIDTYPE_SID); | |
c97d9893 | 70 | |
5e85d4ab | 71 | list_del_rcu(&p->tasks); |
9cd80bbb | 72 | list_del_init(&p->sibling); |
909ea964 | 73 | __this_cpu_dec(process_counts); |
6347e900 EB |
74 | /* |
75 | * If we are the last child process in a pid namespace to be | |
76 | * reaped, notify the reaper sleeping zap_pid_ns_processes(). | |
77 | */ | |
78 | if (IS_ENABLED(CONFIG_PID_NS)) { | |
79 | struct task_struct *parent = p->real_parent; | |
80 | ||
81 | if ((task_active_pid_ns(p)->child_reaper == parent) && | |
82 | list_empty(&parent->children) && | |
83 | (parent->flags & PF_EXITING)) | |
84 | wake_up_process(parent); | |
85 | } | |
1da177e4 | 86 | } |
6347e900 | 87 | detach_pid(p, PIDTYPE_PID); |
47e65328 | 88 | list_del_rcu(&p->thread_group); |
1da177e4 LT |
89 | } |
90 | ||
6a14c5c9 ON |
91 | /* |
92 | * This function expects the tasklist_lock write-locked. | |
93 | */ | |
94 | static void __exit_signal(struct task_struct *tsk) | |
95 | { | |
96 | struct signal_struct *sig = tsk->signal; | |
d40e48e0 | 97 | bool group_dead = thread_group_leader(tsk); |
6a14c5c9 | 98 | struct sighand_struct *sighand; |
4ada856f | 99 | struct tty_struct *uninitialized_var(tty); |
6a14c5c9 | 100 | |
d11c563d | 101 | sighand = rcu_dereference_check(tsk->sighand, |
db1466b3 | 102 | lockdep_tasklist_lock_is_held()); |
6a14c5c9 ON |
103 | spin_lock(&sighand->siglock); |
104 | ||
105 | posix_cpu_timers_exit(tsk); | |
d40e48e0 | 106 | if (group_dead) { |
6a14c5c9 | 107 | posix_cpu_timers_exit_group(tsk); |
4ada856f ON |
108 | tty = sig->tty; |
109 | sig->tty = NULL; | |
4a599942 | 110 | } else { |
e0a70217 ON |
111 | /* |
112 | * This can only happen if the caller is de_thread(). | |
113 | * FIXME: this is the temporary hack, we should teach | |
114 | * posix-cpu-timers to handle this case correctly. | |
115 | */ | |
116 | if (unlikely(has_group_leader_pid(tsk))) | |
117 | posix_cpu_timers_exit_group(tsk); | |
118 | ||
6a14c5c9 ON |
119 | /* |
120 | * If there is any task waiting for the group exit | |
121 | * then notify it: | |
122 | */ | |
d344193a | 123 | if (sig->notify_count > 0 && !--sig->notify_count) |
6a14c5c9 | 124 | wake_up_process(sig->group_exit_task); |
6db840fa | 125 | |
6a14c5c9 ON |
126 | if (tsk == sig->curr_target) |
127 | sig->curr_target = next_thread(tsk); | |
128 | /* | |
129 | * Accumulate here the counters for all threads but the | |
130 | * group leader as they die, so they can be added into | |
131 | * the process-wide totals when those are taken. | |
132 | * The group leader stays around as a zombie as long | |
133 | * as there are other threads. When it gets reaped, | |
134 | * the exit.c code will add its counts into these totals. | |
135 | * We won't ever get here for the group leader, since it | |
136 | * will have been the last reference on the signal_struct. | |
137 | */ | |
64861634 MS |
138 | sig->utime += tsk->utime; |
139 | sig->stime += tsk->stime; | |
140 | sig->gtime += tsk->gtime; | |
6a14c5c9 ON |
141 | sig->min_flt += tsk->min_flt; |
142 | sig->maj_flt += tsk->maj_flt; | |
143 | sig->nvcsw += tsk->nvcsw; | |
144 | sig->nivcsw += tsk->nivcsw; | |
6eaeeaba ED |
145 | sig->inblock += task_io_get_inblock(tsk); |
146 | sig->oublock += task_io_get_oublock(tsk); | |
5995477a | 147 | task_io_accounting_add(&sig->ioac, &tsk->ioac); |
32bd671d | 148 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime; |
6a14c5c9 ON |
149 | } |
150 | ||
b3ac022c | 151 | sig->nr_threads--; |
d40e48e0 | 152 | __unhash_process(tsk, group_dead); |
5876700c | 153 | |
da7978b0 ON |
154 | /* |
155 | * Do this under ->siglock, we can race with another thread | |
156 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. | |
157 | */ | |
158 | flush_sigqueue(&tsk->pending); | |
a7e5328a | 159 | tsk->sighand = NULL; |
6a14c5c9 | 160 | spin_unlock(&sighand->siglock); |
6a14c5c9 | 161 | |
a7e5328a | 162 | __cleanup_sighand(sighand); |
6a14c5c9 | 163 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); |
d40e48e0 | 164 | if (group_dead) { |
6a14c5c9 | 165 | flush_sigqueue(&sig->shared_pending); |
4ada856f | 166 | tty_kref_put(tty); |
6a14c5c9 ON |
167 | } |
168 | } | |
169 | ||
8c7904a0 EB |
170 | static void delayed_put_task_struct(struct rcu_head *rhp) |
171 | { | |
0a16b607 MD |
172 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
173 | ||
4e231c79 | 174 | perf_event_delayed_put(tsk); |
0a16b607 MD |
175 | trace_sched_process_free(tsk); |
176 | put_task_struct(tsk); | |
8c7904a0 EB |
177 | } |
178 | ||
f470021a | 179 | |
1da177e4 LT |
180 | void release_task(struct task_struct * p) |
181 | { | |
36c8b586 | 182 | struct task_struct *leader; |
1da177e4 | 183 | int zap_leader; |
1f09f974 | 184 | repeat: |
c69e8d9c | 185 | /* don't need to get the RCU readlock here - the process is dead and |
d11c563d PM |
186 | * can't be modifying its own credentials. But shut RCU-lockdep up */ |
187 | rcu_read_lock(); | |
c69e8d9c | 188 | atomic_dec(&__task_cred(p)->user->processes); |
d11c563d | 189 | rcu_read_unlock(); |
c69e8d9c | 190 | |
60347f67 | 191 | proc_flush_task(p); |
0203026b | 192 | |
1da177e4 | 193 | write_lock_irq(&tasklist_lock); |
a288eecc | 194 | ptrace_release_task(p); |
1da177e4 | 195 | __exit_signal(p); |
35f5cad8 | 196 | |
1da177e4 LT |
197 | /* |
198 | * If we are the last non-leader member of the thread | |
199 | * group, and the leader is zombie, then notify the | |
200 | * group leader's parent process. (if it wants notification.) | |
201 | */ | |
202 | zap_leader = 0; | |
203 | leader = p->group_leader; | |
204 | if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { | |
1da177e4 LT |
205 | /* |
206 | * If we were the last child thread and the leader has | |
207 | * exited already, and the leader's parent ignores SIGCHLD, | |
208 | * then we are the one who should release the leader. | |
dae33574 | 209 | */ |
86773473 | 210 | zap_leader = do_notify_parent(leader, leader->exit_signal); |
dae33574 RM |
211 | if (zap_leader) |
212 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
213 | } |
214 | ||
1da177e4 | 215 | write_unlock_irq(&tasklist_lock); |
1da177e4 | 216 | release_thread(p); |
8c7904a0 | 217 | call_rcu(&p->rcu, delayed_put_task_struct); |
1da177e4 LT |
218 | |
219 | p = leader; | |
220 | if (unlikely(zap_leader)) | |
221 | goto repeat; | |
222 | } | |
223 | ||
1da177e4 LT |
224 | /* |
225 | * This checks not only the pgrp, but falls back on the pid if no | |
226 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly | |
227 | * without this... | |
04a2e6a5 EB |
228 | * |
229 | * The caller must hold rcu lock or the tasklist lock. | |
1da177e4 | 230 | */ |
04a2e6a5 | 231 | struct pid *session_of_pgrp(struct pid *pgrp) |
1da177e4 LT |
232 | { |
233 | struct task_struct *p; | |
04a2e6a5 | 234 | struct pid *sid = NULL; |
62dfb554 | 235 | |
04a2e6a5 | 236 | p = pid_task(pgrp, PIDTYPE_PGID); |
62dfb554 | 237 | if (p == NULL) |
04a2e6a5 | 238 | p = pid_task(pgrp, PIDTYPE_PID); |
62dfb554 | 239 | if (p != NULL) |
04a2e6a5 | 240 | sid = task_session(p); |
62dfb554 | 241 | |
1da177e4 LT |
242 | return sid; |
243 | } | |
244 | ||
245 | /* | |
246 | * Determine if a process group is "orphaned", according to the POSIX | |
247 | * definition in 2.2.2.52. Orphaned process groups are not to be affected | |
248 | * by terminal-generated stop signals. Newly orphaned process groups are | |
249 | * to receive a SIGHUP and a SIGCONT. | |
250 | * | |
251 | * "I ask you, have you ever known what it is to be an orphan?" | |
252 | */ | |
0475ac08 | 253 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) |
1da177e4 LT |
254 | { |
255 | struct task_struct *p; | |
1da177e4 | 256 | |
0475ac08 | 257 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
05e83df6 ON |
258 | if ((p == ignored_task) || |
259 | (p->exit_state && thread_group_empty(p)) || | |
260 | is_global_init(p->real_parent)) | |
1da177e4 | 261 | continue; |
05e83df6 | 262 | |
0475ac08 | 263 | if (task_pgrp(p->real_parent) != pgrp && |
05e83df6 ON |
264 | task_session(p->real_parent) == task_session(p)) |
265 | return 0; | |
0475ac08 | 266 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
05e83df6 ON |
267 | |
268 | return 1; | |
1da177e4 LT |
269 | } |
270 | ||
3e7cd6c4 | 271 | int is_current_pgrp_orphaned(void) |
1da177e4 LT |
272 | { |
273 | int retval; | |
274 | ||
275 | read_lock(&tasklist_lock); | |
3e7cd6c4 | 276 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); |
1da177e4 LT |
277 | read_unlock(&tasklist_lock); |
278 | ||
279 | return retval; | |
280 | } | |
281 | ||
961c4675 | 282 | static bool has_stopped_jobs(struct pid *pgrp) |
1da177e4 | 283 | { |
1da177e4 LT |
284 | struct task_struct *p; |
285 | ||
0475ac08 | 286 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
961c4675 ON |
287 | if (p->signal->flags & SIGNAL_STOP_STOPPED) |
288 | return true; | |
