#include <linux/perf_event.h>
#include <trace/events/sched.h>
#include <linux/hw_breakpoint.h>
+#include <linux/oom.h>
+#include <linux/writeback.h>
+#include <linux/shm.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
-#include "cred-internals.h"
static void exit_mm(struct task_struct * tsk);
-static void __unhash_process(struct task_struct *p)
+static void __unhash_process(struct task_struct *p, bool group_dead)
{
nr_threads--;
detach_pid(p, PIDTYPE_PID);
- if (thread_group_leader(p)) {
+ if (group_dead) {
detach_pid(p, PIDTYPE_PGID);
detach_pid(p, PIDTYPE_SID);
list_del_rcu(&p->tasks);
list_del_init(&p->sibling);
- __get_cpu_var(process_counts)--;
+ __this_cpu_dec(process_counts);
}
list_del_rcu(&p->thread_group);
}
static void __exit_signal(struct task_struct *tsk)
{
struct signal_struct *sig = tsk->signal;
+ bool group_dead = thread_group_leader(tsk);
struct sighand_struct *sighand;
-
- BUG_ON(!sig);
- BUG_ON(!atomic_read(&sig->count));
+ struct tty_struct *uninitialized_var(tty);
sighand = rcu_dereference_check(tsk->sighand,
- rcu_read_lock_held() ||
- lockdep_is_held(&tasklist_lock));
+ lockdep_tasklist_lock_is_held());
spin_lock(&sighand->siglock);
posix_cpu_timers_exit(tsk);
- if (atomic_dec_and_test(&sig->count))
+ if (group_dead) {
posix_cpu_timers_exit_group(tsk);
- else {
+ tty = sig->tty;
+ sig->tty = NULL;
+ } else {
+ /*
+ * This can only happen if the caller is de_thread().
+ * FIXME: this is the temporary hack, we should teach
+ * posix-cpu-timers to handle this case correctly.
+ */
+ if (unlikely(has_group_leader_pid(tsk)))
+ posix_cpu_timers_exit_group(tsk);
+
/*
* If there is any task waiting for the group exit
* then notify it:
*/
- if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
+ if (sig->notify_count > 0 && !--sig->notify_count)
wake_up_process(sig->group_exit_task);
if (tsk == sig->curr_target)
* We won't ever get here for the group leader, since it
* will have been the last reference on the signal_struct.
*/
- sig->utime = cputime_add(sig->utime, tsk->utime);
- sig->stime = cputime_add(sig->stime, tsk->stime);
- sig->gtime = cputime_add(sig->gtime, tsk->gtime);
+ sig->utime += tsk->utime;
+ sig->stime += tsk->stime;
+ sig->gtime += tsk->gtime;
sig->min_flt += tsk->min_flt;
sig->maj_flt += tsk->maj_flt;
sig->nvcsw += tsk->nvcsw;
sig->oublock += task_io_get_oublock(tsk);
task_io_accounting_add(&sig->ioac, &tsk->ioac);
sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
- sig = NULL; /* Marker for below. */
}
- __unhash_process(tsk);
+ sig->nr_threads--;
+ __unhash_process(tsk, group_dead);
/*
* Do this under ->siglock, we can race with another thread
* doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
*/
flush_sigqueue(&tsk->pending);
-
- tsk->signal = NULL;
tsk->sighand = NULL;
spin_unlock(&sighand->siglock);
__cleanup_sighand(sighand);
clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
- if (sig) {
+ if (group_dead) {
flush_sigqueue(&sig->shared_pending);
- taskstats_tgid_free(sig);
- /*
- * Make sure ->signal can't go away under rq->lock,
- * see account_group_exec_runtime().
