From: hugh@veritas.com <hugh@veritas.com>
Date: Sat, 19 Mar 2005 05:41:52 +0000 (-0800)
Subject: [PATCH] tasklist left locked
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=80f9a237983740508b1676bd56fdfd68ebe2d12d;p=thirdparty%2Fkernel%2Fstable.git

[PATCH] tasklist left locked

On 4-way SMP, about one reboot in twenty hangs while killing processes:
exit needs exclusive tasklist_lock, but something still holds read_lock.
do_signal_stop race case misses unlock, and fixing it fixes the symptom.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/kernel/signal.c b/kernel/signal.c
index 9e87ab3f8f21f..63ae3d5843903 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1728,6 +1728,7 @@ do_signal_stop(int signr)
 			 * with another processor delivering a stop signal,
 			 * then the SIGCONT that wakes us up should clear it.
 			 */
+			read_unlock(&tasklist_lock);
 			return 0;
 		}