0475ac08 | 289 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
961c4675 ON |
290 | |
291 | return false; | |
1da177e4 LT |
292 | } |
293 | ||
f49ee505 ON |
294 | /* |
295 | * Check to see if any process groups have become orphaned as | |
296 | * a result of our exiting, and if they have any stopped jobs, | |
297 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
298 | */ | |
299 | static void | |
300 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) | |
301 | { | |
302 | struct pid *pgrp = task_pgrp(tsk); | |
303 | struct task_struct *ignored_task = tsk; | |
304 | ||
305 | if (!parent) | |
306 | /* exit: our father is in a different pgrp than | |
307 | * we are and we were the only connection outside. | |
308 | */ | |
309 | parent = tsk->real_parent; | |
310 | else | |
311 | /* reparent: our child is in a different pgrp than | |
312 | * we are, and it was the only connection outside. | |
313 | */ | |
314 | ignored_task = NULL; | |
315 | ||
316 | if (task_pgrp(parent) != pgrp && | |
317 | task_session(parent) == task_session(tsk) && | |
318 | will_become_orphaned_pgrp(pgrp, ignored_task) && | |
319 | has_stopped_jobs(pgrp)) { | |
320 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); | |
321 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); | |
322 | } | |
323 | } | |
324 | ||
1da177e4 | 325 | /** |
49d769d5 | 326 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd |
1da177e4 LT |
327 | * |
328 | * If a kernel thread is launched as a result of a system call, or if | |
49d769d5 EB |
329 | * it ever exits, it should generally reparent itself to kthreadd so it |
330 | * isn't in the way of other processes and is correctly cleaned up on exit. | |
1da177e4 LT |
331 | * |
332 | * The various task state such as scheduling policy and priority may have | |
333 | * been inherited from a user process, so we reset them to sane values here. | |
334 | * | |
49d769d5 | 335 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities. |
1da177e4 | 336 | */ |
49d769d5 | 337 | static void reparent_to_kthreadd(void) |
1da177e4 LT |
338 | { |
339 | write_lock_irq(&tasklist_lock); | |
340 | ||
341 | ptrace_unlink(current); | |
342 | /* Reparent to init */ | |
49d769d5 | 343 | current->real_parent = current->parent = kthreadd_task; |
f470021a | 344 | list_move_tail(¤t->sibling, ¤t->real_parent->children); |
1da177e4 LT |
345 | |
346 | /* Set the exit signal to SIGCHLD so we signal init on exit */ | |
347 | current->exit_signal = SIGCHLD; | |
348 | ||
e05606d3 | 349 | if (task_nice(current) < 0) |
1da177e4 LT |
350 | set_user_nice(current, 0); |
351 | /* cpus_allowed? */ | |
352 | /* rt_priority? */ | |
353 | /* signals? */ | |
1da177e4 LT |
354 | memcpy(current->signal->rlim, init_task.signal->rlim, |
355 | sizeof(current->signal->rlim)); | |
d84f4f99 DH |
356 | |
357 | atomic_inc(&init_cred.usage); | |
358 | commit_creds(&init_cred); | |
1da177e4 | 359 | write_unlock_irq(&tasklist_lock); |
1da177e4 LT |
360 | } |
361 | ||
8520d7c7 | 362 | void __set_special_pids(struct pid *pid) |
1da177e4 | 363 | { |
e19f247a | 364 | struct task_struct *curr = current->group_leader; |
1da177e4 | 365 | |
0d0df599 | 366 | if (task_session(curr) != pid) |
7d8da096 | 367 | change_pid(curr, PIDTYPE_SID, pid); |
1b0f7ffd ON |
368 | |
369 | if (task_pgrp(curr) != pid) | |
7d8da096 | 370 | change_pid(curr, PIDTYPE_PGID, pid); |
1da177e4 LT |
371 | } |
372 | ||
8520d7c7 | 373 | static void set_special_pids(struct pid *pid) |
1da177e4 LT |
374 | { |
375 | write_lock_irq(&tasklist_lock); | |
8520d7c7 | 376 | __set_special_pids(pid); |
1da177e4 LT |
377 | write_unlock_irq(&tasklist_lock); |
378 | } | |
379 | ||
380 | /* | |
87245135 ON |
381 | * Let kernel threads use this to say that they allow a certain signal. |
382 | * Must not be used if kthread was cloned with CLONE_SIGHAND. | |
1da177e4 LT |
383 | */ |
384 | int allow_signal(int sig) | |
385 | { | |
7ed20e1a | 386 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
387 | return -EINVAL; |
388 | ||
389 | spin_lock_irq(¤t->sighand->siglock); | |
87245135 | 390 | /* This is only needed for daemonize()'ed kthreads */ |
1da177e4 | 391 | sigdelset(¤t->blocked, sig); |
87245135 ON |
392 | /* |
393 | * Kernel threads handle their own signals. Let the signal code | |
394 | * know it'll be handled, so that they don't get converted to | |
395 | * SIGKILL or just silently dropped. | |
396 | */ | |
397 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; | |
1da177e4 LT |
398 | recalc_sigpending(); |
399 | spin_unlock_irq(¤t->sighand->siglock); | |
400 | return 0; | |
401 | } | |
402 | ||
403 | EXPORT_SYMBOL(allow_signal); | |
404 | ||
405 | int disallow_signal(int sig) | |
406 | { | |
7ed20e1a | 407 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
408 | return -EINVAL; |
409 | ||
410 | spin_lock_irq(¤t->sighand->siglock); | |
10ab825b | 411 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; |
1da177e4 LT |
412 | recalc_sigpending(); |
413 | spin_unlock_irq(¤t->sighand->siglock); | |
414 | return 0; | |
415 | } | |
416 | ||
417 | EXPORT_SYMBOL(disallow_signal); | |
418 | ||
419 | /* | |
420 | * Put all the gunge required to become a kernel thread without | |
421 | * attached user resources in one place where it belongs. | |
422 | */ | |
423 | ||
424 | void daemonize(const char *name, ...) | |
425 | { | |
426 | va_list args; | |
1da177e4 LT |
427 | sigset_t blocked; |
428 | ||
429 | va_start(args, name); | |
430 | vsnprintf(current->comm, sizeof(current->comm), name, args); | |
431 | va_end(args); | |
432 | ||
433 | /* | |
434 | * If we were started as result of loading a module, close all of the | |
435 | * user space pages. We don't need them, and if we didn't close them | |
436 | * they would be locked into memory. | |
437 | */ | |
438 | exit_mm(current); | |
83144186 | 439 | /* |
37f08be1 | 440 | * We don't want to get frozen, in case system-wide hibernation |
83144186 RW |
441 | * or suspend transition begins right now. |
442 | */ | |
7b34e428 | 443 | current->flags |= (PF_NOFREEZE | PF_KTHREAD); |
1da177e4 | 444 | |
8520d7c7 ON |
445 | if (current->nsproxy != &init_nsproxy) { |
446 | get_nsproxy(&init_nsproxy); | |
447 | switch_task_namespaces(current, &init_nsproxy); | |
448 | } | |
297bd42b | 449 | set_special_pids(&init_struct_pid); |
24ec839c | 450 | proc_clear_tty(current); |
1da177e4 LT |
451 | |
452 | /* Block and flush all signals */ | |
453 | sigfillset(&blocked); | |
454 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
455 | flush_signals(current); | |
456 | ||
457 | /* Become as one with the init task */ | |
458 | ||
3e93cd67 | 459 | daemonize_fs_struct(); |
d4c5e41f | 460 | exit_files(current); |
1da177e4 LT |
461 | current->files = init_task.files; |
462 | atomic_inc(¤t->files->count); | |
463 | ||
49d769d5 | 464 | reparent_to_kthreadd(); |
1da177e4 LT |
465 | } |
466 | ||
467 | EXPORT_SYMBOL(daemonize); | |
468 | ||
858119e1 | 469 | static void close_files(struct files_struct * files) |
1da177e4 LT |
470 | { |
471 | int i, j; | |
badf1662 | 472 | struct fdtable *fdt; |
1da177e4 LT |
473 | |
474 | j = 0; | |
4fb3a538 DS |
475 | |
476 | /* | |
477 | * It is safe to dereference the fd table without RCU or | |
478 | * ->file_lock because this is the last reference to the | |
d11c563d | 479 | * files structure. But use RCU to shut RCU-lockdep up. |
4fb3a538 | 480 | */ |
d11c563d | 481 | rcu_read_lock(); |
badf1662 | 482 | fdt = files_fdtable(files); |
d11c563d | 483 | rcu_read_unlock(); |
1da177e4 LT |
484 | for (;;) { |
485 | unsigned long set; | |
486 | i = j * __NFDBITS; | |
bbea9f69 | 487 | if (i >= fdt->max_fds) |
1da177e4 | 488 | break; |
1fd36adc | 489 | set = fdt->open_fds[j++]; |
1da177e4 LT |
490 | while (set) { |
491 | if (set & 1) { | |
badf1662 | 492 | struct file * file = xchg(&fdt->fd[i], NULL); |
944be0b2 | 493 | if (file) { |
1da177e4 | 494 | filp_close(file, files); |
944be0b2 IM |
495 | cond_resched(); |
496 | } | |
1da177e4 LT |
497 | } |
498 | i++; | |
499 | set >>= 1; | |
500 | } | |
501 | } | |
502 | } | |
503 | ||
504 | struct files_struct *get_files_struct(struct task_struct *task) | |
505 | { | |
506 | struct files_struct *files; | |
507 | ||
508 | task_lock(task); | |
509 | files = task->files; | |
510 | if (files) | |
511 | atomic_inc(&files->count); | |
512 | task_unlock(task); | |
513 | ||
514 | return files; | |
515 | } | |
516 | ||
7ad5b3a5 | 517 | void put_files_struct(struct files_struct *files) |
1da177e4 | 518 | { |
badf1662 DS |
519 | struct fdtable *fdt; |
520 | ||
1da177e4 LT |
521 | if (atomic_dec_and_test(&files->count)) { |
522 | close_files(files); | |
523 | /* | |
524 | * Free the fd and fdset arrays if we expanded them. | |
ab2af1f5 DS |
525 | * If the fdtable was embedded, pass files for freeing |
526 | * at the end of the RCU grace period. Otherwise, | |
