| 1 | |
| 2 | |
| 3 | * linux/kernel/exit.c
|
| 4 | *
|
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds
|
| 6 |
|
| 7 |
|
| 8 | #include <linux/mm.h>
|
| 9 | #include <linux/slab.h>
|
| 10 | #include <linux/sched/autogroup.h>
|
| 11 | #include <linux/sched/mm.h>
|
| 12 | #include <linux/sched/stat.h>
|
| 13 | #include <linux/sched/task.h>
|
| 14 | #include <linux/sched/task_stack.h>
|
| 15 | #include <linux/sched/cputime.h>
|
| 16 | #include <linux/interrupt.h>
|
| 17 | #include <linux/module.h>
|
| 18 | #include <linux/capability.h>
|
| 19 | #include <linux/completion.h>
|
| 20 | #include <linux/personality.h>
|
| 21 | #include <linux/tty.h>
|
| 22 | #include <linux/iocontext.h>
|
| 23 | #include <linux/key.h>
|
| 24 | #include <linux/cpu.h>
|
| 25 | #include <linux/acct.h>
|
| 26 | #include <linux/tsacct_kern.h>
|
| 27 | #include <linux/file.h>
|
| 28 | #include <linux/fdtable.h>
|
| 29 | #include <linux/freezer.h>
|
| 30 | #include <linux/binfmts.h>
|
| 31 | #include <linux/nsproxy.h>
|
| 32 | #include <linux/pid_namespace.h>
|
| 33 | #include <linux/ptrace.h>
|
| 34 | #include <linux/profile.h>
|
| 35 | #include <linux/mount.h>
|
| 36 | #include <linux/proc_fs.h>
|
| 37 | #include <linux/kthread.h>
|
| 38 | #include <linux/mempolicy.h>
|
| 39 | #include <linux/taskstats_kern.h>
|
| 40 | #include <linux/delayacct.h>
|
| 41 | #include <linux/cgroup.h>
|
| 42 | #include <linux/syscalls.h>
|
| 43 | #include <linux/signal.h>
|
| 44 | #include <linux/posix-timers.h>
|
| 45 | #include <linux/cn_proc.h>
|
| 46 | #include <linux/mutex.h>
|
| 47 | #include <linux/futex.h>
|
| 48 | #include <linux/pipe_fs_i.h>
|
| 49 | #include <linux/audit.h>
|
| 50 | #include <linux/resource.h>
|
| 51 | #include <linux/task_io_accounting_ops.h>
|
| 52 | #include <linux/blkdev.h>
|
| 53 | #include <linux/task_work.h>
|
| 54 | #include <linux/fs_struct.h>
|
| 55 | #include <linux/init_task.h>
|
| 56 | #include <linux/perf_event.h>
|
| 57 | #include <trace/events/sched.h>
|
| 58 | #include <linux/hw_breakpoint.h>
|
| 59 | #include <linux/oom.h>
|
| 60 | #include <linux/writeback.h>
|
| 61 | #include <linux/shm.h>
|
| 62 | #include <linux/kcov.h>
|
| 63 | #include <linux/random.h>
|
| 64 | #include <linux/rcuwait.h>
|
| 65 | #include <linux/compat.h>
|
| 66 | #include <linux/io_uring.h>
|
| 67 | #include <linux/kprobes.h>
|
| 68 | #include <linux/rethook.h>
|
| 69 |
|
| 70 | #include <linux/uaccess.h>
|
| 71 | #include <asm/unistd.h>
|
| 72 | #include <asm/mmu_context.h>
|
| 73 |
|
| 74 | static void __unhash_process(struct task_struct *p, bool group_dead)
|
| 75 | {
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| 76 | nr_threads--;
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| 77 | detach_pid(p, PIDTYPE_PID);
|
| 78 | if (group_dead) {
|
| 79 | detach_pid(p, PIDTYPE_TGID);
|
| 80 | detach_pid(p, PIDTYPE_PGID);
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| 81 | detach_pid(p, PIDTYPE_SID);
|
| 82 |
|
| 83 | list_del_rcu(&p->tasks);
|
| 84 | list_del_init(&p->sibling);
|
| 85 | __this_cpu_dec(process_counts);
|
| 86 | }
|
| 87 | list_del_rcu(&p->thread_group);
|
| 88 | list_del_rcu(&p->thread_node);
|
| 89 | }
|
| 90 |
|
| 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;
|
| 97 | bool group_dead = thread_group_leader(tsk);
|
| 98 | struct sighand_struct *sighand;
|
| 99 | struct tty_struct *tty;
|
| 100 | u64 utime, stime;
|
| 101 |
|
| 102 | sighand = rcu_dereference_check(tsk->sighand,
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| 103 | lockdep_tasklist_lock_is_held());
|
| 104 | spin_lock(&sighand->siglock);
|
| 105 |
|
| 106 | #ifdef CONFIG_POSIX_TIMERS
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| 107 | posix_cpu_timers_exit(tsk);
|
| 108 | if (group_dead)
|
| 109 | posix_cpu_timers_exit_group(tsk);
|
| 110 | #endif
|
| 111 |
|
| 112 | if (group_dead) {
|
| 113 | tty = sig->tty;
|
| 114 | sig->tty = NULL;
|
| 115 | } else {
|
| 116 | |
| 117 | * If there is any task waiting for the group exit
|
| 118 | * then notify it:
|
| 119 |
|
| 120 | if (sig->notify_count > 0 && !--sig->notify_count)
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| 121 | wake_up_process(sig->group_exec_task);
|
| 122 |
|
| 123 | if (tsk == sig->curr_target)
|
| 124 | sig->curr_target = next_thread(tsk);
|
| 125 | }
|
| 126 |
|
| 127 | add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
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| 128 | sizeof(unsigned long long));
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| 129 |
|
| 130 | |
| 131 | * Accumulate here the counters for all threads as they die. We could
|
| 132 | * skip the group leader because it is the last user of signal_struct,
|
| 133 | * but we want to avoid the race with thread_group_cputime() which can
|
| 134 | * see the empty ->thread_head list.
|
| 135 |
|
| 136 | task_cputime(tsk, &utime, &stime);
|
| 137 | write_seqlock(&sig->stats_lock);
|
| 138 | sig->utime += utime;
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| 139 | sig->stime += stime;
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| 140 | sig->gtime += task_gtime(tsk);
|
| 141 | sig->min_flt += tsk->min_flt;
|
| 142 | sig->maj_flt += tsk->maj_flt;
|
| 143 | sig->nvcsw += tsk->nvcsw;
|
| 144 | sig->nivcsw += tsk->nivcsw;
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| 145 | sig->inblock += task_io_get_inblock(tsk);
|
| 146 | sig->oublock += task_io_get_oublock(tsk);
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| 147 | task_io_accounting_add(&sig->ioac, &tsk->ioac);
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| 148 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
|
| 149 | sig->nr_threads--;
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| 150 | __unhash_process(tsk, group_dead);
|
| 151 | write_sequnlock(&sig->stats_lock);
|
| 152 |
|
| 153 | |
| 154 | * Do this under ->siglock, we can race with another thread
|
| 155 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
|
| 156 |
|
| 157 | flush_sigqueue(&tsk->pending);
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| 158 | tsk->sighand = NULL;
|
| 159 | spin_unlock(&sighand->siglock);
|
| 160 |
|
| 161 | __cleanup_sighand(sighand);
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| 162 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
|
| 163 | if (group_dead) {
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| 164 | flush_sigqueue(&sig->shared_pending);
|
| 165 | tty_kref_put(tty);
|
| 166 | }
|
| 167 | }
|
| 168 |
|
| 169 | static void delayed_put_task_struct(struct rcu_head *rhp)
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| 170 | {
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| 171 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
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| 172 |
|
| 173 | kprobe_flush_task(tsk);
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| 174 | rethook_flush_task(tsk);
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| 175 | perf_event_delayed_put(tsk);
|
| 176 | trace_sched_process_free(tsk);
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| 177 | put_task_struct(tsk);
|
| 178 | }
|
| 179 |
|
| 180 | void put_task_struct_rcu_user(struct task_struct *task)
|
| 181 | {
|
| 182 | if (refcount_dec_and_test(&task->rcu_users))
|
| 183 | call_rcu(&task->rcu, delayed_put_task_struct);
|
| 184 | }
|
| 185 |
|
| 186 | void release_task(struct task_struct *p)
|
| 187 | {
|
| 188 | struct task_struct *leader;
|
| 189 | struct pid *thread_pid;
|
| 190 | int zap_leader;
|
| 191 | repeat:
|
| 192 | |
| 193 | * can't be modifying its own credentials. But shut RCU-lockdep up
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| 194 | rcu_read_lock();
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| 195 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
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| 196 | rcu_read_unlock();
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| 197 |
|
| 198 | cgroup_release(p);
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| 199 |
|
| 200 | write_lock_irq(&tasklist_lock);
|
| 201 | ptrace_release_task(p);
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| 202 | thread_pid = get_pid(p->thread_pid);
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| 203 | __exit_signal(p);
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| 204 |
|
| 205 | |
| 206 | * If we are the last non-leader member of the thread
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| 207 | * group, and the leader is zombie, then notify the
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| 208 | * group leader's parent process. (if it wants notification.)
|
| 209 |
|
| 210 | zap_leader = 0;
|
| 211 | leader = p->group_leader;
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| 212 | if (leader != p && thread_group_empty(leader)
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| 213 | && leader->exit_state == EXIT_ZOMBIE) {
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| 214 | |
| 215 | * If we were the last child thread and the leader has
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| 216 | * exited already, and the leader's parent ignores SIGCHLD,
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| 217 | * then we are the one who should release the leader.
