From 15b9f360c0316c06d37c09b02d85565edbaf9dd3 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Fri, 25 Jul 2008 01:47:39 -0700
Subject: [PATCH] coredump: zap_threads() must skip kernel threads
The main loop in zap_threads() must skip kthreads which may use the same
mm. Otherwise we "kill" this thread erroneously (for example, it can not
fork or exec after that), and the coredumping task stucks in the
TASK_UNINTERRUPTIBLE state forever because of the wrong ->core_waiters
count.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/exec.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index cd2e8c9b12494..e347e6ed1617b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1574,11 +1574,12 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
for_each_process(g) {
if (g == tsk->group_leader)
continue;
-
+ if (g->flags & PF_KTHREAD)
+ continue;
p = g;
do {
if (p->mm) {
- if (p->mm == mm) {
+ if (unlikely(p->mm == mm)) {
lock_task_sighand(p, &flags);
zap_process(p);
unlock_task_sighand(p, &flags);
--
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