[3.11.y.z extended stable] Patch "rbd: fix null dereference in dout" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    rbd: fix null dereference in dout

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From c918635de211e9bd531d0313be625fb79ac67035 Mon Sep 17 00:00:00 2001
From: Josh Durgin <josh.durgin at inktank.com>
Date: Wed, 28 Aug 2013 17:08:10 -0700
Subject: rbd: fix null dereference in dout

commit c35455791c1131e7ccbf56ea6fbdd562401c2ce2 upstream.

The order parameter is sometimes NULL in _rbd_dev_v2_snap_size(), but
the dout() always derefences it. Move this to another dout() protected
by a check that order is non-NULL.

Signed-off-by: Josh Durgin <josh.durgin at inktank.com>
Reviewed-by: Sage Weil <sage at inktank.com>
Reviewed-by: Alex Elder <alex.elder at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/block/rbd.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 0ab2829..853e622 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3702,12 +3702,14 @@ static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
 	if (ret < sizeof (size_buf))
 		return -ERANGE;

-	if (order)
+	if (order) {
 		*order = size_buf.order;
+		dout("  order %u", (unsigned int)*order);
+	}
 	*snap_size = le64_to_cpu(size_buf.size);

-	dout("  snap_id 0x%016llx order = %u, snap_size = %llu\n",
-		(unsigned long long)snap_id, (unsigned int)*order,
+	dout("  snap_id 0x%016llx snap_size = %llu\n",
+		(unsigned long long)snap_id,
 		(unsigned long long)*snap_size);

 	return 0;
--
1.8.3.2