527 | * you can free files immediately. | |
1da177e4 | 528 | */ |
d11c563d | 529 | rcu_read_lock(); |
badf1662 | 530 | fdt = files_fdtable(files); |
4fd45812 | 531 | if (fdt != &files->fdtab) |
ab2af1f5 | 532 | kmem_cache_free(files_cachep, files); |
01b2d93c | 533 | free_fdtable(fdt); |
d11c563d | 534 | rcu_read_unlock(); |
1da177e4 LT |
535 | } |
536 | } | |
537 | ||
3b125388 | 538 | void reset_files_struct(struct files_struct *files) |
3b9b8ab6 | 539 | { |
3b125388 | 540 | struct task_struct *tsk = current; |
3b9b8ab6 KK |
541 | struct files_struct *old; |
542 | ||
543 | old = tsk->files; | |
544 | task_lock(tsk); | |
545 | tsk->files = files; | |
546 | task_unlock(tsk); | |
547 | put_files_struct(old); | |
548 | } | |
3b9b8ab6 | 549 | |
1ec7f1dd | 550 | void exit_files(struct task_struct *tsk) |
1da177e4 LT |
551 | { |
552 | struct files_struct * files = tsk->files; | |
553 | ||
554 | if (files) { | |
555 | task_lock(tsk); | |
556 | tsk->files = NULL; | |
557 | task_unlock(tsk); | |
558 | put_files_struct(files); | |
559 | } | |
560 | } | |
561 | ||
cf475ad2 BS |
562 | #ifdef CONFIG_MM_OWNER |
563 | /* | |
733eda7a | 564 | * A task is exiting. If it owned this mm, find a new owner for the mm. |
cf475ad2 | 565 | */ |
cf475ad2 BS |
566 | void mm_update_next_owner(struct mm_struct *mm) |
567 | { | |
568 | struct task_struct *c, *g, *p = current; | |
569 | ||
570 | retry: | |
733eda7a KH |
571 | /* |
572 | * If the exiting or execing task is not the owner, it's | |
573 | * someone else's problem. | |
574 | */ | |
575 | if (mm->owner != p) | |
cf475ad2 | 576 | return; |
733eda7a KH |
577 | /* |
578 | * The current owner is exiting/execing and there are no other | |
579 | * candidates. Do not leave the mm pointing to a possibly | |
580 | * freed task structure. | |
581 | */ | |
582 | if (atomic_read(&mm->mm_users) <= 1) { | |
583 | mm->owner = NULL; | |
584 | return; | |
585 | } | |
cf475ad2 BS |
586 | |
587 | read_lock(&tasklist_lock); | |
588 | /* | |
589 | * Search in the children | |
590 | */ | |
591 | list_for_each_entry(c, &p->children, sibling) { | |
592 | if (c->mm == mm) | |
593 | goto assign_new_owner; | |
594 | } | |
595 | ||
596 | /* | |
597 | * Search in the siblings | |
598 | */ | |
dea33cfd | 599 | list_for_each_entry(c, &p->real_parent->children, sibling) { |
cf475ad2 BS |
600 | if (c->mm == mm) |
601 | goto assign_new_owner; | |
602 | } | |
603 | ||
604 | /* | |
605 | * Search through everything else. We should not get | |
606 | * here often | |
607 | */ | |
608 | do_each_thread(g, c) { | |
609 | if (c->mm == mm) | |
610 | goto assign_new_owner; | |
611 | } while_each_thread(g, c); | |
612 | ||
613 | read_unlock(&tasklist_lock); | |
31a78f23 BS |
614 | /* |
615 | * We found no owner yet mm_users > 1: this implies that we are | |
616 | * most likely racing with swapoff (try_to_unuse()) or /proc or | |
e5991371 | 617 | * ptrace or page migration (get_task_mm()). Mark owner as NULL. |
31a78f23 | 618 | */ |
31a78f23 | 619 | mm->owner = NULL; |
cf475ad2 BS |
620 | return; |
621 | ||
622 | assign_new_owner: | |
623 | BUG_ON(c == p); | |
624 | get_task_struct(c); | |
625 | /* | |
626 | * The task_lock protects c->mm from changing. | |
627 | * We always want mm->owner->mm == mm | |
628 | */ | |
629 | task_lock(c); | |
e5991371 HD |
630 | /* |
631 | * Delay read_unlock() till we have the task_lock() | |
632 | * to ensure that c does not slip away underneath us | |
633 | */ | |
634 | read_unlock(&tasklist_lock); | |
cf475ad2 BS |
635 | if (c->mm != mm) { |
636 | task_unlock(c); | |
637 | put_task_struct(c); | |
638 | goto retry; | |
639 | } | |
cf475ad2 BS |
640 | mm->owner = c; |
641 | task_unlock(c); | |
642 | put_task_struct(c); | |
643 | } | |
644 | #endif /* CONFIG_MM_OWNER */ | |
645 | ||
1da177e4 LT |
646 | /* |
647 | * Turn us into a lazy TLB process if we | |
648 | * aren't already.. | |
649 | */ | |
408b664a | 650 | static void exit_mm(struct task_struct * tsk) |
1da177e4 LT |
651 | { |
652 | struct mm_struct *mm = tsk->mm; | |
b564daf8 | 653 | struct core_state *core_state; |
1da177e4 | 654 | |
48d212a2 | 655 | mm_release(tsk, mm); |
1da177e4 LT |
656 | if (!mm) |
657 | return; | |
4fe7efdb | 658 | sync_mm_rss(mm); |
1da177e4 LT |
659 | /* |
660 | * Serialize with any possible pending coredump. | |
999d9fc1 | 661 | * We must hold mmap_sem around checking core_state |
1da177e4 | 662 | * and clearing tsk->mm. The core-inducing thread |
999d9fc1 | 663 | * will increment ->nr_threads for each thread in the |
1da177e4 LT |
664 | * group with ->mm != NULL. |
665 | */ | |
666 | down_read(&mm->mmap_sem); | |
b564daf8 ON |
667 | core_state = mm->core_state; |
668 | if (core_state) { | |
669 | struct core_thread self; | |
1da177e4 | 670 | up_read(&mm->mmap_sem); |
1da177e4 | 671 | |
b564daf8 ON |
672 | self.task = tsk; |
673 | self.next = xchg(&core_state->dumper.next, &self); | |
674 | /* | |
675 | * Implies mb(), the result of xchg() must be visible | |
676 | * to core_state->dumper. | |
677 | */ | |
678 | if (atomic_dec_and_test(&core_state->nr_threads)) | |
679 | complete(&core_state->startup); | |
1da177e4 | 680 | |
a94e2d40 ON |
681 | for (;;) { |
682 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
683 | if (!self.task) /* see coredump_finish() */ | |
684 | break; | |
685 | schedule(); | |
686 | } | |
687 | __set_task_state(tsk, TASK_RUNNING); | |
1da177e4 LT |
688 | down_read(&mm->mmap_sem); |
689 | } | |
690 | atomic_inc(&mm->mm_count); | |
125e1874 | 691 | BUG_ON(mm != tsk->active_mm); |
1da177e4 LT |
692 | /* more a memory barrier than a real lock */ |
693 | task_lock(tsk); | |
694 | tsk->mm = NULL; | |
695 | up_read(&mm->mmap_sem); | |
696 | enter_lazy_tlb(mm, current); | |
697 | task_unlock(tsk); | |
cf475ad2 | 698 | mm_update_next_owner(mm); |
1da177e4 LT |
699 | mmput(mm); |
700 | } | |
701 | ||
1da177e4 | 702 | /* |
ebec18a6 LP |
703 | * When we die, we re-parent all our children, and try to: |
704 | * 1. give them to another thread in our thread group, if such a member exists | |
705 | * 2. give it to the first ancestor process which prctl'd itself as a | |
706 | * child_subreaper for its children (like a service manager) | |
707 | * 3. give it to the init process (PID 1) in our pid namespace | |
1da177e4 | 708 | */ |
950bbabb | 709 | static struct task_struct *find_new_reaper(struct task_struct *father) |
d16e15f5 NK |
710 | __releases(&tasklist_lock) |
711 | __acquires(&tasklist_lock) | |
1da177e4 | 712 | { |
950bbabb ON |
713 | struct pid_namespace *pid_ns = task_active_pid_ns(father); |
714 | struct task_struct *thread; | |
1da177e4 | 715 | |
950bbabb ON |
716 | thread = father; |
717 | while_each_thread(father, thread) { | |
718 | if (thread->flags & PF_EXITING) | |
719 | continue; | |
720 | if (unlikely(pid_ns->child_reaper == father)) | |
721 | pid_ns->child_reaper = thread; | |
722 | return thread; | |
723 | } | |
1da177e4 | 724 | |
950bbabb ON |
725 | if (unlikely(pid_ns->child_reaper == father)) { |
726 | write_unlock_irq(&tasklist_lock); | |
397a21f2 DV |
727 | if (unlikely(pid_ns == &init_pid_ns)) { |
728 | panic("Attempted to kill init! exitcode=0x%08x\n", | |
729 | father->signal->group_exit_code ?: | |
730 | father->exit_code); | |
731 | } | |
1da177e4 | 732 | |
950bbabb ON |
733 | zap_pid_ns_processes(pid_ns); |
734 | write_lock_irq(&tasklist_lock); | |
1da177e4 | 735 | /* |
950bbabb ON |
736 | * We can not clear ->child_reaper or leave it alone. |
737 | * There may by stealth EXIT_DEAD tasks on ->children, | |
738 | * forget_original_parent() must move them somewhere. | |
1da177e4 | 739 | */ |
950bbabb | 740 | pid_ns->child_reaper = init_pid_ns.child_reaper; |
ebec18a6 LP |
741 | } else if (father->signal->has_child_subreaper) { |
742 | struct task_struct *reaper; | |
743 | ||
744 | /* | |
745 | * Find the first ancestor marked as child_subreaper. | |
746 | * Note that the code below checks same_thread_group(reaper, | |
747 | * pid_ns->child_reaper). This is what we need to DTRT in a | |
748 | * PID namespace. However we still need the check above, see | |
749 | * http://marc.info/?l=linux-kernel&m=131385460420380 | |
750 | */ | |
751 | for (reaper = father->real_parent; | |
752 | reaper != &init_task; | |
753 | reaper = reaper->real_parent) { | |
754 | if (same_thread_group(reaper, pid_ns->child_reaper)) | |
755 | break; | |
756 | if (!reaper->signal->is_child_subreaper) | |
757 | continue; | |
758 | thread = reaper; | |
759 | do { | |
760 | if (!(thread->flags & PF_EXITING)) | |
761 | return reaper; | |
762 | } while_each_thread(reaper, thread); | |
763 | } | |
1da177e4 | 764 | } |
762a24be | 765 | |
950bbabb ON |
766 | return pid_ns->child_reaper; |
767 | } | |
768 | ||
5dfc80be ON |
769 | /* |
770 | * Any that need to be release_task'd are put on the @dead list. | |
771 | */ | |
