[3.11.y.z extended stable] Patch "drm/radeon/vm: don't attempt to update ptes if ib allocation fails" has been added to staging queue

[Luis Henriques]

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

    drm/radeon/vm: don't attempt to update ptes if ib allocation fails

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

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>From 61e7f0b7d041021bd2b16cdc2d98452f1ddec926 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher at amd.com>
Date: Wed, 13 Nov 2013 15:25:35 -0500
Subject: drm/radeon/vm: don't attempt to update ptes if ib allocation fails
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 4cc948b94a222c310ae089c36718aac7a03aec90 upstream.

If we fail to allocate an indirect buffer (ib) when updating
the ptes, return an error instead of trying to use the ib.
Avoids a null pointer dereference.

Bug:
https://bugzilla.kernel.org/show_bug.cgi?id=58621

Reviewed-by: Christian König <christian.koenig at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/radeon/radeon_gart.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c
index b990b1a..3b1de72 100644
--- a/drivers/gpu/drm/radeon/radeon_gart.c
+++ b/drivers/gpu/drm/radeon/radeon_gart.c
@@ -1156,6 +1156,8 @@ int radeon_vm_bo_update_pte(struct radeon_device *rdev,
 		return -ENOMEM;

 	r = radeon_ib_get(rdev, ridx, &ib, NULL, ndw * 4);
+	if (r)
+		return r;
 	ib.length_dw = 0;

 	r = radeon_vm_update_pdes(rdev, vm, &ib, bo_va->soffset, bo_va->eoffset);
--
1.8.3.2