From: Li Zefan <lizf@cn.fujitsu.com>
Date: Fri, 6 Feb 2009 08:17:19 +0000 (+0000)
Subject: fork.c: fix NULL pointer dereference when nr_threads == threads-max
X-Git-Tag: v2.6.29-rc4~18
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=04ec93fe9bc98e3bd8560f79f56fed66dfae40d5;p=platform%2Fupstream%2Fkernel-adaptation-pc.git

fork.c: fix NULL pointer dereference when nr_threads == threads-max

I happened to forked lots of processes, and hit NULL pointer dereference.
It is because in copy_process() after checking max_threads, 0 is returned
but not -EAGAIN.

The bug is introduced by "CRED: Detach the credentials from task_struct"
(commit f1752eec6145c97163dbce62d17cf5d928e28a27).

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/fork.c b/kernel/fork.c
index 242a706..6d5dbb7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1005,6 +1005,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	 * triggers too late. This doesn't hurt, the check is only there
 	 * to stop root fork bombs.
 	 */
+	retval = -EAGAIN;
 	if (nr_threads >= max_threads)
 		goto bad_fork_cleanup_count;