9cd80bbb | 772 | static void reparent_leader(struct task_struct *father, struct task_struct *p, |
5dfc80be ON |
773 | struct list_head *dead) |
774 | { | |
5dfc80be ON |
775 | list_move_tail(&p->sibling, &p->real_parent->children); |
776 | ||
0976a03e | 777 | if (p->exit_state == EXIT_DEAD) |
5dfc80be ON |
778 | return; |
779 | /* | |
780 | * If this is a threaded reparent there is no need to | |
781 | * notify anyone anything has happened. | |
782 | */ | |
783 | if (same_thread_group(p->real_parent, father)) | |
784 | return; | |
785 | ||
786 | /* We don't want people slaying init. */ | |
787 | p->exit_signal = SIGCHLD; | |
788 | ||
789 | /* If it has exited notify the new parent about this child's death. */ | |
d21142ec | 790 | if (!p->ptrace && |
5dfc80be | 791 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { |
86773473 | 792 | if (do_notify_parent(p, p->exit_signal)) { |
5dfc80be ON |
793 | p->exit_state = EXIT_DEAD; |
794 | list_move_tail(&p->sibling, dead); | |
795 | } | |
796 | } | |
797 | ||
798 | kill_orphaned_pgrp(p, father); | |
799 | } | |
800 | ||
762a24be | 801 | static void forget_original_parent(struct task_struct *father) |
1da177e4 | 802 | { |
950bbabb | 803 | struct task_struct *p, *n, *reaper; |
5dfc80be | 804 | LIST_HEAD(dead_children); |
762a24be ON |
805 | |
806 | write_lock_irq(&tasklist_lock); | |
c7e49c14 ON |
807 | /* |
808 | * Note that exit_ptrace() and find_new_reaper() might | |
809 | * drop tasklist_lock and reacquire it. | |
810 | */ | |
811 | exit_ptrace(father); | |
950bbabb | 812 | reaper = find_new_reaper(father); |
f470021a | 813 | |
03ff1797 | 814 | list_for_each_entry_safe(p, n, &father->children, sibling) { |
9cd80bbb ON |
815 | struct task_struct *t = p; |
816 | do { | |
817 | t->real_parent = reaper; | |
818 | if (t->parent == father) { | |
d21142ec | 819 | BUG_ON(t->ptrace); |
9cd80bbb ON |
820 | t->parent = t->real_parent; |
821 | } | |
822 | if (t->pdeath_signal) | |
823 | group_send_sig_info(t->pdeath_signal, | |
824 | SEND_SIG_NOINFO, t); | |
825 | } while_each_thread(p, t); | |
826 | reparent_leader(father, p, &dead_children); | |
1da177e4 | 827 | } |
762a24be | 828 | write_unlock_irq(&tasklist_lock); |
5dfc80be | 829 | |
762a24be | 830 | BUG_ON(!list_empty(&father->children)); |
762a24be | 831 | |
5dfc80be ON |
832 | list_for_each_entry_safe(p, n, &dead_children, sibling) { |
833 | list_del_init(&p->sibling); | |
39c626ae ON |
834 | release_task(p); |
835 | } | |
1da177e4 LT |
836 | } |
837 | ||
838 | /* | |
839 | * Send signals to all our closest relatives so that they know | |
840 | * to properly mourn us.. | |
841 | */ | |
821c7de7 | 842 | static void exit_notify(struct task_struct *tsk, int group_dead) |
1da177e4 | 843 | { |
53c8f9f1 | 844 | bool autoreap; |
1da177e4 | 845 | |
1da177e4 LT |
846 | /* |
847 | * This does two things: | |
848 | * | |
849 | * A. Make init inherit all the child processes | |
850 | * B. Check to see if any process groups have become orphaned | |
851 | * as a result of our exiting, and if they have any stopped | |
852 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
853 | */ | |
762a24be | 854 | forget_original_parent(tsk); |
2e4a7072 | 855 | exit_task_namespaces(tsk); |
1da177e4 | 856 | |
762a24be | 857 | write_lock_irq(&tasklist_lock); |
821c7de7 ON |
858 | if (group_dead) |
859 | kill_orphaned_pgrp(tsk->group_leader, NULL); | |
1da177e4 | 860 | |
45cdf5cc ON |
861 | if (unlikely(tsk->ptrace)) { |
862 | int sig = thread_group_leader(tsk) && | |
863 | thread_group_empty(tsk) && | |
864 | !ptrace_reparented(tsk) ? | |
865 | tsk->exit_signal : SIGCHLD; | |
866 | autoreap = do_notify_parent(tsk, sig); | |
867 | } else if (thread_group_leader(tsk)) { | |
868 | autoreap = thread_group_empty(tsk) && | |
869 | do_notify_parent(tsk, tsk->exit_signal); | |
870 | } else { | |
871 | autoreap = true; | |
872 | } | |
1da177e4 | 873 | |
53c8f9f1 | 874 | tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE; |
1da177e4 | 875 | |
9c339168 ON |
876 | /* mt-exec, de_thread() is waiting for group leader */ |
877 | if (unlikely(tsk->signal->notify_count < 0)) | |
6db840fa | 878 | wake_up_process(tsk->signal->group_exit_task); |
1da177e4 LT |
879 | write_unlock_irq(&tasklist_lock); |
880 | ||
1da177e4 | 881 | /* If the process is dead, release it - nobody will wait for it */ |
53c8f9f1 | 882 | if (autoreap) |
1da177e4 | 883 | release_task(tsk); |
1da177e4 LT |
884 | } |
885 | ||
e18eecb8 JD |
886 | #ifdef CONFIG_DEBUG_STACK_USAGE |
887 | static void check_stack_usage(void) | |
888 | { | |
889 | static DEFINE_SPINLOCK(low_water_lock); | |
890 | static int lowest_to_date = THREAD_SIZE; | |
e18eecb8 JD |
891 | unsigned long free; |
892 | ||
7c9f8861 | 893 | free = stack_not_used(current); |
e18eecb8 JD |
894 | |
895 | if (free >= lowest_to_date) | |
896 | return; | |
897 | ||
898 | spin_lock(&low_water_lock); | |
899 | if (free < lowest_to_date) { | |
168eeccb TB |
900 | printk(KERN_WARNING "%s (%d) used greatest stack depth: " |
901 | "%lu bytes left\n", | |
902 | current->comm, task_pid_nr(current), free); | |
e18eecb8 JD |
903 | lowest_to_date = free; |
904 | } | |
905 | spin_unlock(&low_water_lock); | |
906 | } | |
907 | #else | |
908 | static inline void check_stack_usage(void) {} | |
909 | #endif | |
910 | ||
9402c95f | 911 | void do_exit(long code) |
1da177e4 LT |
912 | { |
913 | struct task_struct *tsk = current; | |
914 | int group_dead; | |
915 | ||
916 | profile_task_exit(tsk); | |
917 | ||
73c10101 | 918 | WARN_ON(blk_needs_flush_plug(tsk)); |
22e2c507 | 919 | |
1da177e4 LT |
920 | if (unlikely(in_interrupt())) |
921 | panic("Aiee, killing interrupt handler!"); | |
922 | if (unlikely(!tsk->pid)) | |
923 | panic("Attempted to kill the idle task!"); | |
1da177e4 | 924 | |
33dd94ae NE |
925 | /* |
926 | * If do_exit is called because this processes oopsed, it's possible | |
927 | * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before | |
928 | * continuing. Amongst other possible reasons, this is to prevent | |
929 | * mm_release()->clear_child_tid() from writing to a user-controlled | |
930 | * kernel address. | |
931 | */ | |
932 | set_fs(USER_DS); | |
933 | ||
a288eecc | 934 | ptrace_event(PTRACE_EVENT_EXIT, code); |
1da177e4 | 935 | |
e0e81739 DH |
936 | validate_creds_for_do_exit(tsk); |
937 | ||
df164db5 AN |
938 | /* |
939 | * We're taking recursive faults here in do_exit. Safest is to just | |
940 | * leave this task alone and wait for reboot. | |
941 | */ | |
942 | if (unlikely(tsk->flags & PF_EXITING)) { | |
943 | printk(KERN_ALERT | |
944 | "Fixing recursive fault but reboot is needed!\n"); | |
778e9a9c AK |
945 | /* |
946 | * We can do this unlocked here. The futex code uses | |
947 | * this flag just to verify whether the pi state | |
948 | * cleanup has been done or not. In the worst case it | |
949 | * loops once more. We pretend that the cleanup was | |
950 | * done as there is no way to return. Either the | |
951 | * OWNER_DIED bit is set by now or we push the blocked | |
952 | * task into the wait for ever nirwana as well. | |
953 | */ | |
954 | tsk->flags |= PF_EXITPIDONE; | |
df164db5 AN |
955 | set_current_state(TASK_UNINTERRUPTIBLE); |
956 | schedule(); | |
957 | } | |
958 | ||
d12619b5 | 959 | exit_signals(tsk); /* sets PF_EXITING */ |
778e9a9c AK |
960 | /* |
961 | * tsk->flags are checked in the futex code to protect against | |
e73f8959 ON |
962 | * an exiting task cleaning up the robust pi futexes, and in |
963 | * task_work_add() to avoid the race with exit_task_work(). | |
778e9a9c | 964 | */ |
d2ee7198 | 965 | smp_mb(); |
1d615482 | 966 | raw_spin_unlock_wait(&tsk->pi_lock); |
1da177e4 | 967 | |
e73f8959 | 968 | exit_task_work(tsk); |
5234ffb9 | 969 | |
1da177e4 LT |
970 | if (unlikely(in_atomic())) |
971 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", | |
ba25f9dc | 972 | current->comm, task_pid_nr(current), |
1da177e4 LT |
973 | preempt_count()); |
974 | ||
975 | acct_update_integrals(tsk); | |
48d212a2 LT |
976 | /* sync mm's RSS info before statistics gathering */ |
977 | if (tsk->mm) | |
978 | sync_mm_rss(tsk->mm); | |
1da177e4 | 979 | group_dead = atomic_dec_and_test(&tsk->signal->live); |
c3068951 | 980 | if (group_dead) { |
778e9a9c | 981 | hrtimer_cancel(&tsk->signal->real_timer); |
25f407f0 | 982 | exit_itimers(tsk->signal); |
1f10206c JP |
983 | if (tsk->mm) |
984 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); | |
c3068951 | 985 | } |
f6ec29a4 | 986 | acct_collect(code, group_dead); |
522ed776 MT |
987 | if (group_dead) |
988 | tty_audit_exit(); | |
a4ff8dba | 989 | audit_free(tsk); |
115085ea | 990 | |
48d212a2 | 991 | tsk->exit_code = code; |
115085ea | 992 | taskstats_exit(tsk, group_dead); |
c757249a | 993 | |
1da177e4 LT |
994 | exit_mm(tsk); |
995 | ||
0e464814 | 996 | if (group_dead) |
f6ec29a4 | 997 | acct_process(); |