- */
- task_rq_unlock_wait(tsk);
- __cleanup_signal(sig);
+ tty_kref_put(tty);
}
}
{
struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
-#ifdef CONFIG_PERF_EVENTS
- WARN_ON_ONCE(tsk->perf_event_ctxp);
-#endif
+ perf_event_delayed_put(tsk);
trace_sched_process_free(tsk);
put_task_struct(tsk);
}
struct task_struct *leader;
int zap_leader;
repeat:
- tracehook_prepare_release_task(p);
/* don't need to get the RCU readlock here - the process is dead and
* can't be modifying its own credentials. But shut RCU-lockdep up */
rcu_read_lock();
proc_flush_task(p);
write_lock_irq(&tasklist_lock);
- tracehook_finish_release_task(p);
+ ptrace_release_task(p);
__exit_signal(p);
/*
zap_leader = 0;
leader = p->group_leader;
if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
- BUG_ON(task_detached(leader));
- do_notify_parent(leader, leader->exit_signal);
/*
* If we were the last child thread and the leader has
* exited already, and the leader's parent ignores SIGCHLD,
* then we are the one who should release the leader.
- *
- * do_notify_parent() will have marked it self-reaping in
- * that case.
- */
- zap_leader = task_detached(leader);
-
- /*
- * This maintains the invariant that release_task()
- * only runs on a task in EXIT_DEAD, just for sanity.
*/
+ zap_leader = do_notify_parent(leader, leader->exit_signal);
if (zap_leader)
leader->exit_state = EXIT_DEAD;
}
return retval;
}
-static int has_stopped_jobs(struct pid *pgrp)
+static bool has_stopped_jobs(struct pid *pgrp)
{
- int retval = 0;
struct task_struct *p;
do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
- if (!task_is_stopped(p))
- continue;
- retval = 1;
- break;
+ if (p->signal->flags & SIGNAL_STOP_STOPPED)
+ return true;
} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
- return retval;
+
+ return false;
}
/*
*/
exit_mm(current);
/*
- * We don't want to have TIF_FREEZE set if the system-wide hibernation
+ * We don't want to get frozen, in case system-wide hibernation
* or suspend transition begins right now.
*/
current->flags |= (PF_NOFREEZE | PF_KTHREAD);
i = j * __NFDBITS;
if (i >= fdt->max_fds)
break;
- set = fdt->open_fds->fds_bits[j++];
+ set = fdt->open_fds[j++];
while (set) {
if (set & 1) {
struct file * file = xchg(&fdt->fd[i], NULL);
#ifdef CONFIG_MM_OWNER
/*
- * Task p is exiting and it owned mm, lets find a new owner for it
+ * A task is exiting. If it owned this mm, find a new owner for the mm.
*/
-static inline int
-mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
-{
- /*
- * If there are other users of the mm and the owner (us) is exiting
- * we need to find a new owner to take on the responsibility.
- */
- if (atomic_read(&mm->mm_users) <= 1)
- return 0;
- if (mm->owner != p)
- return 0;
- return 1;
-}
-
void mm_update_next_owner(struct mm_struct *mm)
{
struct task_struct *c, *g, *p = current;
retry:
- if (!mm_need_new_owner(mm, p))
+ /*
+ * If the exiting or execing task is not the owner, it's
+ * someone else's problem.
+ */
+ if (mm->owner != p)
+ return;
+ /*
+ * The current owner is exiting/execing and there are no other
+ * candidates. Do not leave the mm pointing to a possibly
+ * freed task structure.
+ */
+ if (atomic_read(&mm->mm_users) <= 1) {
+ mm->owner = NULL;
return;
+ }
read_lock(&tasklist_lock);
/*
tsk->mm = NULL;
up_read(&mm->mmap_sem);
enter_lazy_tlb(mm, current);
- /* We don't want this task to be frozen prematurely */
- clear_freeze_flag(tsk);
task_unlock(tsk);
mm_update_next_owner(mm);
mmput(mm);
}
/*
- * When we die, we re-parent all our children.
- * Try to give them to another thread in our thread
- * group, and if no such member exists, give it to
- * the child reaper process (ie "init") in our pid
- * space.