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| 218 |
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| 219 | zap_leader = do_notify_parent(leader, leader->exit_signal);
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| 220 | if (zap_leader)
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| 221 | leader->exit_state = EXIT_DEAD;
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| 222 | }
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| 223 |
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| 224 | write_unlock_irq(&tasklist_lock);
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| 225 | seccomp_filter_release(p);
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| 226 | proc_flush_pid(thread_pid);
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| 227 | put_pid(thread_pid);
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| 228 | release_thread(p);
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| 229 | put_task_struct_rcu_user(p);
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| 230 |
|
| 231 | p = leader;
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| 232 | if (unlikely(zap_leader))
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| 233 | goto repeat;
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| 234 | }
|
| 235 |
|
| 236 | int rcuwait_wake_up(struct rcuwait *w)
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| 237 | {
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| 238 | int ret = 0;
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| 239 | struct task_struct *task;
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| 240 |
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| 241 | rcu_read_lock();
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| 242 |
|
| 243 | |
| 244 | * Order condition vs @task, such that everything prior to the load
|
| 245 | * of @task is visible. This is the condition as to why the user called
|
| 246 | * rcuwait_wake() in the first place. Pairs with set_current_state()
|
| 247 | * barrier (A) in rcuwait_wait_event().
|
| 248 | *
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| 249 | * WAIT WAKE
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| 250 | * [S] tsk = current [S] cond = true
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| 251 | * MB (A) MB (B)
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| 252 | * [L] cond [L] tsk
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| 253 |
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| 254 | smp_mb();
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| 255 |
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| 256 | task = rcu_dereference(w->task);
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| 257 | if (task)
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| 258 | ret = wake_up_process(task);
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| 259 | rcu_read_unlock();
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| 260 |
|
| 261 | return ret;
|
| 262 | }
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| 263 | EXPORT_SYMBOL_GPL(rcuwait_wake_up);
|
| 264 |
|
| 265 | |
| 266 | * Determine if a process group is "orphaned", according to the POSIX
|
| 267 | * definition in 2.2.2.52. Orphaned process groups are not to be affected
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| 268 | * by terminal-generated stop signals. Newly orphaned process groups are
|
| 269 | * to receive a SIGHUP and a SIGCONT.
|
| 270 | *
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| 271 | * "I ask you, have you ever known what it is to be an orphan?"
|
| 272 |
|
| 273 | static int will_become_orphaned_pgrp(struct pid *pgrp,
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| 274 | struct task_struct *ignored_task)
|
| 275 | {
|
| 276 | struct task_struct *p;
|
| 277 |
|
| 278 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
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| 279 | if ((p == ignored_task) ||
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| 280 | (p->exit_state && thread_group_empty(p)) ||
|
| 281 | is_global_init(p->real_parent))
|
| 282 | continue;
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| 283 |
|
| 284 | if (task_pgrp(p->real_parent) != pgrp &&
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| 285 | task_session(p->real_parent) == task_session(p))
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| 286 | return 0;
|
| 287 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 288 |
|
| 289 | return 1;
|
| 290 | }
|
| 291 |
|
| 292 | int is_current_pgrp_orphaned(void)
|
| 293 | {
|
| 294 | int retval;
|
| 295 |
|
| 296 | read_lock(&tasklist_lock);
|
| 297 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
|
| 298 | read_unlock(&tasklist_lock);
|
| 299 |
|
| 300 | return retval;
|
| 301 | }
|
| 302 |
|
| 303 | static bool has_stopped_jobs(struct pid *pgrp)
|
| 304 | {
|
| 305 | struct task_struct *p;
|
| 306 |
|
| 307 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
|
| 308 | if (p->signal->flags & SIGNAL_STOP_STOPPED)
|
| 309 | return true;
|
| 310 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 311 |
|
| 312 | return false;
|
| 313 | }
|
| 314 |
|
| 315 | |
| 316 | * Check to see if any process groups have become orphaned as
|
| 317 | * a result of our exiting, and if they have any stopped jobs,
|
| 318 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 319 |
|
| 320 | static void
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| 321 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
|
| 322 | {
|
| 323 | struct pid *pgrp = task_pgrp(tsk);
|
| 324 | struct task_struct *ignored_task = tsk;
|
| 325 |
|
| 326 | if (!parent)
|
| 327 | |
| 328 | * we are and we were the only connection outside.
|
| 329 |
|
| 330 | parent = tsk->real_parent;
|
| 331 | else
|
| 332 | |
| 333 | * we are, and it was the only connection outside.
|
| 334 |
|
| 335 | ignored_task = NULL;
|
| 336 |
|
| 337 | if (task_pgrp(parent) != pgrp &&
|
| 338 | task_session(parent) == task_session(tsk) &&
|
| 339 | will_become_orphaned_pgrp(pgrp, ignored_task) &&
|
| 340 | has_stopped_jobs(pgrp)) {
|
| 341 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
|
| 342 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
|
| 343 | }
|
| 344 | }
|
| 345 |
|
| 346 | static void coredump_task_exit(struct task_struct *tsk)
|
| 347 | {
|
| 348 | struct core_state *core_state;
|
| 349 |
|
| 350 | |
| 351 | * Serialize with any possible pending coredump.
|
| 352 | * We must hold siglock around checking core_state
|
| 353 | * and setting PF_POSTCOREDUMP. The core-inducing thread
|
| 354 | * will increment ->nr_threads for each thread in the
|
| 355 | * group without PF_POSTCOREDUMP set.
|
| 356 |
|
| 357 | spin_lock_irq(&tsk->sighand->siglock);
|
| 358 | tsk->flags |= PF_POSTCOREDUMP;
|
| 359 | core_state = tsk->signal->core_state;
|
| 360 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 361 | if (core_state) {
|
| 362 | struct core_thread self;
|
| 363 |
|
| 364 | self.task = current;
|
| 365 | if (self.task->flags & PF_SIGNALED)
|
| 366 | self.next = xchg(&core_state->dumper.next, &self);
|
| 367 | else
|
| 368 | self.task = NULL;
|
| 369 | |
| 370 | * Implies mb(), the result of xchg() must be visible
|
| 371 | * to core_state->dumper.
|
| 372 |
|
| 373 | if (atomic_dec_and_test(&core_state->nr_threads))
|
| 374 | complete(&core_state->startup);
|
| 375 |
|
| 376 | for (;;) {
|
| 377 | set_current_state(TASK_UNINTERRUPTIBLE);
|
| 378 | if (!self.task)
|
| 379 | break;
|
| 380 | freezable_schedule();
|
| 381 | }
|
| 382 | __set_current_state(TASK_RUNNING);
|
| 383 | }
|
| 384 | }
|
| 385 |
|
| 386 | #ifdef CONFIG_MEMCG
|
| 387 | |
| 388 | * A task is exiting. If it owned this mm, find a new owner for the mm.
|
| 389 |
|
| 390 | void mm_update_next_owner(struct mm_struct *mm)
|
| 391 | {
|
| 392 | struct task_struct *c, *g, *p = current;
|
| 393 |
|
| 394 | retry:
|
| 395 | |
| 396 | * If the exiting or execing task is not the owner, it's
|
| 397 | * someone else's problem.
|
| 398 |
|
| 399 | if (mm->owner != p)
|
| 400 | return;
|
| 401 | |
| 402 | * The current owner is exiting/execing and there are no other
|
| 403 | * candidates. Do not leave the mm pointing to a possibly
|
| 404 | * freed task structure.
|
| 405 |
|
| 406 | if (atomic_read(&mm->mm_users) <= 1) {
|
| 407 | WRITE_ONCE(mm->owner, NULL);
|
| 408 | return;
|
| 409 | }
|
| 410 |
|
| 411 | read_lock(&tasklist_lock);
|
| 412 | |
| 413 | * Search in the children
|
| 414 |
|
| 415 | list_for_each_entry(c, &p->children, sibling) {
|
| 416 | if (c->mm == mm)
|
| 417 | goto assign_new_owner;
|
| 418 | }
|
| 419 |
|
| 420 | |
| 421 | * Search in the siblings
|
| 422 |
|
| 423 | list_for_each_entry(c, &p->real_parent->children, sibling) {
|
| 424 | if (c->mm == mm)
|
| 425 | goto assign_new_owner;
|
| 426 | }
|
| 427 |
|
| 428 | |
| 429 | * Search through everything else, we should not get here often.
|
| 430 |
|
| 431 | for_each_process(g) {
|
| 432 | if (g->flags & PF_KTHREAD)
|
| 433 | continue;
|
| 434 | for_each_thread(g, c) {
|
| 435 | if (c->mm == mm)
|
| 436 | goto assign_new_owner;
|
| 437 | if (c->mm)
|
| 438 | break;
|
| 439 | }
|
| 440 | }
|
| 441 | read_unlock(&tasklist_lock);
|
| 442 | |
| 443 | * We found no owner yet mm_users > 1: this implies that we are
|
| 444 | * most likely racing with swapoff (try_to_unuse()) or /proc or
|
| 445 | * ptrace or page migration (get_task_mm()). Mark owner as NULL.
|
| 446 |
|
| 447 | WRITE_ONCE(mm->owner, NULL);
|
| 448 | return;
|
| 449 |
|
| 450 | assign_new_owner:
|
| 451 | BUG_ON(c == p);
|
| 452 | get_task_struct(c);
|
| 453 | |
| 454 | * The task_lock protects c->mm from changing.
