The patch titled tracehook: fix exit_signal=0 case has been added to the -mm tree. Its filename is tracehook-fix-exit_signal=0-case.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: tracehook: fix exit_signal=0 case From: Roland McGrath <roland@xxxxxxxxxx> My commit 2b2a1ff64afbadac842bbc58c5166962cf4f7664 introduced a regression (sorry about that) for the odd case of exit_signal=0 (e.g. clone_flags=0). This is not a normal use, but it's used by a case in the glibc test suite. Dying with exit_signal=0 sends no signal, but it's supposed to wake up a parent's blocked wait*() calls (unlike the delayed_group_leader case). This fixes tracehook_notify_death() and its caller to distinguish a "signal 0" wakeup from the delayed_group_leader case (with no wakeup). Signed-off-by: Roland McGrath <roland@xxxxxxxxxx> Cc: Ulrich Drepper <drepper@xxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/tracehook.h | 21 +++++++++++++-------- kernel/exit.c | 6 +++--- 2 files changed, 16 insertions(+), 11 deletions(-) diff -puN include/linux/tracehook.h~tracehook-fix-exit_signal=0-case include/linux/tracehook.h --- a/include/linux/tracehook.h~tracehook-fix-exit_signal=0-case +++ a/include/linux/tracehook.h @@ -493,16 +493,21 @@ static inline int tracehook_notify_jctl( * @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. + * A return value >= 0 means call do_notify_parent() with that signal + * number. Negative return value can be %DEATH_REAP to self-reap right + * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our + * parent. Note that a return value of 0 means a do_notify_parent() call + * that sends no signal, but still wakes up a parent blocked in wait*(). * * Called with write_lock_irq(&tasklist_lock) held. */ +#define DEATH_REAP -1 +#define DEATH_DELAYED_GROUP_LEADER -2 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; + return task->ptrace ? SIGCHLD : DEATH_REAP; /* * If something other than our normal parent is ptracing us, then @@ -512,21 +517,21 @@ static inline int tracehook_notify_death if (thread_group_empty(task) && !ptrace_reparented(task)) return task->exit_signal; - return task->ptrace ? SIGCHLD : 0; + return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; } /** * 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 + * @signal: return value from tracheook_notify_death() * @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 @signal is %DEATH_REAP, this thread will self-reap. If @signal is + * %DEATH_DELAYED_GROUP_LEADER, 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. diff -puN kernel/exit.c~tracehook-fix-exit_signal=0-case kernel/exit.c --- a/kernel/exit.c~tracehook-fix-exit_signal=0-case +++ a/kernel/exit.c @@ -911,10 +911,10 @@ static void exit_notify(struct task_stru tsk->exit_signal = SIGCHLD; signal = tracehook_notify_death(tsk, &cookie, group_dead); - if (signal > 0) + if (signal >= 0) signal = do_notify_parent(tsk, signal); - tsk->exit_state = signal < 0 ? EXIT_DEAD : EXIT_ZOMBIE; + tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE; /* mt-exec, de_thread() is waiting for us */ if (thread_group_leader(tsk) && @@ -927,7 +927,7 @@ static void exit_notify(struct task_stru tracehook_report_death(tsk, signal, cookie, group_dead); /* If the process is dead, release it - nobody will wait for it */ - if (signal < 0) + if (signal == DEATH_REAP) release_task(tsk); } _ Patches currently in -mm which might be from roland@xxxxxxxxxx are tracehook-fix-exit_signal=0-case.patch x86-tracehook_signal_handler.patch x86-tracehook-syscall.patch x86-tracehook-asm-syscallh.patch x86-signals-use-asm-syscallh.patch x86-tracehook-tif_notify_resume.patch x86-tracehook-config_have_arch_tracehook.patch sched-do_wait_for_common-use-signal_pending_state.patch wait_task_inactive-dont-consider-task-nivcsw.patch semaphore-__down_common-use-signal_pending_state.patch posix-timers-fix-posix_timer_event-vs-dequeue_signal-race.patch posix-timers-do_schedule_next_timer-fix-the-setting-of-si_overrun.patch coredump-format_corename-dont-append-%pid-if-multi-threaded.patch kthread_bind-use-wait_task_inactivetask_uninterruptible.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html