+ * When we die, we re-parent all our children, and try to:
+ * 1. give them to another thread in our thread group, if such a member exists
+ * 2. give it to the first ancestor process which prctl'd itself as a
+ * child_subreaper for its children (like a service manager)
+ * 3. give it to the init process (PID 1) in our pid namespace
*/
static struct task_struct *find_new_reaper(struct task_struct *father)
+ __releases(&tasklist_lock)
+ __acquires(&tasklist_lock)
{
struct pid_namespace *pid_ns = task_active_pid_ns(father);
struct task_struct *thread;
if (unlikely(pid_ns->child_reaper == father)) {
write_unlock_irq(&tasklist_lock);
- if (unlikely(pid_ns == &init_pid_ns))
- panic("Attempted to kill init!");
+ if (unlikely(pid_ns == &init_pid_ns)) {
+ panic("Attempted to kill init! exitcode=0x%08x\n",
+ father->signal->group_exit_code ?:
+ father->exit_code);
+ }
zap_pid_ns_processes(pid_ns);
write_lock_irq(&tasklist_lock);
* forget_original_parent() must move them somewhere.
*/
pid_ns->child_reaper = init_pid_ns.child_reaper;
+ } else if (father->signal->has_child_subreaper) {
+ struct task_struct *reaper;
+
+ /*
+ * Find the first ancestor marked as child_subreaper.
+ * Note that the code below checks same_thread_group(reaper,
+ * pid_ns->child_reaper). This is what we need to DTRT in a
+ * PID namespace. However we still need the check above, see
+ * http://marc.info/?l=linux-kernel&m=131385460420380
+ */
+ for (reaper = father->real_parent;
+ reaper != &init_task;
+ reaper = reaper->real_parent) {
+ if (same_thread_group(reaper, pid_ns->child_reaper))
+ break;
+ if (!reaper->signal->is_child_subreaper)
+ continue;
+ thread = reaper;
+ do {
+ if (!(thread->flags & PF_EXITING))
+ return reaper;
+ } while_each_thread(reaper, thread);
+ }
}
return pid_ns->child_reaper;
{
list_move_tail(&p->sibling, &p->real_parent->children);
- if (task_detached(p))
+ if (p->exit_state == EXIT_DEAD)
return;
/*
* If this is a threaded reparent there is no need to
p->exit_signal = SIGCHLD;
/* If it has exited notify the new parent about this child's death. */
- if (!task_ptrace(p) &&
+ if (!p->ptrace &&
p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
- do_notify_parent(p, p->exit_signal);
- if (task_detached(p)) {
+ if (do_notify_parent(p, p->exit_signal)) {
p->exit_state = EXIT_DEAD;
list_move_tail(&p->sibling, dead);
}
struct task_struct *p, *n, *reaper;
LIST_HEAD(dead_children);
- exit_ptrace(father);
-
write_lock_irq(&tasklist_lock);
+ /*
+ * Note that exit_ptrace() and find_new_reaper() might
+ * drop tasklist_lock and reacquire it.
+ */
+ exit_ptrace(father);
reaper = find_new_reaper(father);
list_for_each_entry_safe(p, n, &father->children, sibling) {
do {
t->real_parent = reaper;
if (t->parent == father) {
- BUG_ON(task_ptrace(t));
+ BUG_ON(t->ptrace);
t->parent = t->real_parent;
}
if (t->pdeath_signal)
*/
static void exit_notify(struct task_struct *tsk, int group_dead)
{
- int signal;
- void *cookie;
+ bool autoreap;
/*
* This does two things:
if (group_dead)
kill_orphaned_pgrp(tsk->group_leader, NULL);
- /* Let father know we died
- *
- * Thread signals are configurable, but you aren't going to use
- * that to send signals to arbitary processes.
- * That stops right now.
- *
- * If the parent exec id doesn't match the exec id we saved
- * when we started then we know the parent has changed security
- * domain.
- *
- * If our self_exec id doesn't match our parent_exec_id then
- * we have changed execution domain as these two values started
- * the same after a fork.
- */
- if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
- (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
- tsk->self_exec_id != tsk->parent_exec_id))
- tsk->exit_signal = SIGCHLD;
-
- signal = tracehook_notify_death(tsk, &cookie, group_dead);
- if (signal >= 0)
- signal = do_notify_parent(tsk, signal);
+ if (unlikely(tsk->ptrace)) {
+ int sig = thread_group_leader(tsk) &&
+ thread_group_empty(tsk) &&
+ !ptrace_reparented(tsk) ?