|
| 455 | * We always want mm->owner->mm == mm
|
| 456 |
|
| 457 | task_lock(c);
|
| 458 | |
| 459 | * Delay read_unlock() till we have the task_lock()
|
| 460 | * to ensure that c does not slip away underneath us
|
| 461 |
|
| 462 | read_unlock(&tasklist_lock);
|
| 463 | if (c->mm != mm) {
|
| 464 | task_unlock(c);
|
| 465 | put_task_struct(c);
|
| 466 | goto retry;
|
| 467 | }
|
| 468 | WRITE_ONCE(mm->owner, c);
|
| 469 | task_unlock(c);
|
| 470 | put_task_struct(c);
|
| 471 | }
|
| 472 | #endif
|
| 473 |
|
| 474 | |
| 475 | * Turn us into a lazy TLB process if we
|
| 476 | * aren't already..
|
| 477 |
|
| 478 | static void exit_mm(void)
|
| 479 | {
|
| 480 | struct mm_struct *mm = current->mm;
|
| 481 |
|
| 482 | exit_mm_release(current, mm);
|
| 483 | if (!mm)
|
| 484 | return;
|
| 485 | sync_mm_rss(mm);
|
| 486 | mmap_read_lock(mm);
|
| 487 | mmgrab(mm);
|
| 488 | BUG_ON(mm != current->active_mm);
|
| 489 |
|
| 490 | task_lock(current);
|
| 491 | |
| 492 | * When a thread stops operating on an address space, the loop
|
| 493 | * in membarrier_private_expedited() may not observe that
|
| 494 | * tsk->mm, and the loop in membarrier_global_expedited() may
|
| 495 | * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
|
| 496 | * rq->membarrier_state, so those would not issue an IPI.
|
| 497 | * Membarrier requires a memory barrier after accessing
|
| 498 | * user-space memory, before clearing tsk->mm or the
|
| 499 | * rq->membarrier_state.
|
| 500 |
|
| 501 | smp_mb__after_spinlock();
|
| 502 | local_irq_disable();
|
| 503 | current->mm = NULL;
|
| 504 | membarrier_update_current_mm(NULL);
|
| 505 | enter_lazy_tlb(mm, current);
|
| 506 | local_irq_enable();
|
| 507 | task_unlock(current);
|
| 508 | mmap_read_unlock(mm);
|
| 509 | mm_update_next_owner(mm);
|
| 510 | mmput(mm);
|
| 511 | if (test_thread_flag(TIF_MEMDIE))
|
| 512 | exit_oom_victim();
|
| 513 | }
|
| 514 |
|
| 515 | static struct task_struct *find_alive_thread(struct task_struct *p)
|
| 516 | {
|
| 517 | struct task_struct *t;
|
| 518 |
|
| 519 | for_each_thread(p, t) {
|
| 520 | if (!(t->flags & PF_EXITING))
|
| 521 | return t;
|
| 522 | }
|
| 523 | return NULL;
|
| 524 | }
|
| 525 |
|
| 526 | static struct task_struct *find_child_reaper(struct task_struct *father,
|
| 527 | struct list_head *dead)
|
| 528 | __releases(&tasklist_lock)
|
| 529 | __acquires(&tasklist_lock)
|
| 530 | {
|
| 531 | struct pid_namespace *pid_ns = task_active_pid_ns(father);
|
| 532 | struct task_struct *reaper = pid_ns->child_reaper;
|
| 533 | struct task_struct *p, *n;
|
| 534 |
|
| 535 | if (likely(reaper != father))
|
| 536 | return reaper;
|
| 537 |
|
| 538 | reaper = find_alive_thread(father);
|
| 539 | if (reaper) {
|
| 540 | pid_ns->child_reaper = reaper;
|
| 541 | return reaper;
|
| 542 | }
|
| 543 |
|
| 544 | write_unlock_irq(&tasklist_lock);
|
| 545 |
|
| 546 | list_for_each_entry_safe(p, n, dead, ptrace_entry) {
|
| 547 | list_del_init(&p->ptrace_entry);
|
| 548 | release_task(p);
|
| 549 | }
|
| 550 |
|
| 551 | zap_pid_ns_processes(pid_ns);
|
| 552 | write_lock_irq(&tasklist_lock);
|
| 553 |
|
| 554 | return father;
|
| 555 | }
|
| 556 |
|
| 557 | |
| 558 | * When we die, we re-parent all our children, and try to:
|
| 559 | * 1. give them to another thread in our thread group, if such a member exists
|
| 560 | * 2. give it to the first ancestor process which prctl'd itself as a
|
| 561 | * child_subreaper for its children (like a service manager)
|
| 562 | * 3. give it to the init process (PID 1) in our pid namespace
|
| 563 |
|
| 564 | static struct task_struct *find_new_reaper(struct task_struct *father,
|
| 565 | struct task_struct *child_reaper)
|
| 566 | {
|
| 567 | struct task_struct *thread, *reaper;
|
| 568 |
|
| 569 | thread = find_alive_thread(father);
|
| 570 | if (thread)
|
| 571 | return thread;
|
| 572 |
|
| 573 | if (father->signal->has_child_subreaper) {
|
| 574 | unsigned int ns_level = task_pid(father)->level;
|
| 575 | |
| 576 | * Find the first ->is_child_subreaper ancestor in our pid_ns.
|
| 577 | * We can't check reaper != child_reaper to ensure we do not
|
| 578 | * cross the namespaces, the exiting parent could be injected
|
| 579 | * by setns() + fork().
|
| 580 | * We check pid->level, this is slightly more efficient than
|
| 581 | * task_active_pid_ns(reaper) != task_active_pid_ns(father).
|
| 582 |
|
| 583 | for (reaper = father->real_parent;
|
| 584 | task_pid(reaper)->level == ns_level;
|
| 585 | reaper = reaper->real_parent) {
|
| 586 | if (reaper == &init_task)
|
| 587 | break;
|
| 588 | if (!reaper->signal->is_child_subreaper)
|
| 589 | continue;
|
| 590 | thread = find_alive_thread(reaper);
|
| 591 | if (thread)
|
| 592 | return thread;
|
| 593 | }
|
| 594 | }
|
| 595 |
|
| 596 | return child_reaper;
|
| 597 | }
|
| 598 |
|
| 599 | |
| 600 | * Any that need to be release_task'd are put on the @dead list.
|
| 601 |
|
| 602 | static void reparent_leader(struct task_struct *father, struct task_struct *p,
|
| 603 | struct list_head *dead)
|
| 604 | {
|
| 605 | if (unlikely(p->exit_state == EXIT_DEAD))
|
| 606 | return;
|
| 607 |
|
| 608 |
|
| 609 | p->exit_signal = SIGCHLD;
|
| 610 |
|
| 611 |
|
| 612 | if (!p->ptrace &&
|
| 613 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
|
| 614 | if (do_notify_parent(p, p->exit_signal)) {
|
| 615 | p->exit_state = EXIT_DEAD;
|
| 616 | list_add(&p->ptrace_entry, dead);
|
| 617 | }
|
| 618 | }
|
| 619 |
|
| 620 | kill_orphaned_pgrp(p, father);
|
| 621 | }
|
| 622 |
|
| 623 | |
| 624 | * This does two things:
|
| 625 | *
|
| 626 | * A. Make init inherit all the child processes
|
| 627 | * B. Check to see if any process groups have become orphaned
|
| 628 | * as a result of our exiting, and if they have any stopped
|
| 629 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 630 |
|
| 631 | static void forget_original_parent(struct task_struct *father,
|
| 632 | struct list_head *dead)
|
| 633 | {
|
| 634 | struct task_struct *p, *t, *reaper;
|
| 635 |
|
| 636 | if (unlikely(!list_empty(&father->ptraced)))
|
| 637 | exit_ptrace(father, dead);
|
| 638 |
|
| 639 |
|
| 640 | reaper = find_child_reaper(father, dead);
|
| 641 | if (list_empty(&father->children))
|
| 642 | return;
|
| 643 |
|
| 644 | reaper = find_new_reaper(father, reaper);
|
| 645 | list_for_each_entry(p, &father->children, sibling) {
|
| 646 | for_each_thread(p, t) {
|
| 647 | RCU_INIT_POINTER(t->real_parent, reaper);
|
| 648 | BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
|
| 649 | if (likely(!t->ptrace))
|
| 650 | t->parent = t->real_parent;
|
| 651 | if (t->pdeath_signal)
|
| 652 | group_send_sig_info(t->pdeath_signal,
|
| 653 | SEND_SIG_NOINFO, t,
|
| 654 | PIDTYPE_TGID);
|
| 655 | }
|
| 656 | |
| 657 | * If this is a threaded reparent there is no need to
|
| 658 | * notify anyone anything has happened.
|
| 659 |
|
| 660 | if (!same_thread_group(reaper, father))
|
| 661 | reparent_leader(father, p, dead);
|
| 662 | }
|
| 663 | list_splice_tail_init(&father->children, &reaper->children);
|
| 664 | }
|
| 665 |
|
| 666 | |
| 667 | * Send signals to all our closest relatives so that they know
|
| 668 | * to properly mourn us..
|
| 669 |
|
| 670 | static void exit_notify(struct task_struct *tsk, int group_dead)
|
| 671 | {
|
| 672 | bool autoreap;
|
| 673 | struct task_struct *p, *n;
|
| 674 | LIST_HEAD(dead);
|
| 675 |
|
| 676 | write_lock_irq(&tasklist_lock);
|
| 677 | forget_original_parent(tsk, &dead);
|
| 678 |
|
| 679 | if (group_dead)
|
| 680 | kill_orphaned_pgrp(tsk->group_leader, NULL);
|
| 681 |
|
| 682 | tsk->exit_state = EXIT_ZOMBIE;
|
| 683 | if (unlikely(tsk->ptrace)) {
|
| 684 | int sig = thread_group_leader(tsk) &&
|
| 685 | thread_group_empty(tsk) &&
|
| 686 | !ptrace_reparented(tsk) ?
