From: David Teigland <teigland@redhat.com>
Date: Thu, 5 Jun 2008 14:10:54 -0500
Subject: [dlm] check for null in device_write
Message-id: 20080605191054.GP18635@redhat.com
O-Subject: [RHEL5.3 PATCH 16/18] dlm: check for null in device_write
Bugzilla: 450136
RH-Acked-by: Bob Peterson <rpeterso@redhat.com>

bz 450136  dlm: check for null in device_write

brew build including this patch
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1344633

upstream commit in linux-next, merge pending for 2.6.27:

>From: Masatake YAMATO <yamato@redhat.com>
>Date: Wed, 28 May 2008 14:45:10 +0900
>Subject: [PATCH] dlm: check for null in device_write

If `device_write' method is called via "dlm-control",
file->private_data is NULL. (See ctl_device_open() in
user.c. ) Through proc->flags is read.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 4390df2..72f4286 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -541,7 +541,7 @@ static ssize_t device_write(struct file *file, const char __user *buf,
 
 	/* do we really need this? can a write happen after a close? */
 	if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
-	    test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
+	    (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)))
 		return -EINVAL;
 
 	sigfillset(&allsigs);