+ tsk->exit_signal : SIGCHLD;
+ autoreap = do_notify_parent(tsk, sig);
+ } else if (thread_group_leader(tsk)) {
+ autoreap = thread_group_empty(tsk) &&
+ do_notify_parent(tsk, tsk->exit_signal);
+ } else {
+ autoreap = true;
+ }
- tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
+ tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
- /* mt-exec, de_thread() is waiting for us */
- if (thread_group_leader(tsk) &&
- tsk->signal->group_exit_task &&
- tsk->signal->notify_count < 0)
+ /* mt-exec, de_thread() is waiting for group leader */
+ if (unlikely(tsk->signal->notify_count < 0))
wake_up_process(tsk->signal->group_exit_task);
-
write_unlock_irq(&tasklist_lock);
- tracehook_report_death(tsk, signal, cookie, group_dead);
-
/* If the process is dead, release it - nobody will wait for it */
- if (signal == DEATH_REAP)
+ if (autoreap)
release_task(tsk);
}
static inline void check_stack_usage(void) {}
#endif
-NORET_TYPE void do_exit(long code)
+void do_exit(long code)
{
struct task_struct *tsk = current;
int group_dead;
profile_task_exit(tsk);
- WARN_ON(atomic_read(&tsk->fs_excl));
+ WARN_ON(blk_needs_flush_plug(tsk));
if (unlikely(in_interrupt()))
panic("Aiee, killing interrupt handler!");
if (unlikely(!tsk->pid))
panic("Attempted to kill the idle task!");
- tracehook_report_exit(&code);
+ /*
+ * If do_exit is called because this processes oopsed, it's possible
+ * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
+ * continuing. Amongst other possible reasons, this is to prevent
+ * mm_release()->clear_child_tid() from writing to a user-controlled
+ * kernel address.
+ */
+ set_fs(USER_DS);
+
+ ptrace_event(PTRACE_EVENT_EXIT, code);
validate_creds_for_do_exit(tsk);
schedule();
}
- exit_irq_thread();
-
exit_signals(tsk); /* sets PF_EXITING */
/*
* tsk->flags are checked in the futex code to protect against
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
+ exit_irq_thread();
+
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
acct_update_integrals(tsk);
/* sync mm's RSS info before statistics gathering */
- sync_mm_rss(tsk, tsk->mm);
+ if (tsk->mm)
+ sync_mm_rss(tsk->mm);
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
hrtimer_cancel(&tsk->signal->real_timer);
acct_collect(code, group_dead);
if (group_dead)
tty_audit_exit();
- if (unlikely(tsk->audit_context))
- audit_free(tsk);
+ audit_free(tsk);
tsk->exit_code = code;
taskstats_exit(tsk, group_dead);
trace_sched_process_exit(tsk);
exit_sem(tsk);
+ exit_shm(tsk);
exit_files(tsk);
exit_fs(tsk);
check_stack_usage();
exit_thread();
+
+ /*
+ * Flush inherited counters to the parent - before the parent
+ * gets woken up by child-exit notifications.
+ *
+ * because of cgroup mode, must be called before cgroup_exit()
+ */
+ perf_event_exit_task(tsk);
+
cgroup_exit(tsk, 1);
if (group_dead)
/*
* FIXME: do that only when needed, using sched_exit tracepoint
*/
- flush_ptrace_hw_breakpoint(tsk);
- /*
- * Flush inherited counters to the parent - before the parent
- * gets woken up by child-exit notifications.
- */
- perf_event_exit_task(tsk);
+ ptrace_put_breakpoints(tsk);
exit_notify(tsk, group_dead);
#ifdef CONFIG_NUMA
+ task_lock(tsk);
mpol_put(tsk->mempolicy);
tsk->mempolicy = NULL;
+ task_unlock(tsk);
#endif
#ifdef CONFIG_FUTEX
if (unlikely(current->pi_state_cache))
validate_creds_for_do_exit(tsk);
preempt_disable();
+ if (tsk->nr_dirtied)
+ __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
exit_rcu();
+
+ /*
+ * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
+ * when the following two conditions become true.
+ * - There is race condition of mmap_sem (It is acquired by
+ * exit_mm()), and
+ * - SMI occurs before setting TASK_RUNINNG.