|
| 687 | tsk->exit_signal : SIGCHLD;
|
| 688 | autoreap = do_notify_parent(tsk, sig);
|
| 689 | } else if (thread_group_leader(tsk)) {
|
| 690 | autoreap = thread_group_empty(tsk) &&
|
| 691 | do_notify_parent(tsk, tsk->exit_signal);
|
| 692 | } else {
|
| 693 | autoreap = true;
|
| 694 | }
|
| 695 |
|
| 696 | if (autoreap) {
|
| 697 | tsk->exit_state = EXIT_DEAD;
|
| 698 | list_add(&tsk->ptrace_entry, &dead);
|
| 699 | }
|
| 700 |
|
| 701 |
|
| 702 | if (unlikely(tsk->signal->notify_count < 0))
|
| 703 | wake_up_process(tsk->signal->group_exec_task);
|
| 704 | write_unlock_irq(&tasklist_lock);
|
| 705 |
|
| 706 | list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
|
| 707 | list_del_init(&p->ptrace_entry);
|
| 708 | release_task(p);
|
| 709 | }
|
| 710 | }
|
| 711 |
|
| 712 | #ifdef CONFIG_DEBUG_STACK_USAGE
|
| 713 | static void check_stack_usage(void)
|
| 714 | {
|
| 715 | static DEFINE_SPINLOCK(low_water_lock);
|
| 716 | static int lowest_to_date = THREAD_SIZE;
|
| 717 | unsigned long free;
|
| 718 |
|
| 719 | free = stack_not_used(current);
|
| 720 |
|
| 721 | if (free >= lowest_to_date)
|
| 722 | return;
|
| 723 |
|
| 724 | spin_lock(&low_water_lock);
|
| 725 | if (free < lowest_to_date) {
|
| 726 | pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
|
| 727 | current->comm, task_pid_nr(current), free);
|
| 728 | lowest_to_date = free;
|
| 729 | }
|
| 730 | spin_unlock(&low_water_lock);
|
| 731 | }
|
| 732 | #else
|
| 733 | static inline void check_stack_usage(void) {}
|
| 734 | #endif
|
| 735 |
|
| 736 | void __noreturn do_exit(long code)
|
| 737 | {
|
| 738 | struct task_struct *tsk = current;
|
| 739 | int group_dead;
|
| 740 |
|
| 741 | WARN_ON(tsk->plug);
|
| 742 |
|
| 743 | kcov_task_exit(tsk);
|
| 744 |
|
| 745 | coredump_task_exit(tsk);
|
| 746 | ptrace_event(PTRACE_EVENT_EXIT, code);
|
| 747 |
|
| 748 | validate_creds_for_do_exit(tsk);
|
| 749 |
|
| 750 | io_uring_files_cancel();
|
| 751 | exit_signals(tsk);
|
| 752 |
|
| 753 |
|
| 754 | if (tsk->mm)
|
| 755 | sync_mm_rss(tsk->mm);
|
| 756 | acct_update_integrals(tsk);
|
| 757 | group_dead = atomic_dec_and_test(&tsk->signal->live);
|
| 758 | if (group_dead) {
|
| 759 | |
| 760 | * If the last thread of global init has exited, panic
|
| 761 | * immediately to get a useable coredump.
|
| 762 |
|
| 763 | if (unlikely(is_global_init(tsk)))
|
| 764 | panic("Attempted to kill init! exitcode=0x%08x\n",
|
| 765 | tsk->signal->group_exit_code ?: (int)code);
|
| 766 |
|
| 767 | #ifdef CONFIG_POSIX_TIMERS
|
| 768 | hrtimer_cancel(&tsk->signal->real_timer);
|
| 769 | exit_itimers(tsk->signal);
|
| 770 | #endif
|
| 771 | if (tsk->mm)
|
| 772 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
|
| 773 | }
|
| 774 | acct_collect(code, group_dead);
|
| 775 | if (group_dead)
|
| 776 | tty_audit_exit();
|
| 777 | audit_free(tsk);
|
| 778 |
|
| 779 | tsk->exit_code = code;
|
| 780 | taskstats_exit(tsk, group_dead);
|
| 781 |
|
| 782 | exit_mm();
|
| 783 |
|
| 784 | if (group_dead)
|
| 785 | acct_process();
|
| 786 | trace_sched_process_exit(tsk);
|
| 787 |
|
| 788 | exit_sem(tsk);
|
| 789 | exit_shm(tsk);
|
| 790 | exit_files(tsk);
|
| 791 | exit_fs(tsk);
|
| 792 | if (group_dead)
|
| 793 | disassociate_ctty(1);
|
| 794 | exit_task_namespaces(tsk);
|
| 795 | exit_task_work(tsk);
|
| 796 | exit_thread(tsk);
|
| 797 |
|
| 798 | |
| 799 | * Flush inherited counters to the parent - before the parent
|
| 800 | * gets woken up by child-exit notifications.
|
| 801 | *
|
| 802 | * because of cgroup mode, must be called before cgroup_exit()
|
| 803 |
|
| 804 | perf_event_exit_task(tsk);
|
| 805 |
|
| 806 | sched_autogroup_exit_task(tsk);
|
| 807 | cgroup_exit(tsk);
|
| 808 |
|
| 809 | |
| 810 | * FIXME: do that only when needed, using sched_exit tracepoint
|
| 811 |
|
| 812 | flush_ptrace_hw_breakpoint(tsk);
|
| 813 |
|
| 814 | exit_tasks_rcu_start();
|
| 815 | exit_notify(tsk, group_dead);
|
| 816 | proc_exit_connector(tsk);
|
| 817 | mpol_put_task_policy(tsk);
|
| 818 | #ifdef CONFIG_FUTEX
|
| 819 | if (unlikely(current->pi_state_cache))
|
| 820 | kfree(current->pi_state_cache);
|
| 821 | #endif
|
| 822 | |
| 823 | * Make sure we are holding no locks:
|
| 824 |
|
| 825 | debug_check_no_locks_held();
|
| 826 |
|
| 827 | if (tsk->io_context)
|
| 828 | exit_io_context(tsk);
|
| 829 |
|
| 830 | if (tsk->splice_pipe)
|
| 831 | free_pipe_info(tsk->splice_pipe);
|
| 832 |
|
| 833 | if (tsk->task_frag.page)
|
| 834 | put_page(tsk->task_frag.page);
|
| 835 |
|
| 836 | validate_creds_for_do_exit(tsk);
|
| 837 | exit_task_stack_account(tsk);
|
| 838 |
|
| 839 | check_stack_usage();
|
| 840 | preempt_disable();
|
| 841 | if (tsk->nr_dirtied)
|
| 842 | __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
|
| 843 | exit_rcu();
|
| 844 | exit_tasks_rcu_finish();
|
| 845 |
|
| 846 | lockdep_free_task(tsk);
|
| 847 | do_task_dead();
|
| 848 | }
|
| 849 |
|
| 850 | void __noreturn make_task_dead(int signr)
|
| 851 | {
|
| 852 | |
| 853 | * Take the task off the cpu after something catastrophic has
|
| 854 | * happened.
|
| 855 | *
|
| 856 | * We can get here from a kernel oops, sometimes with preemption off.
|
| 857 | * Start by checking for critical errors.
|
| 858 | * Then fix up important state like USER_DS and preemption.
|
| 859 | * Then do everything else.
|
| 860 |
|
| 861 | struct task_struct *tsk = current;
|
| 862 |
|
| 863 | if (unlikely(in_interrupt()))
|
| 864 | panic("Aiee, killing interrupt handler!");
|
| 865 | if (unlikely(!tsk->pid))
|
| 866 | panic("Attempted to kill the idle task!");
|
| 867 |
|
| 868 | if (unlikely(in_atomic())) {
|
| 869 | pr_info("note: %s[%d] exited with preempt_count %d\n",
|
| 870 | current->comm, task_pid_nr(current),
|
| 871 | preempt_count());
|
| 872 | preempt_count_set(PREEMPT_ENABLED);
|
| 873 | }
|
| 874 |
|
| 875 | |
| 876 | * We're taking recursive faults here in make_task_dead. Safest is to just
|
| 877 | * leave this task alone and wait for reboot.
|
| 878 |
|
| 879 | if (unlikely(tsk->flags & PF_EXITING)) {
|
| 880 | pr_alert("Fixing recursive fault but reboot is needed!\n");
|
| 881 | futex_exit_recursive(tsk);
|
| 882 | tsk->exit_state = EXIT_DEAD;
|
| 883 | refcount_inc(&tsk->rcu_users);
|
| 884 | do_task_dead();
|
| 885 | }
|
| 886 |
|
| 887 | do_exit(signr);
|
| 888 | }
|
| 889 |
|
| 890 | SYSCALL_DEFINE1(exit, int, error_code)
|
| 891 | {
|
| 892 | do_exit((error_code&0xff)<<8);
|
| 893 | }
|
| 894 |
|
| 895 | |
| 896 | * Take down every thread in the group. This is called by fatal signals
|
| 897 | * as well as by sys_exit_group (below).