0a16b607 MD |
998 | trace_sched_process_exit(tsk); |
999 | ||
1da177e4 | 1000 | exit_sem(tsk); |
b34a6b1d | 1001 | exit_shm(tsk); |
1ec7f1dd AV |
1002 | exit_files(tsk); |
1003 | exit_fs(tsk); | |
e18eecb8 | 1004 | check_stack_usage(); |
1da177e4 | 1005 | exit_thread(); |
0b3fcf17 SE |
1006 | |
1007 | /* | |
1008 | * Flush inherited counters to the parent - before the parent | |
1009 | * gets woken up by child-exit notifications. | |
1010 | * | |
1011 | * because of cgroup mode, must be called before cgroup_exit() | |
1012 | */ | |
1013 | perf_event_exit_task(tsk); | |
1014 | ||
b4f48b63 | 1015 | cgroup_exit(tsk, 1); |
1da177e4 | 1016 | |
5ec93d11 | 1017 | if (group_dead) |
1da177e4 LT |
1018 | disassociate_ctty(1); |
1019 | ||
a1261f54 | 1020 | module_put(task_thread_info(tsk)->exec_domain->module); |
1da177e4 | 1021 | |
9f46080c | 1022 | proc_exit_connector(tsk); |
33b2fb30 | 1023 | |
24f1e32c FW |
1024 | /* |
1025 | * FIXME: do that only when needed, using sched_exit tracepoint | |
1026 | */ | |
bf26c018 | 1027 | ptrace_put_breakpoints(tsk); |
33b2fb30 | 1028 | |
821c7de7 | 1029 | exit_notify(tsk, group_dead); |
1da177e4 | 1030 | #ifdef CONFIG_NUMA |
c0ff7453 | 1031 | task_lock(tsk); |
f0be3d32 | 1032 | mpol_put(tsk->mempolicy); |
1da177e4 | 1033 | tsk->mempolicy = NULL; |
c0ff7453 | 1034 | task_unlock(tsk); |
1da177e4 | 1035 | #endif |
42b2dd0a | 1036 | #ifdef CONFIG_FUTEX |
c87e2837 IM |
1037 | if (unlikely(current->pi_state_cache)) |
1038 | kfree(current->pi_state_cache); | |
42b2dd0a | 1039 | #endif |
de5097c2 | 1040 | /* |
9a11b49a | 1041 | * Make sure we are holding no locks: |
de5097c2 | 1042 | */ |
9a11b49a | 1043 | debug_check_no_locks_held(tsk); |
778e9a9c AK |
1044 | /* |
1045 | * We can do this unlocked here. The futex code uses this flag | |
1046 | * just to verify whether the pi state cleanup has been done | |
1047 | * or not. In the worst case it loops once more. | |
1048 | */ | |
1049 | tsk->flags |= PF_EXITPIDONE; | |
1da177e4 | 1050 | |
afc847b7 | 1051 | if (tsk->io_context) |
b69f2292 | 1052 | exit_io_context(tsk); |
afc847b7 | 1053 | |
b92ce558 JA |
1054 | if (tsk->splice_pipe) |
1055 | __free_pipe_info(tsk->splice_pipe); | |
1056 | ||
e0e81739 DH |
1057 | validate_creds_for_do_exit(tsk); |
1058 | ||
7407251a | 1059 | preempt_disable(); |
54848d73 WF |
1060 | if (tsk->nr_dirtied) |
1061 | __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied); | |
f41d911f | 1062 | exit_rcu(); |
b5740f4b YG |
1063 | |
1064 | /* | |
1065 | * The setting of TASK_RUNNING by try_to_wake_up() may be delayed | |
1066 | * when the following two conditions become true. | |
1067 | * - There is race condition of mmap_sem (It is acquired by | |
1068 | * exit_mm()), and | |
1069 | * - SMI occurs before setting TASK_RUNINNG. | |
1070 | * (or hypervisor of virtual machine switches to other guest) | |
1071 | * As a result, we may become TASK_RUNNING after becoming TASK_DEAD | |
1072 | * | |
1073 | * To avoid it, we have to wait for releasing tsk->pi_lock which | |
1074 | * is held by try_to_wake_up() | |
1075 | */ | |
1076 | smp_mb(); | |
1077 | raw_spin_unlock_wait(&tsk->pi_lock); | |
1078 | ||
55a101f8 | 1079 | /* causes final put_task_struct in finish_task_switch(). */ |
c394cc9f | 1080 | tsk->state = TASK_DEAD; |
a585042f | 1081 | tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */ |
1da177e4 LT |
1082 | schedule(); |
1083 | BUG(); | |
1084 | /* Avoid "noreturn function does return". */ | |
54306cf0 AC |
1085 | for (;;) |
1086 | cpu_relax(); /* For when BUG is null */ | |
1da177e4 LT |
1087 | } |
1088 | ||
012914da RA |
1089 | EXPORT_SYMBOL_GPL(do_exit); |
1090 | ||
9402c95f | 1091 | void complete_and_exit(struct completion *comp, long code) |
1da177e4 LT |
1092 | { |
1093 | if (comp) | |
1094 | complete(comp); | |
55a101f8 | 1095 | |
1da177e4 LT |
1096 | do_exit(code); |
1097 | } | |
1098 | ||
1099 | EXPORT_SYMBOL(complete_and_exit); | |
1100 | ||
754fe8d2 | 1101 | SYSCALL_DEFINE1(exit, int, error_code) |
1da177e4 LT |
1102 | { |
1103 | do_exit((error_code&0xff)<<8); | |
1104 | } | |
1105 | ||
1da177e4 LT |
1106 | /* |
1107 | * Take down every thread in the group. This is called by fatal signals | |
1108 | * as well as by sys_exit_group (below). | |
1109 | */ | |
9402c95f | 1110 | void |
1da177e4 LT |
1111 | do_group_exit(int exit_code) |
1112 | { | |
bfc4b089 ON |
1113 | struct signal_struct *sig = current->signal; |
1114 | ||
1da177e4 LT |
1115 | BUG_ON(exit_code & 0x80); /* core dumps don't get here */ |
1116 | ||
bfc4b089 ON |
1117 | if (signal_group_exit(sig)) |
1118 | exit_code = sig->group_exit_code; | |
1da177e4 | 1119 | else if (!thread_group_empty(current)) { |
1da177e4 | 1120 | struct sighand_struct *const sighand = current->sighand; |
1da177e4 | 1121 | spin_lock_irq(&sighand->siglock); |
ed5d2cac | 1122 | if (signal_group_exit(sig)) |
1da177e4 LT |
1123 | /* Another thread got here before we took the lock. */ |
1124 | exit_code = sig->group_exit_code; | |
1125 | else { | |
1da177e4 | 1126 | sig->group_exit_code = exit_code; |
ed5d2cac | 1127 | sig->flags = SIGNAL_GROUP_EXIT; |
1da177e4 LT |
1128 | zap_other_threads(current); |
1129 | } | |
1130 | spin_unlock_irq(&sighand->siglock); | |
1da177e4 LT |
1131 | } |
1132 | ||
1133 | do_exit(exit_code); | |
1134 | /* NOTREACHED */ | |
1135 | } | |
1136 | ||
1137 | /* | |
1138 | * this kills every thread in the thread group. Note that any externally | |
1139 | * wait4()-ing process will get the correct exit code - even if this | |
1140 | * thread is not the thread group leader. | |
1141 | */ | |
754fe8d2 | 1142 | SYSCALL_DEFINE1(exit_group, int, error_code) |
1da177e4 LT |
1143 | { |
1144 | do_group_exit((error_code & 0xff) << 8); | |
2ed7c03e HC |
1145 | /* NOTREACHED */ |
1146 | return 0; | |
1da177e4 LT |
1147 | } |
1148 | ||
9e8ae01d ON |
1149 | struct wait_opts { |
1150 | enum pid_type wo_type; | |
9e8ae01d | 1151 | int wo_flags; |
e1eb1ebc | 1152 | struct pid *wo_pid; |
9e8ae01d ON |
1153 | |
1154 | struct siginfo __user *wo_info; | |
1155 | int __user *wo_stat; | |
1156 | struct rusage __user *wo_rusage; | |
1157 | ||
0b7570e7 | 1158 | wait_queue_t child_wait; |
9e8ae01d ON |
1159 | int notask_error; |
1160 | }; | |
1161 | ||
989264f4 ON |
1162 | static inline |
1163 | struct pid *task_pid_type(struct task_struct *task, enum pid_type type) | |
161550d7 | 1164 | { |
989264f4 ON |
1165 | if (type != PIDTYPE_PID) |
1166 | task = task->group_leader; | |
1167 | return task->pids[type].pid; | |
161550d7 EB |
1168 | } |
1169 | ||
989264f4 | 1170 | static int eligible_pid(struct wait_opts *wo, struct task_struct *p) |
1da177e4 | 1171 | { |
5c01ba49 ON |
1172 | return wo->wo_type == PIDTYPE_MAX || |
1173 | task_pid_type(p, wo->wo_type) == wo->wo_pid; | |
1174 | } | |
1da177e4 | 1175 | |
5c01ba49 ON |
1176 | static int eligible_child(struct wait_opts *wo, struct task_struct *p) |
1177 | { | |
1178 | if (!eligible_pid(wo, p)) | |
1179 | return 0; | |
1da177e4 LT |
1180 | /* Wait for all children (clone and not) if __WALL is set; |
1181 | * otherwise, wait for clone children *only* if __WCLONE is | |
1182 | * set; otherwise, wait for non-clone children *only*. (Note: | |
1183 | * A "clone" child here is one that reports to its parent | |
1184 | * using a signal other than SIGCHLD.) */ | |
9e8ae01d ON |
1185 | if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE)) |
1186 | && !(wo->wo_flags & __WALL)) | |
1da177e4 | 1187 | return 0; |
1da177e4 | 1188 | |
14dd0b81 | 1189 | return 1; |
1da177e4 LT |
1190 | } |
1191 | ||
9e8ae01d ON |
1192 | static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p, |
1193 | pid_t pid, uid_t uid, int why, int status) | |
1da177e4 | 1194 | { |
9e8ae01d ON |
1195 | struct siginfo __user *infop; |
1196 | int retval = wo->wo_rusage | |
1197 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; | |
36c8b586 | 1198 | |
1da177e4 | 1199 | put_task_struct(p); |
9e8ae01d | 1200 | infop = wo->wo_info; |
b6fe2d11 VM |
1201 | if (infop) { |
1202 | if (!retval) | |
1203 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1204 | if (!retval) | |
1205 | retval = put_user(0, &infop->si_errno); | |
1206 | if (!retval) | |
1207 | retval = put_user((short)why, &infop->si_code); | |
1208 | if (!retval) | |
1209 | retval = put_user(pid, &infop->si_pid); | |
1210 | if (!retval) | |
1211 | retval = put_user(uid, &infop->si_uid); | |
1212 | if (!retval) | |
1213 | retval = put_user(status, &infop->si_status); | |
1214 | } | |
1da177e4 LT |
1215 | if (!retval) |
1216 | retval = pid; | |
1217 | return retval; | |
1218 | } | |
1219 | ||
1220 | /* | |
1221 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold | |
1222 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1223 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1224 | * released the lock and the system call should return. | |