+ * (or hypervisor of virtual machine switches to other guest)
+ * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
+ *
+ * To avoid it, we have to wait for releasing tsk->pi_lock which
+ * is held by try_to_wake_up()
+ */
+ smp_mb();
+ raw_spin_unlock_wait(&tsk->pi_lock);
+
/* causes final put_task_struct in finish_task_switch(). */
tsk->state = TASK_DEAD;
+ tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
schedule();
BUG();
/* Avoid "noreturn function does return". */
EXPORT_SYMBOL_GPL(do_exit);
-NORET_TYPE void complete_and_exit(struct completion *comp, long code)
+void complete_and_exit(struct completion *comp, long code)
{
if (comp)
complete(comp);
* Take down every thread in the group. This is called by fatal signals
* as well as by sys_exit_group (below).
*/
-NORET_TYPE void
+void
do_group_exit(int exit_code)
{
struct signal_struct *sig = current->signal;
if (unlikely(wo->wo_flags & WNOWAIT)) {
int exit_code = p->exit_code;
- int why, status;
+ int why;
get_task_struct(p);
read_unlock(&tasklist_lock);
traced = ptrace_reparented(p);
/*
* It can be ptraced but not reparented, check
- * !task_detached() to filter out sub-threads.
+ * thread_group_leader() to filter out sub-threads.
*/
- if (likely(!traced) && likely(!task_detached(p))) {
+ if (likely(!traced) && thread_group_leader(p)) {
struct signal_struct *psig;
struct signal_struct *sig;
unsigned long maxrss;
spin_lock_irq(&p->real_parent->sighand->siglock);
psig = p->real_parent->signal;
sig = p->signal;
- psig->cutime =
- cputime_add(psig->cutime,
- cputime_add(tgutime,
- sig->cutime));
- psig->cstime =
- cputime_add(psig->cstime,
- cputime_add(tgstime,
- sig->cstime));
- psig->cgtime =
- cputime_add(psig->cgtime,
- cputime_add(p->gtime,
- cputime_add(sig->gtime,
- sig->cgtime)));
+ psig->cutime += tgutime + sig->cutime;
+ psig->cstime += tgstime + sig->cstime;
+ psig->cgtime += p->gtime + sig->gtime + sig->cgtime;
psig->cmin_flt +=
p->min_flt + sig->min_flt + sig->cmin_flt;
psig->cmaj_flt +=
/* We dropped tasklist, ptracer could die and untrace */
ptrace_unlink(p);
/*
- * If this is not a detached task, notify the parent.
- * If it's still not detached after that, don't release
- * it now.
+ * If this is not a sub-thread, notify the parent.
+ * If parent wants a zombie, don't release it now.
*/
- if (!task_detached(p)) {
- do_notify_parent(p, p->exit_signal);
- if (!task_detached(p)) {
- p->exit_state = EXIT_ZOMBIE;
- p = NULL;
- }
+ if (thread_group_leader(p) &&
+ !do_notify_parent(p, p->exit_signal)) {
+ p->exit_state = EXIT_ZOMBIE;
+ p = NULL;
}
write_unlock_irq(&tasklist_lock);
}
static int *task_stopped_code(struct task_struct *p, bool ptrace)
{
if (ptrace) {
- if (task_is_stopped_or_traced(p))
+ if (task_is_stopped_or_traced(p) &&
+ !(p->jobctl & JOBCTL_LISTENING))
return &p->exit_code;
} else {
if (p->signal->flags & SIGNAL_STOP_STOPPED)
return NULL;
}
-/*
- * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
- * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
- * the lock and this task is uninteresting. If we return nonzero, we have
- * released the lock and the system call should return.
+/**
+ * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
+ * @wo: wait options
+ * @ptrace: is the wait for ptrace
+ * @p: task to wait for
+ *
+ * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
+ *
+ * CONTEXT:
+ * read_lock(&tasklist_lock), which is released if return value is
+ * non-zero. Also, grabs and releases @p->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 if wait condition didn't exist and search for other wait conditions
+ * should continue. Non-zero return, -errno on failure and @p's pid on
+ * success, implies that tasklist_lock is released and wait condition
+ * search should terminate.