|
| 898 |
|
| 899 | void __noreturn
|
| 900 | do_group_exit(int exit_code)
|
| 901 | {
|
| 902 | struct signal_struct *sig = current->signal;
|
| 903 |
|
| 904 | if (sig->flags & SIGNAL_GROUP_EXIT)
|
| 905 | exit_code = sig->group_exit_code;
|
| 906 | else if (sig->group_exec_task)
|
| 907 | exit_code = 0;
|
| 908 | else if (!thread_group_empty(current)) {
|
| 909 | struct sighand_struct *const sighand = current->sighand;
|
| 910 |
|
| 911 | spin_lock_irq(&sighand->siglock);
|
| 912 | if (sig->flags & SIGNAL_GROUP_EXIT)
|
| 913 |
|
| 914 | exit_code = sig->group_exit_code;
|
| 915 | else if (sig->group_exec_task)
|
| 916 | exit_code = 0;
|
| 917 | else {
|
| 918 | sig->group_exit_code = exit_code;
|
| 919 | sig->flags = SIGNAL_GROUP_EXIT;
|
| 920 | zap_other_threads(current);
|
| 921 | }
|
| 922 | spin_unlock_irq(&sighand->siglock);
|
| 923 | }
|
| 924 |
|
| 925 | do_exit(exit_code);
|
| 926 |
|
| 927 | }
|
| 928 |
|
| 929 | |
| 930 | * this kills every thread in the thread group. Note that any externally
|
| 931 | * wait4()-ing process will get the correct exit code - even if this
|
| 932 | * thread is not the thread group leader.
|
| 933 |
|
| 934 | SYSCALL_DEFINE1(exit_group, int, error_code)
|
| 935 | {
|
| 936 | do_group_exit((error_code & 0xff) << 8);
|
| 937 |
|
| 938 | return 0;
|
| 939 | }
|
| 940 |
|
| 941 | struct waitid_info {
|
| 942 | pid_t pid;
|
| 943 | uid_t uid;
|
| 944 | int status;
|
| 945 | int cause;
|
| 946 | };
|
| 947 |
|
| 948 | struct wait_opts {
|
| 949 | enum pid_type wo_type;
|
| 950 | int wo_flags;
|
| 951 | struct pid *wo_pid;
|
| 952 |
|
| 953 | struct waitid_info *wo_info;
|
| 954 | int wo_stat;
|
| 955 | struct rusage *wo_rusage;
|
| 956 |
|
| 957 | wait_queue_entry_t child_wait;
|
| 958 | int notask_error;
|
| 959 | };
|
| 960 |
|
| 961 | static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
|
| 962 | {
|
| 963 | return wo->wo_type == PIDTYPE_MAX ||
|
| 964 | task_pid_type(p, wo->wo_type) == wo->wo_pid;
|
| 965 | }
|
| 966 |
|
| 967 | static int
|
| 968 | eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p)
|
| 969 | {
|
| 970 | if (!eligible_pid(wo, p))
|
| 971 | return 0;
|
| 972 |
|
| 973 | |
| 974 | * Wait for all children (clone and not) if __WALL is set or
|
| 975 | * if it is traced by us.
|
| 976 |
|
| 977 | if (ptrace || (wo->wo_flags & __WALL))
|
| 978 | return 1;
|
| 979 |
|
| 980 | |
| 981 | * Otherwise, wait for clone children *only* if __WCLONE is set;
|
| 982 | * otherwise, wait for non-clone children *only*.
|
| 983 | *
|
| 984 | * Note: a "clone" child here is one that reports to its parent
|
| 985 | * using a signal other than SIGCHLD, or a non-leader thread which
|
| 986 | * we can only see if it is traced by us.
|
| 987 |
|
| 988 | if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
|
| 989 | return 0;
|
| 990 |
|
| 991 | return 1;
|
| 992 | }
|
| 993 |
|
| 994 | |
| 995 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
|
| 996 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 997 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 998 | * released the lock and the system call should return.
|
| 999 |
|
| 1000 | static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
|
| 1001 | {
|
| 1002 | int state, status;
|
| 1003 | pid_t pid = task_pid_vnr(p);
|
| 1004 | uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1005 | struct waitid_info *infop;
|
| 1006 |
|
| 1007 | if (!likely(wo->wo_flags & WEXITED))
|
| 1008 | return 0;
|
| 1009 |
|
| 1010 | if (unlikely(wo->wo_flags & WNOWAIT)) {
|
| 1011 | status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
| 1012 | ? p->signal->group_exit_code : p->exit_code;
|
| 1013 | get_task_struct(p);
|
| 1014 | read_unlock(&tasklist_lock);
|
| 1015 | sched_annotate_sleep();
|
| 1016 | if (wo->wo_rusage)
|
| 1017 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1018 | put_task_struct(p);
|
| 1019 | goto out_info;
|
| 1020 | }
|
| 1021 | |
| 1022 | * Move the task's state to DEAD/TRACE, only one thread can do this.
|
| 1023 |
|
| 1024 | state = (ptrace_reparented(p) && thread_group_leader(p)) ?
|
| 1025 | EXIT_TRACE : EXIT_DEAD;
|
| 1026 | if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
|
| 1027 | return 0;
|
| 1028 | |
| 1029 | * We own this thread, nobody else can reap it.
|
| 1030 |
|
| 1031 | read_unlock(&tasklist_lock);
|
| 1032 | sched_annotate_sleep();
|
| 1033 |
|
| 1034 | |
| 1035 | * Check thread_group_leader() to exclude the traced sub-threads.
|
| 1036 |
|
| 1037 | if (state == EXIT_DEAD && thread_group_leader(p)) {
|
| 1038 | struct signal_struct *sig = p->signal;
|
| 1039 | struct signal_struct *psig = current->signal;
|
| 1040 | unsigned long maxrss;
|
| 1041 | u64 tgutime, tgstime;
|
| 1042 |
|
| 1043 | |
| 1044 | * The resource counters for the group leader are in its
|
| 1045 | * own task_struct. Those for dead threads in the group
|
| 1046 | * are in its signal_struct, as are those for the child
|
| 1047 | * processes it has previously reaped. All these
|
| 1048 | * accumulate in the parent's signal_struct c* fields.
|
| 1049 | *
|
| 1050 | * We don't bother to take a lock here to protect these
|
| 1051 | * p->signal fields because the whole thread group is dead
|
| 1052 | * and nobody can change them.
|
| 1053 | *
|
| 1054 | * psig->stats_lock also protects us from our sub-theads
|
| 1055 | * which can reap other children at the same time. Until
|
| 1056 | * we change k_getrusage()-like users to rely on this lock
|
| 1057 | * we have to take ->siglock as well.
|
| 1058 | *
|
| 1059 | * We use thread_group_cputime_adjusted() to get times for
|
| 1060 | * the thread group, which consolidates times for all threads
|
| 1061 | * in the group including the group leader.
|
| 1062 |
|
| 1063 | thread_group_cputime_adjusted(p, &tgutime, &tgstime);
|
| 1064 | spin_lock_irq(¤t->sighand->siglock);
|
| 1065 | write_seqlock(&psig->stats_lock);
|
| 1066 | psig->cutime += tgutime + sig->cutime;
|
| 1067 | psig->cstime += tgstime + sig->cstime;
|
| 1068 | psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
|
| 1069 | psig->cmin_flt +=
|
| 1070 | p->min_flt + sig->min_flt + sig->cmin_flt;
|
| 1071 | psig->cmaj_flt +=
|
| 1072 | p->maj_flt + sig->maj_flt + sig->cmaj_flt;
|
| 1073 | psig->cnvcsw +=
|
| 1074 | p->nvcsw + sig->nvcsw + sig->cnvcsw;
|
| 1075 | psig->cnivcsw +=
|
| 1076 | p->nivcsw + sig->nivcsw + sig->cnivcsw;
|
| 1077 | psig->cinblock +=
|
| 1078 | task_io_get_inblock(p) +
|
| 1079 | sig->inblock + sig->cinblock;
|
| 1080 | psig->coublock +=
|
| 1081 | task_io_get_oublock(p) +
|
| 1082 | sig->oublock + sig->coublock;
|
| 1083 | maxrss = max(sig->maxrss, sig->cmaxrss);
|
| 1084 | if (psig->cmaxrss < maxrss)
|
| 1085 | psig->cmaxrss = maxrss;
|
| 1086 | task_io_accounting_add(&psig->ioac, &p->ioac);
|
| 1087 | task_io_accounting_add(&psig->ioac, &sig->ioac);
|
| 1088 | write_sequnlock(&psig->stats_lock);
|
| 1089 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1090 | }
|
| 1091 |
|
| 1092 | if (wo->wo_rusage)
|
| 1093 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1094 | status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
| 1095 | ? p->signal->group_exit_code : p->exit_code;
|
| 1096 | wo->wo_stat = status;
|
| 1097 |
|
| 1098 | if (state == EXIT_TRACE) {
|
| 1099 | write_lock_irq(&tasklist_lock);
|
| 1100 |
|
| 1101 | ptrace_unlink(p);
|
| 1102 |
|
| 1103 |
|
| 1104 | state = EXIT_ZOMBIE;
|
| 1105 | if (do_notify_parent(p, p->exit_signal))
|
| 1106 | state = EXIT_DEAD;
|
| 1107 | p->exit_state = state;
|
| 1108 | write_unlock_irq(&tasklist_lock);
|
| 1109 | }
|
| 1110 | if (state == EXIT_DEAD)
|
| 1111 | release_task(p);
|
| 1112 |
|
| 1113 | out_info:
|
| 1114 | infop = wo->wo_info;
|
| 1115 | if (infop) {
|
| 1116 | if ((status & 0x7f) == 0) {
|
| 1117 | infop->cause = CLD_EXITED;
|
| 1118 | infop->status = status >> 8;
|
| 1119 | } else {
|
| 1120 | infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
| 1121 | infop->status = status & 0x7f;
|
| 1122 | }
|
| 1123 | infop->pid = pid;
|
| 1124 | infop->uid = uid;
|
| 1125 | }
|
| 1126 |
|
| 1127 | return pid;
|
| 1128 | }
|
| 1129 |
|
| 1130 | static int *task_stopped_code(struct task_struct *p, bool ptrace)
|
| 1131 | {
|
| 1132 | if (ptrace) {
|
| 1133 | if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING))
|
| 1134 | return &p->exit_code;
|
| 1135 | } else {
|
| 1136 | if (p->signal->flags & SIGNAL_STOP_STOPPED)
|
| 1137 | return &p->signal->group_exit_code;
|
| 1138 | }
|
| 1139 | return NULL;
|
| 1140 | }
|
| 1141 |
|
| 1142 | |
| 1143 | * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
|
| 1144 | * @wo: wait options
|
| 1145 | * @ptrace: is the wait for ptrace
|
| 1146 | * @p: task to wait for
|
| 1147 | *
|
| 1148 | * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
|
| 1149 | *
|
| 1150 | * CONTEXT:
|
| 1151 | * read_lock(&tasklist_lock), which is released if return value is
|
| 1152 | * non-zero. Also, grabs and releases @p->sighand->siglock.
