The patch titled
tracehook: fix exit_signal=0 case
has been removed from the -mm tree. Its filename was
tracehook-fix-exit_signal=0-case.patch
This patch was dropped because it was merged into mainline or a subsystem tree
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
origin.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