1225 | */ | |
9e8ae01d | 1226 | static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) |
1da177e4 LT |
1227 | { |
1228 | unsigned long state; | |
2f4e6e2a | 1229 | int retval, status, traced; |
6c5f3e7b | 1230 | pid_t pid = task_pid_vnr(p); |
43e13cc1 | 1231 | uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
9e8ae01d | 1232 | struct siginfo __user *infop; |
1da177e4 | 1233 | |
9e8ae01d | 1234 | if (!likely(wo->wo_flags & WEXITED)) |
98abed02 RM |
1235 | return 0; |
1236 | ||
9e8ae01d | 1237 | if (unlikely(wo->wo_flags & WNOWAIT)) { |
1da177e4 | 1238 | int exit_code = p->exit_code; |
f3abd4f9 | 1239 | int why; |
1da177e4 | 1240 | |
1da177e4 LT |
1241 | get_task_struct(p); |
1242 | read_unlock(&tasklist_lock); | |
1243 | if ((exit_code & 0x7f) == 0) { | |
1244 | why = CLD_EXITED; | |
1245 | status = exit_code >> 8; | |
1246 | } else { | |
1247 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1248 | status = exit_code & 0x7f; | |
1249 | } | |
9e8ae01d | 1250 | return wait_noreap_copyout(wo, p, pid, uid, why, status); |
1da177e4 LT |
1251 | } |
1252 | ||
1253 | /* | |
1254 | * Try to move the task's state to DEAD | |
1255 | * only one thread is allowed to do this: | |
1256 | */ | |
1257 | state = xchg(&p->exit_state, EXIT_DEAD); | |
1258 | if (state != EXIT_ZOMBIE) { | |
1259 | BUG_ON(state != EXIT_DEAD); | |
1260 | return 0; | |
1261 | } | |
1da177e4 | 1262 | |
53b6f9fb | 1263 | traced = ptrace_reparented(p); |
befca967 ON |
1264 | /* |
1265 | * It can be ptraced but not reparented, check | |
e550f14d | 1266 | * thread_group_leader() to filter out sub-threads. |
befca967 | 1267 | */ |
e550f14d | 1268 | if (likely(!traced) && thread_group_leader(p)) { |
3795e161 JJ |
1269 | struct signal_struct *psig; |
1270 | struct signal_struct *sig; | |
1f10206c | 1271 | unsigned long maxrss; |
0cf55e1e | 1272 | cputime_t tgutime, tgstime; |
3795e161 | 1273 | |
1da177e4 LT |
1274 | /* |
1275 | * The resource counters for the group leader are in its | |
1276 | * own task_struct. Those for dead threads in the group | |
1277 | * are in its signal_struct, as are those for the child | |
1278 | * processes it has previously reaped. All these | |
1279 | * accumulate in the parent's signal_struct c* fields. | |
1280 | * | |
1281 | * We don't bother to take a lock here to protect these | |
1282 | * p->signal fields, because they are only touched by | |
1283 | * __exit_signal, which runs with tasklist_lock | |
1284 | * write-locked anyway, and so is excluded here. We do | |
d1e98f42 | 1285 | * need to protect the access to parent->signal fields, |
1da177e4 LT |
1286 | * as other threads in the parent group can be right |
1287 | * here reaping other children at the same time. | |
0cf55e1e HS |
1288 | * |
1289 | * We use thread_group_times() to get times for the thread | |
1290 | * group, which consolidates times for all threads in the | |
1291 | * group including the group leader. | |
1da177e4 | 1292 | */ |
0cf55e1e | 1293 | thread_group_times(p, &tgutime, &tgstime); |
d1e98f42 ON |
1294 | spin_lock_irq(&p->real_parent->sighand->siglock); |
1295 | psig = p->real_parent->signal; | |
3795e161 | 1296 | sig = p->signal; |
64861634 MS |
1297 | psig->cutime += tgutime + sig->cutime; |
1298 | psig->cstime += tgstime + sig->cstime; | |
1299 | psig->cgtime += p->gtime + sig->gtime + sig->cgtime; | |
3795e161 JJ |
1300 | psig->cmin_flt += |
1301 | p->min_flt + sig->min_flt + sig->cmin_flt; | |
1302 | psig->cmaj_flt += | |
1303 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; | |
1304 | psig->cnvcsw += | |
1305 | p->nvcsw + sig->nvcsw + sig->cnvcsw; | |
1306 | psig->cnivcsw += | |
1307 | p->nivcsw + sig->nivcsw + sig->cnivcsw; | |
6eaeeaba ED |
1308 | psig->cinblock += |
1309 | task_io_get_inblock(p) + | |
1310 | sig->inblock + sig->cinblock; | |
1311 | psig->coublock += | |
1312 | task_io_get_oublock(p) + | |
1313 | sig->oublock + sig->coublock; | |
1f10206c JP |
1314 | maxrss = max(sig->maxrss, sig->cmaxrss); |
1315 | if (psig->cmaxrss < maxrss) | |
1316 | psig->cmaxrss = maxrss; | |
5995477a AR |
1317 | task_io_accounting_add(&psig->ioac, &p->ioac); |
1318 | task_io_accounting_add(&psig->ioac, &sig->ioac); | |
d1e98f42 | 1319 | spin_unlock_irq(&p->real_parent->sighand->siglock); |
1da177e4 LT |
1320 | } |
1321 | ||
1322 | /* | |
1323 | * Now we are sure this task is interesting, and no other | |
1324 | * thread can reap it because we set its state to EXIT_DEAD. | |
1325 | */ | |
1326 | read_unlock(&tasklist_lock); | |
1327 | ||
9e8ae01d ON |
1328 | retval = wo->wo_rusage |
1329 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; | |
1da177e4 LT |
1330 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) |
1331 | ? p->signal->group_exit_code : p->exit_code; | |
9e8ae01d ON |
1332 | if (!retval && wo->wo_stat) |
1333 | retval = put_user(status, wo->wo_stat); | |
1334 | ||
1335 | infop = wo->wo_info; | |
1da177e4 LT |
1336 | if (!retval && infop) |
1337 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1338 | if (!retval && infop) | |
1339 | retval = put_user(0, &infop->si_errno); | |
1340 | if (!retval && infop) { | |
1341 | int why; | |
1342 | ||
1343 | if ((status & 0x7f) == 0) { | |
1344 | why = CLD_EXITED; | |
1345 | status >>= 8; | |
1346 | } else { | |
1347 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1348 | status &= 0x7f; | |
1349 | } | |
1350 | retval = put_user((short)why, &infop->si_code); | |
1351 | if (!retval) | |
1352 | retval = put_user(status, &infop->si_status); | |
1353 | } | |
1354 | if (!retval && infop) | |
3a515e4a | 1355 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1356 | if (!retval && infop) |
c69e8d9c | 1357 | retval = put_user(uid, &infop->si_uid); |
2f4e6e2a | 1358 | if (!retval) |
3a515e4a | 1359 | retval = pid; |
2f4e6e2a ON |
1360 | |
1361 | if (traced) { | |
1da177e4 | 1362 | write_lock_irq(&tasklist_lock); |
2f4e6e2a ON |
1363 | /* We dropped tasklist, ptracer could die and untrace */ |
1364 | ptrace_unlink(p); | |
1365 | /* | |
86773473 ON |
1366 | * If this is not a sub-thread, notify the parent. |
1367 | * If parent wants a zombie, don't release it now. | |
2f4e6e2a | 1368 | */ |
86773473 ON |
1369 | if (thread_group_leader(p) && |
1370 | !do_notify_parent(p, p->exit_signal)) { | |
1371 | p->exit_state = EXIT_ZOMBIE; | |
1372 | p = NULL; | |
1da177e4 LT |
1373 | } |
1374 | write_unlock_irq(&tasklist_lock); | |
1375 | } | |
1376 | if (p != NULL) | |
1377 | release_task(p); | |
2f4e6e2a | 1378 | |
1da177e4 LT |
1379 | return retval; |
1380 | } | |
1381 | ||
90bc8d8b ON |
1382 | static int *task_stopped_code(struct task_struct *p, bool ptrace) |
1383 | { | |
1384 | if (ptrace) { | |
544b2c91 TH |
1385 | if (task_is_stopped_or_traced(p) && |
1386 | !(p->jobctl & JOBCTL_LISTENING)) | |
90bc8d8b ON |
1387 | return &p->exit_code; |
1388 | } else { | |
1389 | if (p->signal->flags & SIGNAL_STOP_STOPPED) | |
1390 | return &p->signal->group_exit_code; | |
1391 | } | |
1392 | return NULL; | |
1393 | } | |
1394 | ||
19e27463 TH |
1395 | /** |
1396 | * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED | |
1397 | * @wo: wait options | |
1398 | * @ptrace: is the wait for ptrace | |
1399 | * @p: task to wait for | |
1400 | * | |
1401 | * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED. | |
1402 | * | |
1403 | * CONTEXT: | |
1404 | * read_lock(&tasklist_lock), which is released if return value is | |
1405 | * non-zero. Also, grabs and releases @p->sighand->siglock. | |
1406 | * | |
1407 | * RETURNS: | |
1408 | * 0 if wait condition didn't exist and search for other wait conditions | |
1409 | * should continue. Non-zero return, -errno on failure and @p's pid on | |
1410 | * success, implies that tasklist_lock is released and wait condition | |
1411 | * search should terminate. | |
1da177e4 | 1412 | */ |
9e8ae01d ON |
1413 | static int wait_task_stopped(struct wait_opts *wo, |
1414 | int ptrace, struct task_struct *p) | |
1da177e4 | 1415 | { |
9e8ae01d | 1416 | struct siginfo __user *infop; |
90bc8d8b | 1417 | int retval, exit_code, *p_code, why; |
ee7c82da | 1418 | uid_t uid = 0; /* unneeded, required by compiler */ |
c8950783 | 1419 | pid_t pid; |
1da177e4 | 1420 | |
47918025 ON |
1421 | /* |
1422 | * Traditionally we see ptrace'd stopped tasks regardless of options. | |
1423 | */ | |
9e8ae01d | 1424 | if (!ptrace && !(wo->wo_flags & WUNTRACED)) |
98abed02 RM |
1425 | return 0; |
1426 | ||
19e27463 TH |
1427 | if (!task_stopped_code(p, ptrace)) |
1428 | return 0; | |
1429 | ||
ee7c82da ON |
1430 | exit_code = 0; |
1431 | spin_lock_irq(&p->sighand->siglock); | |
1432 | ||
90bc8d8b ON |
1433 | p_code = task_stopped_code(p, ptrace); |
1434 | if (unlikely(!p_code)) | |
ee7c82da ON |
1435 | goto unlock_sig; |
1436 | ||
90bc8d8b | 1437 | exit_code = *p_code; |
ee7c82da ON |