|
| 1153 | *
|
| 1154 | * RETURNS:
|
| 1155 | * 0 if wait condition didn't exist and search for other wait conditions
|
| 1156 | * should continue. Non-zero return, -errno on failure and @p's pid on
|
| 1157 | * success, implies that tasklist_lock is released and wait condition
|
| 1158 | * search should terminate.
|
| 1159 |
|
| 1160 | static int wait_task_stopped(struct wait_opts *wo,
|
| 1161 | int ptrace, struct task_struct *p)
|
| 1162 | {
|
| 1163 | struct waitid_info *infop;
|
| 1164 | int exit_code, *p_code, why;
|
| 1165 | uid_t uid = 0;
|
| 1166 | pid_t pid;
|
| 1167 |
|
| 1168 | |
| 1169 | * Traditionally we see ptrace'd stopped tasks regardless of options.
|
| 1170 |
|
| 1171 | if (!ptrace && !(wo->wo_flags & WUNTRACED))
|
| 1172 | return 0;
|
| 1173 |
|
| 1174 | if (!task_stopped_code(p, ptrace))
|
| 1175 | return 0;
|
| 1176 |
|
| 1177 | exit_code = 0;
|
| 1178 | spin_lock_irq(&p->sighand->siglock);
|
| 1179 |
|
| 1180 | p_code = task_stopped_code(p, ptrace);
|
| 1181 | if (unlikely(!p_code))
|
| 1182 | goto unlock_sig;
|
| 1183 |
|
| 1184 | exit_code = *p_code;
|
| 1185 | if (!exit_code)
|
| 1186 | goto unlock_sig;
|
| 1187 |
|
| 1188 | if (!unlikely(wo->wo_flags & WNOWAIT))
|
| 1189 | *p_code = 0;
|
| 1190 |
|
| 1191 | uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1192 | unlock_sig:
|
| 1193 | spin_unlock_irq(&p->sighand->siglock);
|
| 1194 | if (!exit_code)
|
| 1195 | return 0;
|
| 1196 |
|
| 1197 | |
| 1198 | * Now we are pretty sure this task is interesting.
|
| 1199 | * Make sure it doesn't get reaped out from under us while we
|
| 1200 | * give up the lock and then examine it below. We don't want to
|
| 1201 | * keep holding onto the tasklist_lock while we call getrusage and
|
| 1202 | * possibly take page faults for user memory.
|
| 1203 |
|
| 1204 | get_task_struct(p);
|
| 1205 | pid = task_pid_vnr(p);
|
| 1206 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
|
| 1207 | read_unlock(&tasklist_lock);
|
| 1208 | sched_annotate_sleep();
|
| 1209 | if (wo->wo_rusage)
|
| 1210 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1211 | put_task_struct(p);
|
| 1212 |
|
| 1213 | if (likely(!(wo->wo_flags & WNOWAIT)))
|
| 1214 | wo->wo_stat = (exit_code << 8) | 0x7f;
|
| 1215 |
|
| 1216 | infop = wo->wo_info;
|
| 1217 | if (infop) {
|
| 1218 | infop->cause = why;
|
| 1219 | infop->status = exit_code;
|
| 1220 | infop->pid = pid;
|
| 1221 | infop->uid = uid;
|
| 1222 | }
|
| 1223 | return pid;
|
| 1224 | }
|
| 1225 |
|
| 1226 | |
| 1227 | * Handle do_wait work for one task in a live, non-stopped state.
|
| 1228 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1229 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1230 | * released the lock and the system call should return.
|
| 1231 |
|
| 1232 | static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
|
| 1233 | {
|
| 1234 | struct waitid_info *infop;
|
| 1235 | pid_t pid;
|
| 1236 | uid_t uid;
|
| 1237 |
|
| 1238 | if (!unlikely(wo->wo_flags & WCONTINUED))
|
| 1239 | return 0;
|
| 1240 |
|
| 1241 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
|
| 1242 | return 0;
|
| 1243 |
|
| 1244 | spin_lock_irq(&p->sighand->siglock);
|
| 1245 |
|
| 1246 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
|
| 1247 | spin_unlock_irq(&p->sighand->siglock);
|
| 1248 | return 0;
|
| 1249 | }
|
| 1250 | if (!unlikely(wo->wo_flags & WNOWAIT))
|
| 1251 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
|
| 1252 | uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1253 | spin_unlock_irq(&p->sighand->siglock);
|
| 1254 |
|
| 1255 | pid = task_pid_vnr(p);
|
| 1256 | get_task_struct(p);
|
| 1257 | read_unlock(&tasklist_lock);
|
| 1258 | sched_annotate_sleep();
|
| 1259 | if (wo->wo_rusage)
|
| 1260 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1261 | put_task_struct(p);
|
| 1262 |
|
| 1263 | infop = wo->wo_info;
|
| 1264 | if (!infop) {
|
| 1265 | wo->wo_stat = 0xffff;
|
| 1266 | } else {
|
| 1267 | infop->cause = CLD_CONTINUED;
|
| 1268 | infop->pid = pid;
|
| 1269 | infop->uid = uid;
|
| 1270 | infop->status = SIGCONT;
|
| 1271 | }
|
| 1272 | return pid;
|
| 1273 | }
|
| 1274 |
|
| 1275 | |
| 1276 | * Consider @p for a wait by @parent.
|
| 1277 | *
|
| 1278 | * -ECHILD should be in ->notask_error before the first call.
|
| 1279 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1280 | * Returns zero if the search for a child should continue;
|
| 1281 | * then ->notask_error is 0 if @p is an eligible child,
|
| 1282 | * or still -ECHILD.
|
| 1283 |
|
| 1284 | static int wait_consider_task(struct wait_opts *wo, int ptrace,
|
| 1285 | struct task_struct *p)
|
| 1286 | {
|
| 1287 | |
| 1288 | * We can race with wait_task_zombie() from another thread.
|
| 1289 | * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
|
| 1290 | * can't confuse the checks below.
|
| 1291 |
|
| 1292 | int exit_state = READ_ONCE(p->exit_state);
|
| 1293 | int ret;
|
| 1294 |
|
| 1295 | if (unlikely(exit_state == EXIT_DEAD))
|
| 1296 | return 0;
|
| 1297 |
|
| 1298 | ret = eligible_child(wo, ptrace, p);
|
| 1299 | if (!ret)
|
| 1300 | return ret;
|
| 1301 |
|
| 1302 | if (unlikely(exit_state == EXIT_TRACE)) {
|
| 1303 | |
| 1304 | * ptrace == 0 means we are the natural parent. In this case
|
| 1305 | * we should clear notask_error, debugger will notify us.
|
| 1306 |
|
| 1307 | if (likely(!ptrace))
|
| 1308 | wo->notask_error = 0;
|
| 1309 | return 0;
|
| 1310 | }
|
| 1311 |
|
| 1312 | if (likely(!ptrace) && unlikely(p->ptrace)) {
|
| 1313 | |
| 1314 | * If it is traced by its real parent's group, just pretend
|
| 1315 | * the caller is ptrace_do_wait() and reap this child if it
|
| 1316 | * is zombie.
|
| 1317 | *
|
| 1318 | * This also hides group stop state from real parent; otherwise
|
| 1319 | * a single stop can be reported twice as group and ptrace stop.
|
| 1320 | * If a ptracer wants to distinguish these two events for its
|
| 1321 | * own children it should create a separate process which takes
|
| 1322 | * the role of real parent.
|
| 1323 |
|
| 1324 | if (!ptrace_reparented(p))
|
| 1325 | ptrace = 1;
|
| 1326 | }
|
| 1327 |
|
| 1328 |
|
| 1329 | if (exit_state == EXIT_ZOMBIE) {
|
| 1330 |
|
| 1331 | if (!delay_group_leader(p)) {
|
| 1332 | |
| 1333 | * A zombie ptracee is only visible to its ptracer.
|
| 1334 | * Notification and reaping will be cascaded to the
|
| 1335 | * real parent when the ptracer detaches.
|
| 1336 |
|
| 1337 | if (unlikely(ptrace) || likely(!p->ptrace))
|
| 1338 | return wait_task_zombie(wo, p);
|
| 1339 | }
|
| 1340 |
|
| 1341 | |
| 1342 | * Allow access to stopped/continued state via zombie by
|
| 1343 | * falling through. Clearing of notask_error is complex.
|
| 1344 | *
|
| 1345 | * When !@ptrace:
|
| 1346 | *
|
| 1347 | * If WEXITED is set, notask_error should naturally be
|
| 1348 | * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
|
| 1349 | * so, if there are live subthreads, there are events to
|
| 1350 | * wait for. If all subthreads are dead, it's still safe
|
| 1351 | * to clear - this function will be called again in finite
|
| 1352 | * amount time once all the subthreads are released and
|
| 1353 | * will then return without clearing.
|
| 1354 | *
|
| 1355 | * When @ptrace:
|
| 1356 | *
|
| 1357 | * Stopped state is per-task and thus can't change once the
|
| 1358 | * target task dies. Only continued and exited can happen.
