From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Tue, 3 Nov 2009 11:42:45 +0000 (+0800)
Subject: ring-buffer: Synchronize resizing buffer with reader lock
X-Git-Tag: v2.6.32-rc7~74^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7112949f6a4cd6883d66c882d568c2197321de6;p=pandora-kernel.git

ring-buffer: Synchronize resizing buffer with reader lock

We got a sudden panic when we reduced the size of the
ringbuffer.

We can reproduce the panic by the following steps:

echo 1 > events/sched/enable
cat trace_pipe > /dev/null &

while ((1))
do
echo 12000 > buffer_size_kb
echo 512 > buffer_size_kb
done

(not more than 5 seconds, panic ...)

Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4AF01735.9060409@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---

Reading git-diff-tree failed