tracehook: fix exit_signal=0 case

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@redhat.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index eb4d6470d1d0..38ec40630149 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -911,10 +911,10 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
                 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_struct *tsk, int group_dead)
         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);
 }