|
| 1359 | * Clear notask_error if WCONTINUED | WEXITED.
|
| 1360 |
|
| 1361 | if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
|
| 1362 | wo->notask_error = 0;
|
| 1363 | } else {
|
| 1364 | |
| 1365 | * @p is alive and it's gonna stop, continue or exit, so
|
| 1366 | * there always is something to wait for.
|
| 1367 |
|
| 1368 | wo->notask_error = 0;
|
| 1369 | }
|
| 1370 |
|
| 1371 | |
| 1372 | * Wait for stopped. Depending on @ptrace, different stopped state
|
| 1373 | * is used and the two don't interact with each other.
|
| 1374 |
|
| 1375 | ret = wait_task_stopped(wo, ptrace, p);
|
| 1376 | if (ret)
|
| 1377 | return ret;
|
| 1378 |
|
| 1379 | |
| 1380 | * Wait for continued. There's only one continued state and the
|
| 1381 | * ptracer can consume it which can confuse the real parent. Don't
|
| 1382 | * use WCONTINUED from ptracer. You don't need or want it.
|
| 1383 |
|
| 1384 | return wait_task_continued(wo, p);
|
| 1385 | }
|
| 1386 |
|
| 1387 | |
| 1388 | * Do the work of do_wait() for one thread in the group, @tsk.
|
| 1389 | *
|
| 1390 | * -ECHILD should be in ->notask_error before the first call.
|
| 1391 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1392 | * Returns zero if the search for a child should continue; then
|
| 1393 | * ->notask_error is 0 if there were any eligible children,
|
| 1394 | * or still -ECHILD.
|
| 1395 |
|
| 1396 | static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
|
| 1397 | {
|
| 1398 | struct task_struct *p;
|
| 1399 |
|
| 1400 | list_for_each_entry(p, &tsk->children, sibling) {
|
| 1401 | int ret = wait_consider_task(wo, 0, p);
|
| 1402 |
|
| 1403 | if (ret)
|
| 1404 | return ret;
|
| 1405 | }
|
| 1406 |
|
| 1407 | return 0;
|
| 1408 | }
|
| 1409 |
|
| 1410 | static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
|
| 1411 | {
|
| 1412 | struct task_struct *p;
|
| 1413 |
|
| 1414 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
|
| 1415 | int ret = wait_consider_task(wo, 1, p);
|
| 1416 |
|
| 1417 | if (ret)
|
| 1418 | return ret;
|
| 1419 | }
|
| 1420 |
|
| 1421 | return 0;
|
| 1422 | }
|
| 1423 |
|
| 1424 | static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
|
| 1425 | int sync, void *key)
|
| 1426 | {
|
| 1427 | struct wait_opts *wo = container_of(wait, struct wait_opts,
|
| 1428 | child_wait);
|
| 1429 | struct task_struct *p = key;
|
| 1430 |
|
| 1431 | if (!eligible_pid(wo, p))
|
| 1432 | return 0;
|
| 1433 |
|
| 1434 | if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
|
| 1435 | return 0;
|
| 1436 |
|
| 1437 | return default_wake_function(wait, mode, sync, key);
|
| 1438 | }
|
| 1439 |
|
| 1440 | void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
|
| 1441 | {
|
| 1442 | __wake_up_sync_key(&parent->signal->wait_chldexit,
|
| 1443 | TASK_INTERRUPTIBLE, p);
|
| 1444 | }
|
| 1445 |
|
| 1446 | static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
|
| 1447 | struct task_struct *target)
|
| 1448 | {
|
| 1449 | struct task_struct *parent =
|
| 1450 | !ptrace ? target->real_parent : target->parent;
|
| 1451 |
|
| 1452 | return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
|
| 1453 | same_thread_group(current, parent));
|
| 1454 | }
|
| 1455 |
|
| 1456 | |
| 1457 | * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
|
| 1458 | * and tracee lists to find the target task.
|
| 1459 |
|
| 1460 | static int do_wait_pid(struct wait_opts *wo)
|
| 1461 | {
|
| 1462 | bool ptrace;
|
| 1463 | struct task_struct *target;
|
| 1464 | int retval;
|
| 1465 |
|
| 1466 | ptrace = false;
|
| 1467 | target = pid_task(wo->wo_pid, PIDTYPE_TGID);
|
| 1468 | if (target && is_effectively_child(wo, ptrace, target)) {
|
| 1469 | retval = wait_consider_task(wo, ptrace, target);
|
| 1470 | if (retval)
|
| 1471 | return retval;
|
| 1472 | }
|
| 1473 |
|
| 1474 | ptrace = true;
|
| 1475 | target = pid_task(wo->wo_pid, PIDTYPE_PID);
|
| 1476 | if (target && target->ptrace &&
|
| 1477 | is_effectively_child(wo, ptrace, target)) {
|
| 1478 | retval = wait_consider_task(wo, ptrace, target);
|
| 1479 | if (retval)
|
| 1480 | return retval;
|
| 1481 | }
|
| 1482 |
|
| 1483 | return 0;
|
| 1484 | }
|
| 1485 |
|
| 1486 | static long do_wait(struct wait_opts *wo)
|
| 1487 | {
|
| 1488 | int retval;
|
| 1489 |
|
| 1490 | trace_sched_process_wait(wo->wo_pid);
|
| 1491 |
|
| 1492 | init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
|
| 1493 | wo->child_wait.private = current;
|
| 1494 | add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
|
| 1495 | repeat:
|
| 1496 | |
| 1497 | * If there is nothing that can match our criteria, just get out.
|
| 1498 | * We will clear ->notask_error to zero if we see any child that
|
| 1499 | * might later match our criteria, even if we are not able to reap
|
| 1500 | * it yet.
|
| 1501 |
|
| 1502 | wo->notask_error = -ECHILD;
|
| 1503 | if ((wo->wo_type < PIDTYPE_MAX) &&
|
| 1504 | (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
|
| 1505 | goto notask;
|
| 1506 |
|
| 1507 | set_current_state(TASK_INTERRUPTIBLE);
|
| 1508 | read_lock(&tasklist_lock);
|
| 1509 |
|
| 1510 | if (wo->wo_type == PIDTYPE_PID) {
|
| 1511 | retval = do_wait_pid(wo);
|
| 1512 | if (retval)
|
| 1513 | goto end;
|
| 1514 | } else {
|
| 1515 | struct task_struct *tsk = current;
|
| 1516 |
|
| 1517 | do {
|
| 1518 | retval = do_wait_thread(wo, tsk);
|
| 1519 | if (retval)
|
| 1520 | goto end;
|
| 1521 |
|
| 1522 | retval = ptrace_do_wait(wo, tsk);
|
| 1523 | if (retval)
|
| 1524 | goto end;
|
| 1525 |
|
| 1526 | if (wo->wo_flags & __WNOTHREAD)
|
| 1527 | break;
|
| 1528 | } while_each_thread(current, tsk);
|
| 1529 | }
|
| 1530 | read_unlock(&tasklist_lock);
|
| 1531 |
|
| 1532 | notask:
|
| 1533 | retval = wo->notask_error;
|
| 1534 | if (!retval && !(wo->wo_flags & WNOHANG)) {
|
| 1535 | retval = -ERESTARTSYS;
|
| 1536 | if (!signal_pending(current)) {
|
| 1537 | schedule();
|
| 1538 | goto repeat;
|
| 1539 | }
|
| 1540 | }
|
| 1541 | end:
|
| 1542 | __set_current_state(TASK_RUNNING);
|
| 1543 | remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
|
| 1544 | return retval;
|
| 1545 | }
|
| 1546 |
|
| 1547 | static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
|
| 1548 | int options, struct rusage *ru)
|
| 1549 | {
|
| 1550 | struct wait_opts wo;
|
| 1551 | struct pid *pid = NULL;
|
| 1552 | enum pid_type type;
|
| 1553 | long ret;
|
| 1554 | unsigned int f_flags = 0;
|
| 1555 |
|
| 1556 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
|
| 1557 | __WNOTHREAD|__WCLONE|__WALL))
|
| 1558 | return -EINVAL;
|
| 1559 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
|
| 1560 | return -EINVAL;
|
| 1561 |
|
| 1562 | switch (which) {
|
| 1563 | case P_ALL:
|
| 1564 | type = PIDTYPE_MAX;
|
| 1565 | break;
|
| 1566 | case P_PID:
|
| 1567 | type = PIDTYPE_PID;
|
| 1568 | if (upid <= 0)
|
| 1569 | return -EINVAL;
|
| 1570 |
|
| 1571 | pid = find_get_pid(upid);
|
| 1572 | break;
|
| 1573 | case P_PGID:
|
| 1574 | type = PIDTYPE_PGID;
|
| 1575 | if (upid < 0)
|
| 1576 | return -EINVAL;
|
| 1577 |
|
| 1578 | if (upid)
|
| 1579 | pid = find_get_pid(upid);
|
| 1580 | else
|
| 1581 | pid = get_task_pid(current, PIDTYPE_PGID);
|
| 1582 | break;
|
| 1583 | case P_PIDFD:
|
| 1584 | type = PIDTYPE_PID;
|
| 1585 | if (upid < 0)
|
| 1586 | return -EINVAL;
|
| 1587 |
|
