exit_notify: fix kill_orphaned_pgrp() usage with mt exit
1. exit_notify() always calls kill_orphaned_pgrp(). This is wrong, we
should do this only when the whole process exits.
2. exit_notify() uses "current" as "ignored_task", obviously wrong.
Use ->group_leader instead.
Test case:
void hup(int sig)
{
printf("HUP received\n");
}
void *tfunc(void *arg)
{
sleep(2);
printf("sub-thread exited\n");
return NULL;
}
int main(int argc, char *argv[])
{
if (!fork()) {
signal(SIGHUP, hup);
kill(getpid(), SIGSTOP);
exit(0);
}
pthread_t thr;
pthread_create(&thr, NULL, tfunc, NULL);
sleep(1);
printf("main thread exited\n");
syscall(__NR_exit, 0);
return 0;
}
output:
main thread exited
HUP received
Hangup
With this patch the output is:
main thread exited
sub-thread exited
HUP received
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index 41c1eda..cd20bf0 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -750,7 +750,7 @@
* Send signals to all our closest relatives so that they know
* to properly mourn us..
*/
-static void exit_notify(struct task_struct *tsk)
+static void exit_notify(struct task_struct *tsk, int group_dead)
{
int state;
@@ -766,7 +766,8 @@
exit_task_namespaces(tsk);
write_lock_irq(&tasklist_lock);
- kill_orphaned_pgrp(tsk, NULL);
+ if (group_dead)
+ kill_orphaned_pgrp(tsk->group_leader, NULL);
/* Let father know we died
*
@@ -981,7 +982,7 @@
module_put(tsk->binfmt->module);
proc_exit_connector(tsk);
- exit_notify(tsk);
+ exit_notify(tsk, group_dead);
#ifdef CONFIG_NUMA
mpol_free(tsk->mempolicy);
tsk->mempolicy = NULL;