1438 | if (!exit_code) |
1439 | goto unlock_sig; | |
1440 | ||
9e8ae01d | 1441 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
90bc8d8b | 1442 | *p_code = 0; |
ee7c82da | 1443 | |
8ca937a6 | 1444 | uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
ee7c82da ON |
1445 | unlock_sig: |
1446 | spin_unlock_irq(&p->sighand->siglock); | |
1447 | if (!exit_code) | |
1da177e4 LT |
1448 | return 0; |
1449 | ||
1450 | /* | |
1451 | * Now we are pretty sure this task is interesting. | |
1452 | * Make sure it doesn't get reaped out from under us while we | |
1453 | * give up the lock and then examine it below. We don't want to | |
1454 | * keep holding onto the tasklist_lock while we call getrusage and | |
1455 | * possibly take page faults for user memory. | |
1456 | */ | |
1457 | get_task_struct(p); | |
6c5f3e7b | 1458 | pid = task_pid_vnr(p); |
f470021a | 1459 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED; |
1da177e4 LT |
1460 | read_unlock(&tasklist_lock); |
1461 | ||
9e8ae01d ON |
1462 | if (unlikely(wo->wo_flags & WNOWAIT)) |
1463 | return wait_noreap_copyout(wo, p, pid, uid, why, exit_code); | |
1464 | ||
1465 | retval = wo->wo_rusage | |
1466 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; | |
1467 | if (!retval && wo->wo_stat) | |
1468 | retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat); | |
1da177e4 | 1469 | |
9e8ae01d | 1470 | infop = wo->wo_info; |
1da177e4 LT |
1471 | if (!retval && infop) |
1472 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1473 | if (!retval && infop) | |
1474 | retval = put_user(0, &infop->si_errno); | |
1475 | if (!retval && infop) | |
6efcae46 | 1476 | retval = put_user((short)why, &infop->si_code); |
1da177e4 LT |
1477 | if (!retval && infop) |
1478 | retval = put_user(exit_code, &infop->si_status); | |
1479 | if (!retval && infop) | |
c8950783 | 1480 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1481 | if (!retval && infop) |
ee7c82da | 1482 | retval = put_user(uid, &infop->si_uid); |
1da177e4 | 1483 | if (!retval) |
c8950783 | 1484 | retval = pid; |
1da177e4 LT |
1485 | put_task_struct(p); |
1486 | ||
1487 | BUG_ON(!retval); | |
1488 | return retval; | |
1489 | } | |
1490 | ||
1491 | /* | |
1492 | * Handle do_wait work for one task in a live, non-stopped state. | |
1493 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1494 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1495 | * released the lock and the system call should return. | |
1496 | */ | |
9e8ae01d | 1497 | static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) |
1da177e4 LT |
1498 | { |
1499 | int retval; | |
1500 | pid_t pid; | |
1501 | uid_t uid; | |
1502 | ||
9e8ae01d | 1503 | if (!unlikely(wo->wo_flags & WCONTINUED)) |
98abed02 RM |
1504 | return 0; |
1505 | ||
1da177e4 LT |
1506 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) |
1507 | return 0; | |
1508 | ||
1509 | spin_lock_irq(&p->sighand->siglock); | |
1510 | /* Re-check with the lock held. */ | |
1511 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { | |
1512 | spin_unlock_irq(&p->sighand->siglock); | |
1513 | return 0; | |
1514 | } | |
9e8ae01d | 1515 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
1da177e4 | 1516 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; |
8ca937a6 | 1517 | uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
1da177e4 LT |
1518 | spin_unlock_irq(&p->sighand->siglock); |
1519 | ||
6c5f3e7b | 1520 | pid = task_pid_vnr(p); |
1da177e4 LT |
1521 | get_task_struct(p); |
1522 | read_unlock(&tasklist_lock); | |
1523 | ||
9e8ae01d ON |
1524 | if (!wo->wo_info) { |
1525 | retval = wo->wo_rusage | |
1526 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; | |
1da177e4 | 1527 | put_task_struct(p); |
9e8ae01d ON |
1528 | if (!retval && wo->wo_stat) |
1529 | retval = put_user(0xffff, wo->wo_stat); | |
1da177e4 | 1530 | if (!retval) |
3a515e4a | 1531 | retval = pid; |
1da177e4 | 1532 | } else { |
9e8ae01d ON |
1533 | retval = wait_noreap_copyout(wo, p, pid, uid, |
1534 | CLD_CONTINUED, SIGCONT); | |
1da177e4 LT |
1535 | BUG_ON(retval == 0); |
1536 | } | |
1537 | ||
1538 | return retval; | |
1539 | } | |
1540 | ||
98abed02 RM |
1541 | /* |
1542 | * Consider @p for a wait by @parent. | |
1543 | * | |
9e8ae01d | 1544 | * -ECHILD should be in ->notask_error before the first call. |
98abed02 RM |
1545 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1546 | * Returns zero if the search for a child should continue; | |
9e8ae01d | 1547 | * then ->notask_error is 0 if @p is an eligible child, |
14dd0b81 | 1548 | * or another error from security_task_wait(), or still -ECHILD. |
98abed02 | 1549 | */ |
b6e763f0 ON |
1550 | static int wait_consider_task(struct wait_opts *wo, int ptrace, |
1551 | struct task_struct *p) | |
98abed02 | 1552 | { |
9e8ae01d | 1553 | int ret = eligible_child(wo, p); |
14dd0b81 | 1554 | if (!ret) |
98abed02 RM |
1555 | return ret; |
1556 | ||
a2322e1d | 1557 | ret = security_task_wait(p); |
14dd0b81 RM |
1558 | if (unlikely(ret < 0)) { |
1559 | /* | |
1560 | * If we have not yet seen any eligible child, | |
1561 | * then let this error code replace -ECHILD. | |
1562 | * A permission error will give the user a clue | |
1563 | * to look for security policy problems, rather | |
1564 | * than for mysterious wait bugs. | |
1565 | */ | |
9e8ae01d ON |
1566 | if (wo->notask_error) |
1567 | wo->notask_error = ret; | |
78a3d9d5 | 1568 | return 0; |
14dd0b81 RM |
1569 | } |
1570 | ||
823b018e | 1571 | /* dead body doesn't have much to contribute */ |
50b8d257 ON |
1572 | if (unlikely(p->exit_state == EXIT_DEAD)) { |
1573 | /* | |
1574 | * But do not ignore this task until the tracer does | |
1575 | * wait_task_zombie()->do_notify_parent(). | |
1576 | */ | |
1577 | if (likely(!ptrace) && unlikely(ptrace_reparented(p))) | |
1578 | wo->notask_error = 0; | |
823b018e | 1579 | return 0; |
50b8d257 | 1580 | } |
823b018e | 1581 | |
45cb24a1 TH |
1582 | /* slay zombie? */ |
1583 | if (p->exit_state == EXIT_ZOMBIE) { | |
f470021a | 1584 | /* |
45cb24a1 TH |
1585 | * A zombie ptracee is only visible to its ptracer. |
1586 | * Notification and reaping will be cascaded to the real | |
1587 | * parent when the ptracer detaches. | |
f470021a | 1588 | */ |
d21142ec | 1589 | if (likely(!ptrace) && unlikely(p->ptrace)) { |
45cb24a1 TH |
1590 | /* it will become visible, clear notask_error */ |
1591 | wo->notask_error = 0; | |
1592 | return 0; | |
1593 | } | |
f470021a | 1594 | |
9b84cca2 TH |
1595 | /* we don't reap group leaders with subthreads */ |
1596 | if (!delay_group_leader(p)) | |
1597 | return wait_task_zombie(wo, p); | |
98abed02 | 1598 | |
f470021a | 1599 | /* |
9b84cca2 TH |
1600 | * Allow access to stopped/continued state via zombie by |
1601 | * falling through. Clearing of notask_error is complex. | |
1602 | * | |
1603 | * When !@ptrace: | |
1604 | * | |
1605 | * If WEXITED is set, notask_error should naturally be | |
1606 | * cleared. If not, subset of WSTOPPED|WCONTINUED is set, | |
1607 | * so, if there are live subthreads, there are events to | |
1608 | * wait for. If all subthreads are dead, it's still safe | |
1609 | * to clear - this function will be called again in finite | |
1610 | * amount time once all the subthreads are released and | |
1611 | * will then return without clearing. | |
1612 | * | |
1613 | * When @ptrace: | |
1614 | * | |
1615 | * Stopped state is per-task and thus can't change once the | |
1616 | * target task dies. Only continued and exited can happen. | |
1617 | * Clear notask_error if WCONTINUED | WEXITED. | |
1618 | */ | |
1619 | if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED))) | |
1620 | wo->notask_error = 0; | |
1621 | } else { | |
45cb24a1 TH |
1622 | /* |
1623 | * If @p is ptraced by a task in its real parent's group, | |
1624 | * hide group stop/continued state when looking at @p as | |
1625 | * the real parent; otherwise, a single stop can be | |
1626 | * reported twice as group and ptrace stops. | |
1627 | * | |
1628 | * If a ptracer wants to distinguish the two events for its | |
1629 | * own children, it should create a separate process which | |
1630 | * takes the role of real parent. | |
1631 | */ | |
479bf98c | 1632 | if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p)) |
45cb24a1 TH |
1633 | return 0; |
1634 | ||
9b84cca2 TH |
1635 | /* |
1636 | * @p is alive and it's gonna stop, continue or exit, so | |
1637 | * there always is something to wait for. | |
f470021a | 1638 | */ |
9e8ae01d | 1639 | wo->notask_error = 0; |
f470021a RM |
1640 | } |
1641 | ||
98abed02 | 1642 | /* |
45cb24a1 TH |
1643 | * Wait for stopped. Depending on @ptrace, different stopped state |
1644 | * is used and the two don't interact with each other. | |
98abed02 | 1645 | */ |
19e27463 TH |
1646 | ret = wait_task_stopped(wo, ptrace, p); |
1647 | if (ret) | |