| 1588 | pid = pidfd_get_pid(upid, &f_flags);
|
| 1589 | if (IS_ERR(pid))
|
| 1590 | return PTR_ERR(pid);
|
| 1591 |
|
| 1592 | break;
|
| 1593 | default:
|
| 1594 | return -EINVAL;
|
| 1595 | }
|
| 1596 |
|
| 1597 | wo.wo_type = type;
|
| 1598 | wo.wo_pid = pid;
|
| 1599 | wo.wo_flags = options;
|
| 1600 | wo.wo_info = infop;
|
| 1601 | wo.wo_rusage = ru;
|
| 1602 | if (f_flags & O_NONBLOCK)
|
| 1603 | wo.wo_flags |= WNOHANG;
|
| 1604 |
|
| 1605 | ret = do_wait(&wo);
|
| 1606 | if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK))
|
| 1607 | ret = -EAGAIN;
|
| 1608 |
|
| 1609 | put_pid(pid);
|
| 1610 | return ret;
|
| 1611 | }
|
| 1612 |
|
| 1613 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
|
| 1614 | infop, int, options, struct rusage __user *, ru)
|
| 1615 | {
|
| 1616 | struct rusage r;
|
| 1617 | struct waitid_info info = {.status = 0};
|
| 1618 | long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
|
| 1619 | int signo = 0;
|
| 1620 |
|
| 1621 | if (err > 0) {
|
| 1622 | signo = SIGCHLD;
|
| 1623 | err = 0;
|
| 1624 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
|
| 1625 | return -EFAULT;
|
| 1626 | }
|
| 1627 | if (!infop)
|
| 1628 | return err;
|
| 1629 |
|
| 1630 | if (!user_write_access_begin(infop, sizeof(*infop)))
|
| 1631 | return -EFAULT;
|
| 1632 |
|
| 1633 | unsafe_put_user(signo, &infop->si_signo, Efault);
|
| 1634 | unsafe_put_user(0, &infop->si_errno, Efault);
|
| 1635 | unsafe_put_user(info.cause, &infop->si_code, Efault);
|
| 1636 | unsafe_put_user(info.pid, &infop->si_pid, Efault);
|
| 1637 | unsafe_put_user(info.uid, &infop->si_uid, Efault);
|
| 1638 | unsafe_put_user(info.status, &infop->si_status, Efault);
|
| 1639 | user_write_access_end();
|
| 1640 | return err;
|
| 1641 | Efault:
|
| 1642 | user_write_access_end();
|
| 1643 | return -EFAULT;
|
| 1644 | }
|
| 1645 |
|
| 1646 | long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
|
| 1647 | struct rusage *ru)
|
| 1648 | {
|
| 1649 | struct wait_opts wo;
|
| 1650 | struct pid *pid = NULL;
|
| 1651 | enum pid_type type;
|
| 1652 | long ret;
|
| 1653 |
|
| 1654 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
|
| 1655 | __WNOTHREAD|__WCLONE|__WALL))
|
| 1656 | return -EINVAL;
|
| 1657 |
|
| 1658 |
|
| 1659 | if (upid == INT_MIN)
|
| 1660 | return -ESRCH;
|
| 1661 |
|
| 1662 | if (upid == -1)
|
| 1663 | type = PIDTYPE_MAX;
|
| 1664 | else if (upid < 0) {
|
| 1665 | type = PIDTYPE_PGID;
|
| 1666 | pid = find_get_pid(-upid);
|
| 1667 | } else if (upid == 0) {
|
| 1668 | type = PIDTYPE_PGID;
|
| 1669 | pid = get_task_pid(current, PIDTYPE_PGID);
|
| 1670 | } else {
|
| 1671 | type = PIDTYPE_PID;
|
| 1672 | pid = find_get_pid(upid);
|
| 1673 | }
|
| 1674 |
|
| 1675 | wo.wo_type = type;
|
| 1676 | wo.wo_pid = pid;
|
| 1677 | wo.wo_flags = options | WEXITED;
|
| 1678 | wo.wo_info = NULL;
|
| 1679 | wo.wo_stat = 0;
|
| 1680 | wo.wo_rusage = ru;
|
| 1681 | ret = do_wait(&wo);
|
| 1682 | put_pid(pid);
|
| 1683 | if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr))
|
| 1684 | ret = -EFAULT;
|
| 1685 |
|
| 1686 | return ret;
|
| 1687 | }
|
| 1688 |
|
| 1689 | int kernel_wait(pid_t pid, int *stat)
|
| 1690 | {
|
| 1691 | struct wait_opts wo = {
|
| 1692 | .wo_type = PIDTYPE_PID,
|
| 1693 | .wo_pid = find_get_pid(pid),
|
| 1694 | .wo_flags = WEXITED,
|
| 1695 | };
|
| 1696 | int ret;
|
| 1697 |
|
| 1698 | ret = do_wait(&wo);
|
| 1699 | if (ret > 0 && wo.wo_stat)
|
| 1700 | *stat = wo.wo_stat;
|
| 1701 | put_pid(wo.wo_pid);
|
| 1702 | return ret;
|
| 1703 | }
|
| 1704 |
|
| 1705 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
|
| 1706 | int, options, struct rusage __user *, ru)
|
| 1707 | {
|
| 1708 | struct rusage r;
|
| 1709 | long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);
|
| 1710 |
|
| 1711 | if (err > 0) {
|
| 1712 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
|
| 1713 | return -EFAULT;
|
| 1714 | }
|
| 1715 | return err;
|
| 1716 | }
|
| 1717 |
|
| 1718 | #ifdef __ARCH_WANT_SYS_WAITPID
|
| 1719 |
|
| 1720 | |
| 1721 | * sys_waitpid() remains for compatibility. waitpid() should be
|
| 1722 | * implemented by calling sys_wait4() from libc.a.
|
| 1723 |
|
| 1724 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
|
| 1725 | {
|
| 1726 | return kernel_wait4(pid, stat_addr, options, NULL);
|
| 1727 | }
|
| 1728 |
|
| 1729 | #endif
|
| 1730 |
|
| 1731 | #ifdef CONFIG_COMPAT
|
| 1732 | COMPAT_SYSCALL_DEFINE4(wait4,
|
| 1733 | compat_pid_t, pid,
|
| 1734 | compat_uint_t __user *, stat_addr,
|
| 1735 | int, options,
|
| 1736 | struct compat_rusage __user *, ru)
|
| 1737 | {
|
| 1738 | struct rusage r;
|
| 1739 | long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);
|
| 1740 | if (err > 0) {
|
| 1741 | if (ru && put_compat_rusage(&r, ru))
|
| 1742 | return -EFAULT;
|
| 1743 | }
|
| 1744 | return err;
|
| 1745 | }
|
| 1746 |
|
| 1747 | COMPAT_SYSCALL_DEFINE5(waitid,
|
| 1748 | int, which, compat_pid_t, pid,
|
| 1749 | struct compat_siginfo __user *, infop, int, options,
|
| 1750 | struct compat_rusage __user *, uru)
|
| 1751 | {
|
| 1752 | struct rusage ru;
|
| 1753 | struct waitid_info info = {.status = 0};
|
| 1754 | long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);
|
| 1755 | int signo = 0;
|
| 1756 | if (err > 0) {
|
| 1757 | signo = SIGCHLD;
|
| 1758 | err = 0;
|
| 1759 | if (uru) {
|
| 1760 |
|
| 1761 | if (COMPAT_USE_64BIT_TIME)
|
| 1762 | err = copy_to_user(uru, &ru, sizeof(ru));
|
| 1763 | else
|
| 1764 | err = put_compat_rusage(&ru, uru);
|
| 1765 | if (err)
|
| 1766 | return -EFAULT;
|
| 1767 | }
|
| 1768 | }
|
| 1769 |
|
| 1770 | if (!infop)
|
| 1771 | return err;
|
| 1772 |
|
| 1773 | if (!user_write_access_begin(infop, sizeof(*infop)))
|
| 1774 | return -EFAULT;
|
| 1775 |
|
| 1776 | unsafe_put_user(signo, &infop->si_signo, Efault);
|
| 1777 | unsafe_put_user(0, &infop->si_errno, Efault);
|
| 1778 | unsafe_put_user(info.cause, &infop->si_code, Efault);
|
| 1779 | unsafe_put_user(info.pid, &infop->si_pid, Efault);
|
| 1780 | unsafe_put_user(info.uid, &infop->si_uid, Efault);
|
| 1781 | unsafe_put_user(info.status, &infop->si_status, Efault);
|
| 1782 | user_write_access_end();
|
| 1783 | return err;
|
| 1784 | Efault:
|
| 1785 | user_write_access_end();
|
| 1786 | return -EFAULT;
|
| 1787 | }
|
| 1788 | #endif
|
| 1789 |
|
| 1790 | |
| 1791 | * thread_group_exited - check that a thread group has exited
|
| 1792 | * @pid: tgid of thread group to be checked.
|
| 1793 | *
|
| 1794 | * Test if the thread group represented by tgid has exited (all
|
| 1795 | * threads are zombies, dead or completely gone).
|
| 1796 | *
|
| 1797 | * Return: true if the thread group has exited. false otherwise.
|
| 1798 |
|
| 1799 | bool thread_group_exited(struct pid *pid)
|
| 1800 | {
|
| 1801 | struct task_struct *task;
|
| 1802 | bool exited;
|
| 1803 |
|
| 1804 | rcu_read_lock();
|
| 1805 | task = pid_task(pid, PIDTYPE_PID);
|
| 1806 | exited = !task ||
|
| 1807 | (READ_ONCE(task->exit_state) && thread_group_empty(task));
|
| 1808 | rcu_read_unlock();
|
| 1809 |
|
| 1810 | return exited;
|
| 1811 | }
|
| 1812 | EXPORT_SYMBOL(thread_group_exited);
|
| 1813 |
|
| 1814 | __weak void abort(void)
|
| 1815 | {
|
| 1816 | BUG();
|
| 1817 |
|
| 1818 |
|
| 1819 | panic("Oops failed to kill thread");
|
| 1820 | }
|
| 1821 | EXPORT_SYMBOL(abort);
|