*/
static int wait_task_stopped(struct wait_opts *wo,
int ptrace, struct task_struct *p)
if (!ptrace && !(wo->wo_flags & WUNTRACED))
return 0;
+ if (!task_stopped_code(p, ptrace))
+ return 0;
+
exit_code = 0;
spin_lock_irq(&p->sighand->siglock);
if (!unlikely(wo->wo_flags & WNOWAIT))
*p_code = 0;
- /* don't need the RCU readlock here as we're holding a spinlock */
- uid = __task_cred(p)->uid;
+ uid = task_uid(p);
unlock_sig:
spin_unlock_irq(&p->sighand->siglock);
if (!exit_code)
}
if (!unlikely(wo->wo_flags & WNOWAIT))
p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
- uid = __task_cred(p)->uid;
+ uid = task_uid(p);
spin_unlock_irq(&p->sighand->siglock);
pid = task_pid_vnr(p);
return 0;
}
- if (likely(!ptrace) && unlikely(task_ptrace(p))) {
+ /* dead body doesn't have much to contribute */
+ if (unlikely(p->exit_state == EXIT_DEAD)) {
/*
- * This child is hidden by ptrace.
- * We aren't allowed to see it now, but eventually we will.
+ * But do not ignore this task until the tracer does
+ * wait_task_zombie()->do_notify_parent().
*/
- wo->notask_error = 0;
+ if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
+ wo->notask_error = 0;
return 0;
}
- if (p->exit_state == EXIT_DEAD)
- return 0;
+ /* slay zombie? */
+ if (p->exit_state == EXIT_ZOMBIE) {
+ /*
+ * A zombie ptracee is only visible to its ptracer.
+ * Notification and reaping will be cascaded to the real
+ * parent when the ptracer detaches.
+ */
+ if (likely(!ptrace) && unlikely(p->ptrace)) {
+ /* it will become visible, clear notask_error */
+ wo->notask_error = 0;
+ return 0;
+ }
+
+ /* we don't reap group leaders with subthreads */
+ if (!delay_group_leader(p))
+ return wait_task_zombie(wo, p);
+
+ /*
+ * Allow access to stopped/continued state via zombie by
+ * falling through. Clearing of notask_error is complex.
+ *
+ * When !@ptrace:
+ *
+ * If WEXITED is set, notask_error should naturally be
+ * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
+ * so, if there are live subthreads, there are events to
+ * wait for. If all subthreads are dead, it's still safe
+ * to clear - this function will be called again in finite
+ * amount time once all the subthreads are released and
+ * will then return without clearing.
+ *
+ * When @ptrace:
+ *
+ * Stopped state is per-task and thus can't change once the
+ * target task dies. Only continued and exited can happen.
+ * Clear notask_error if WCONTINUED | WEXITED.
+ */
+ if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
+ wo->notask_error = 0;
+ } else {
+ /*
+ * If @p is ptraced by a task in its real parent's group,
+ * hide group stop/continued state when looking at @p as
+ * the real parent; otherwise, a single stop can be
+ * reported twice as group and ptrace stops.
+ *
+ * If a ptracer wants to distinguish the two events for its
+ * own children, it should create a separate process which
+ * takes the role of real parent.
+ */
+ if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))
+ return 0;
+
+ /*
+ * @p is alive and it's gonna stop, continue or exit, so
+ * there always is something to wait for.
+ */
+ wo->notask_error = 0;
+ }
/*
- * We don't reap group leaders with subthreads.
+ * Wait for stopped. Depending on @ptrace, different stopped state
+ * is used and the two don't interact with each other.
*/
- if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
- return wait_task_zombie(wo, p);
+ ret = wait_task_stopped(wo, ptrace, p);
+ if (ret)
+ return ret;
/*
- * It's stopped or running now, so it might
- * later continue, exit, or stop again.
+ * Wait for continued. There's only one continued state and the
+ * ptracer can consume it which can confuse the real parent. Don't
+ * use WCONTINUED from ptracer. You don't need or want it.
*/
- wo->notask_error = 0;
-
- if (task_stopped_code(p, ptrace))
- return wait_task_stopped(wo, ptrace, p);
-
return wait_task_continued(wo, p);
}
projects / linux-flexiantxendom0-3.2.10.git / blobdiff