[PATCH 3.11 016/272] drm/radeon/vm: don't attempt to update ptes if ib allocation fails

[Luis Henriques]

3.11.10.1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Deucher <alexander.deucher at amd.com>

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