1648 | return ret; | |
98abed02 RM |
1649 | |
1650 | /* | |
45cb24a1 TH |
1651 | * Wait for continued. There's only one continued state and the |
1652 | * ptracer can consume it which can confuse the real parent. Don't | |
1653 | * use WCONTINUED from ptracer. You don't need or want it. | |
98abed02 | 1654 | */ |
9e8ae01d | 1655 | return wait_task_continued(wo, p); |
98abed02 RM |
1656 | } |
1657 | ||
1658 | /* | |
1659 | * Do the work of do_wait() for one thread in the group, @tsk. | |
1660 | * | |
9e8ae01d | 1661 | * -ECHILD should be in ->notask_error before the first call. |
98abed02 RM |
1662 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1663 | * Returns zero if the search for a child should continue; then | |
9e8ae01d | 1664 | * ->notask_error is 0 if there were any eligible children, |
14dd0b81 | 1665 | * or another error from security_task_wait(), or still -ECHILD. |
98abed02 | 1666 | */ |
9e8ae01d | 1667 | static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk) |
98abed02 RM |
1668 | { |
1669 | struct task_struct *p; | |
1670 | ||
1671 | list_for_each_entry(p, &tsk->children, sibling) { | |
9cd80bbb ON |
1672 | int ret = wait_consider_task(wo, 0, p); |
1673 | if (ret) | |
1674 | return ret; | |
98abed02 RM |
1675 | } |
1676 | ||
1677 | return 0; | |
1678 | } | |
1679 | ||
9e8ae01d | 1680 | static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk) |
98abed02 RM |
1681 | { |
1682 | struct task_struct *p; | |
1683 | ||
f470021a | 1684 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { |
b6e763f0 | 1685 | int ret = wait_consider_task(wo, 1, p); |
f470021a | 1686 | if (ret) |
98abed02 | 1687 | return ret; |
98abed02 RM |
1688 | } |
1689 | ||
1690 | return 0; | |
1691 | } | |
1692 | ||
0b7570e7 ON |
1693 | static int child_wait_callback(wait_queue_t *wait, unsigned mode, |
1694 | int sync, void *key) | |
1695 | { | |
1696 | struct wait_opts *wo = container_of(wait, struct wait_opts, | |
1697 | child_wait); | |
1698 | struct task_struct *p = key; | |
1699 | ||
5c01ba49 | 1700 | if (!eligible_pid(wo, p)) |
0b7570e7 ON |
1701 | return 0; |
1702 | ||
b4fe5182 ON |
1703 | if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent) |
1704 | return 0; | |
1705 | ||
0b7570e7 ON |
1706 | return default_wake_function(wait, mode, sync, key); |
1707 | } | |
1708 | ||
a7f0765e ON |
1709 | void __wake_up_parent(struct task_struct *p, struct task_struct *parent) |
1710 | { | |
0b7570e7 ON |
1711 | __wake_up_sync_key(&parent->signal->wait_chldexit, |
1712 | TASK_INTERRUPTIBLE, 1, p); | |
a7f0765e ON |
1713 | } |
1714 | ||
9e8ae01d | 1715 | static long do_wait(struct wait_opts *wo) |
1da177e4 | 1716 | { |
1da177e4 | 1717 | struct task_struct *tsk; |
98abed02 | 1718 | int retval; |
1da177e4 | 1719 | |
9e8ae01d | 1720 | trace_sched_process_wait(wo->wo_pid); |
0a16b607 | 1721 | |
0b7570e7 ON |
1722 | init_waitqueue_func_entry(&wo->child_wait, child_wait_callback); |
1723 | wo->child_wait.private = current; | |
1724 | add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); | |
1da177e4 | 1725 | repeat: |
98abed02 RM |
1726 | /* |
1727 | * If there is nothing that can match our critiera just get out. | |
9e8ae01d ON |
1728 | * We will clear ->notask_error to zero if we see any child that |
1729 | * might later match our criteria, even if we are not able to reap | |
1730 | * it yet. | |
98abed02 | 1731 | */ |
64a16caf | 1732 | wo->notask_error = -ECHILD; |
9e8ae01d ON |
1733 | if ((wo->wo_type < PIDTYPE_MAX) && |
1734 | (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type]))) | |
64a16caf | 1735 | goto notask; |
161550d7 | 1736 | |
f95d39d1 | 1737 | set_current_state(TASK_INTERRUPTIBLE); |
1da177e4 LT |
1738 | read_lock(&tasklist_lock); |
1739 | tsk = current; | |
1740 | do { | |
64a16caf ON |
1741 | retval = do_wait_thread(wo, tsk); |
1742 | if (retval) | |
1743 | goto end; | |
9e8ae01d | 1744 | |
64a16caf ON |
1745 | retval = ptrace_do_wait(wo, tsk); |
1746 | if (retval) | |
98abed02 | 1747 | goto end; |
98abed02 | 1748 | |
9e8ae01d | 1749 | if (wo->wo_flags & __WNOTHREAD) |
1da177e4 | 1750 | break; |
a3f6dfb7 | 1751 | } while_each_thread(current, tsk); |
1da177e4 | 1752 | read_unlock(&tasklist_lock); |
f2cc3eb1 | 1753 | |
64a16caf | 1754 | notask: |
9e8ae01d ON |
1755 | retval = wo->notask_error; |
1756 | if (!retval && !(wo->wo_flags & WNOHANG)) { | |
1da177e4 | 1757 | retval = -ERESTARTSYS; |
98abed02 RM |
1758 | if (!signal_pending(current)) { |
1759 | schedule(); | |
1760 | goto repeat; | |
1761 | } | |
1da177e4 | 1762 | } |
1da177e4 | 1763 | end: |
f95d39d1 | 1764 | __set_current_state(TASK_RUNNING); |
0b7570e7 | 1765 | remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); |
1da177e4 LT |
1766 | return retval; |
1767 | } | |
1768 | ||
17da2bd9 HC |
1769 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, |
1770 | infop, int, options, struct rusage __user *, ru) | |
1da177e4 | 1771 | { |
9e8ae01d | 1772 | struct wait_opts wo; |
161550d7 EB |
1773 | struct pid *pid = NULL; |
1774 | enum pid_type type; | |
1da177e4 LT |
1775 | long ret; |
1776 | ||
1777 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) | |
1778 | return -EINVAL; | |
1779 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) | |
1780 | return -EINVAL; | |
1781 | ||
1782 | switch (which) { | |
1783 | case P_ALL: | |
161550d7 | 1784 | type = PIDTYPE_MAX; |
1da177e4 LT |
1785 | break; |
1786 | case P_PID: | |
161550d7 EB |
1787 | type = PIDTYPE_PID; |
1788 | if (upid <= 0) | |
1da177e4 LT |
1789 | return -EINVAL; |
1790 | break; | |
1791 | case P_PGID: | |
161550d7 EB |
1792 | type = PIDTYPE_PGID; |
1793 | if (upid <= 0) | |
1da177e4 | 1794 | return -EINVAL; |
1da177e4 LT |
1795 | break; |
1796 | default: | |
1797 | return -EINVAL; | |
1798 | } | |
1799 | ||
161550d7 EB |
1800 | if (type < PIDTYPE_MAX) |
1801 | pid = find_get_pid(upid); | |
9e8ae01d ON |
1802 | |
1803 | wo.wo_type = type; | |
1804 | wo.wo_pid = pid; | |
1805 | wo.wo_flags = options; | |
1806 | wo.wo_info = infop; | |
1807 | wo.wo_stat = NULL; | |
1808 | wo.wo_rusage = ru; | |
1809 | ret = do_wait(&wo); | |
dfe16dfa VM |
1810 | |
1811 | if (ret > 0) { | |
1812 | ret = 0; | |
1813 | } else if (infop) { | |
1814 | /* | |
1815 | * For a WNOHANG return, clear out all the fields | |
1816 | * we would set so the user can easily tell the | |
1817 | * difference. | |
1818 | */ | |
1819 | if (!ret) | |
1820 | ret = put_user(0, &infop->si_signo); | |
1821 | if (!ret) | |
1822 | ret = put_user(0, &infop->si_errno); | |
1823 | if (!ret) | |
1824 | ret = put_user(0, &infop->si_code); | |
1825 | if (!ret) | |
1826 | ret = put_user(0, &infop->si_pid); | |
1827 | if (!ret) | |
1828 | ret = put_user(0, &infop->si_uid); | |
1829 | if (!ret) | |
1830 | ret = put_user(0, &infop->si_status); | |
1831 | } | |
1832 | ||
161550d7 | 1833 | put_pid(pid); |
1da177e4 LT |
1834 | |
1835 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1836 | asmlinkage_protect(5, ret, which, upid, infop, options, ru); |
1da177e4 LT |
1837 | return ret; |
1838 | } | |
1839 | ||
754fe8d2 HC |
1840 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, |
1841 | int, options, struct rusage __user *, ru) | |
1da177e4 | 1842 | { |
9e8ae01d | 1843 | struct wait_opts wo; |
161550d7 EB |
1844 | struct pid *pid = NULL; |
1845 | enum pid_type type; | |
1da177e4 LT |
1846 | long ret; |
1847 | ||
1848 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| | |
1849 | __WNOTHREAD|__WCLONE|__WALL)) | |
1850 | return -EINVAL; | |
161550d7 EB |
1851 | |
1852 | if (upid == -1) | |
1853 | type = PIDTYPE_MAX; | |
1854 | else if (upid < 0) { | |
1855 | type = PIDTYPE_PGID; | |
1856 | pid = find_get_pid(-upid); | |
1857 | } else if (upid == 0) { | |
1858 | type = PIDTYPE_PGID; | |
2ae448ef | 1859 | pid = get_task_pid(current, PIDTYPE_PGID); |
161550d7 EB |
1860 | } else /* upid > 0 */ { |
1861 | type = PIDTYPE_PID; | |
1862 | pid = find_get_pid(upid); | |
1863 | } | |
1864 | ||
9e8ae01d ON |
1865 | wo.wo_type = type; |
1866 | wo.wo_pid = pid; | |
1867 | wo.wo_flags = options | WEXITED; | |
1868 | wo.wo_info = NULL; | |
1869 | wo.wo_stat = stat_addr; | |
1870 | wo.wo_rusage = ru; | |
1871 | ret = do_wait(&wo); | |
161550d7 | 1872 | put_pid(pid); |
1da177e4 LT |
1873 | |
1874 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1875 | asmlinkage_protect(4, ret, upid, stat_addr, options, ru); |
1da177e4 LT |
1876 | return ret; |
1877 | } | |
1878 | ||
1879 | #ifdef __ARCH_WANT_SYS_WAITPID | |
1880 | ||
1881 | /* | |
1882 | * sys_waitpid() remains for compatibility. waitpid() should be | |
1883 | * implemented by calling sys_wait4() from libc.a. | |
1884 | */ | |
17da2bd9 | 1885 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) |
1da177e4 LT |
1886 | { |
1887 | return sys_wait4(pid, stat_addr, options, NULL); | |
1888 | } | |
1889 | ||
1890 | #endif |