diff options
| -rw-r--r-- | include/linux/sched.h | 2 | ||||
| -rw-r--r-- | include/linux/tracehook.h | 52 | ||||
| -rw-r--r-- | kernel/exit.c | 26 | ||||
| -rw-r--r-- | kernel/signal.c | 10 |
4 files changed, 69 insertions, 21 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index adb8077dc46..a95d84d0da9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1796,7 +1796,7 @@ extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_ extern int kill_pgrp(struct pid *pid, int sig, int priv); extern int kill_pid(struct pid *pid, int sig, int priv); extern int kill_proc_info(int, struct siginfo *, pid_t); -extern void do_notify_parent(struct task_struct *, int); +extern int do_notify_parent(struct task_struct *, int); extern void force_sig(int, struct task_struct *); extern void force_sig_specific(int, struct task_struct *); extern int send_sig(int, struct task_struct *, int); diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 6dc428dd2f3..4c50e1b5734 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -471,4 +471,56 @@ static inline int tracehook_notify_jctl(int notify, int why) return notify || (current->ptrace & PT_PTRACED); } +/** + * tracehook_notify_death - task is dead, ready to notify parent + * @task: @current task now exiting + * @death_cookie: value to pass to tracehook_report_death() + * @group_dead: nonzero if this was the last thread in the group to die + * + * Return the signal number to send our parent with do_notify_parent(), or + * zero to send no signal and leave a zombie, or -1 to self-reap right now. + * + * Called with write_lock_irq(&tasklist_lock) held. + */ +static inline int tracehook_notify_death(struct task_struct *task, + void **death_cookie, int group_dead) +{ + if (task->exit_signal == -1) + return task->ptrace ? SIGCHLD : -1; + + /* + * If something other than our normal parent is ptracing us, then + * send it a SIGCHLD instead of honoring exit_signal. exit_signal + * only has special meaning to our real parent. + */ + if (thread_group_empty(task) && !ptrace_reparented(task)) + return task->exit_signal; + + return task->ptrace ? SIGCHLD : 0; +} + +/** + * tracehook_report_death - task is dead and ready to be reaped + * @task: @current task now exiting + * @signal: signal number sent to parent, or 0 or -1 + * @death_cookie: value passed back from tracehook_notify_death() + * @group_dead: nonzero if this was the last thread in the group to die + * + * Thread has just become a zombie or is about to self-reap. If positive, + * @signal is the signal number just sent to the parent (usually %SIGCHLD). + * If @signal is -1, this thread will self-reap. If @signal is 0, this is + * a delayed_group_leader() zombie. The @death_cookie was passed back by + * tracehook_notify_death(). + * + * If normal reaping is not inhibited, @task->exit_state might be changing + * in parallel. + * + * Called without locks. + */ +static inline void tracehook_report_death(struct task_struct *task, + int signal, void *death_cookie, + int group_dead) +{ +} + #endif /* <linux/tracehook.h> */ diff --git a/kernel/exit.c b/kernel/exit.c index da28745f7c3..6cdf60712bd 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -885,7 +885,8 @@ static void forget_original_parent(struct task_struct *father) */ static void exit_notify(struct task_struct *tsk, int group_dead) { - int state; + int signal; + void *cookie; /* * This does two things: @@ -922,22 +923,11 @@ static void exit_notify(struct task_struct *tsk, int group_dead) !capable(CAP_KILL)) tsk->exit_signal = SIGCHLD; - /* If something other than our normal parent is ptracing us, then - * send it a SIGCHLD instead of honoring exit_signal. exit_signal - * only has special meaning to our real parent. - */ - if (!task_detached(tsk) && thread_group_empty(tsk)) { - int signal = ptrace_reparented(tsk) ? - SIGCHLD : tsk->exit_signal; - do_notify_parent(tsk, signal); - } else if (tsk->ptrace) { - do_notify_parent(tsk, SIGCHLD); - } + signal = tracehook_notify_death(tsk, &cookie, group_dead); + if (signal > 0) + signal = do_notify_parent(tsk, signal); - state = EXIT_ZOMBIE; - if (task_detached(tsk) && likely(!tsk->ptrace)) - state = EXIT_DEAD; - tsk->exit_state = state; + tsk->exit_state = signal < 0 ? EXIT_DEAD : EXIT_ZOMBIE; /* mt-exec, de_thread() is waiting for us */ if (thread_group_leader(tsk) && @@ -947,8 +937,10 @@ static void exit_notify(struct task_struct *tsk, int group_dead) 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 (state == EXIT_DEAD) + if (signal < 0) release_task(tsk); } diff --git a/kernel/signal.c b/kernel/signal.c index e9e699f4b1b..0e862d3130f 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1326,9 +1326,11 @@ static inline void __wake_up_parent(struct task_struct *p, /* * Let a parent know about the death of a child. * For a stopped/continued status change, use do_notify_parent_cldstop instead. + * + * Returns -1 if our parent ignored us and so we've switched to + * self-reaping, or else @sig. */ - -void do_notify_parent(struct task_struct *tsk, int sig) +int do_notify_parent(struct task_struct *tsk, int sig) { struct siginfo info; unsigned long flags; @@ -1399,12 +1401,14 @@ void do_notify_parent(struct task_struct *tsk, int sig) */ tsk->exit_signal = -1; if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) - sig = 0; + sig = -1; } if (valid_signal(sig) && sig > 0) __group_send_sig_info(sig, &info, tsk->parent); __wake_up_parent(tsk, tsk->parent); spin_unlock_irqrestore(&psig->siglock, flags); + + return sig; } static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |