From: Philipp Reisner <philipp.reisner@linbit.com>
Date: Thu, 20 May 2010 11:35:31 +0000 (+0200)
Subject: drbd: Null pointer deref fix to the large "multi bio rewrite"
X-Git-Tag: v2.6.35-rc1~442^2~5
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=23ce422748def9652fdc019f740cd7900fa2fe3b;p=profile%2Fcommon%2Fkernel-common.git

drbd: Null pointer deref fix to the large "multi bio rewrite"

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 461d987..bc9ab7f 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -98,6 +98,10 @@ static struct page *page_chain_del(struct page **head, int n)
 	BUG_ON(!head);
 
 	page = *head;
+
+	if (!page)
+		return NULL;
+
 	while (page) {
 		tmp = page_chain_next(page);
 		if (--n == 0)