do_wait: cleanup delay_group_leader() usage
eligible_child() == 2 means delay_group_leader(). With the previous patch
this only matters for EXIT_ZOMBIE task, we can move that special check to
the only place it is really needed.
Also, with this patch we don't skip security_task_wait() for the group
leaders in a non-empty thread group. I don't really understand the exact
semantics of security_task_wait(), but imho this change is a bugfix.
Also rearrange the code a bit to kill an ugly "check_continued" backdoor.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index 190a4cd..9ee229e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1140,12 +1140,6 @@
if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
&& !(options & __WALL))
return 0;
- /*
- * Do not consider thread group leaders that are
- * in a non-empty thread group:
- */
- if (delay_group_leader(p))
- return 2;
err = security_task_wait(p);
if (err)
@@ -1497,10 +1491,9 @@
tsk = current;
do {
struct task_struct *p;
- int ret;
list_for_each_entry(p, &tsk->children, sibling) {
- ret = eligible_child(pid, options, p);
+ int ret = eligible_child(pid, options, p);
if (!ret)
continue;
@@ -1524,19 +1517,17 @@
retval = wait_task_stopped(p,
(options & WNOWAIT), infop,
stat_addr, ru);
- } else if (p->exit_state == EXIT_ZOMBIE) {
+ } else if (p->exit_state == EXIT_ZOMBIE &&
+ !delay_group_leader(p)) {
/*
- * Eligible but we cannot release it yet:
+ * We don't reap group leaders with subthreads.
*/
- if (ret == 2)
- goto check_continued;
if (!likely(options & WEXITED))
continue;
retval = wait_task_zombie(p,
(options & WNOWAIT), infop,
stat_addr, ru);
} else if (p->exit_state != EXIT_DEAD) {
-check_continued:
/*
* It's running now, so it might later
* exit, stop, or stop and then continue.