[PATCH] drm/radeon: guard call to radeon_fence_ref against NULL pointers

[Nicolai HÃhnle]

Candidate fix for a kernel oops that was introduced by the backport of
commit 954605ca3 "drm/radeon: hold reference to fences in radeon_sa_bo_new"
to kernels where radeon does not use the common fence implementation for
fences.

Reported-by: Lutz Euler <lutz.euler@xxxxxxxxxx>
Signed-off-by: Nicolai HÃhnle <nicolai.haehnle@xxxxxxx>
---
 drivers/gpu/drm/radeon/radeon_sa.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_sa.c b/drivers/gpu/drm/radeon/radeon_sa.c
index 197b157..7d11901 100644
--- a/drivers/gpu/drm/radeon/radeon_sa.c
+++ b/drivers/gpu/drm/radeon/radeon_sa.c
@@ -349,8 +349,10 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 			/* see if we can skip over some allocations */
 		} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));
 
-		for (i = 0; i < RADEON_NUM_RINGS; ++i)
-			radeon_fence_ref(fences[i]);
+		for (i = 0; i < RADEON_NUM_RINGS; ++i) {
+			if (fences[i])
+				radeon_fence_ref(fences[i]);
+		}
 
 		spin_unlock(&sa_manager->wq.lock);
 		r = radeon_fence_wait_any(rdev, fences, false);
-- 
2.5.0


--------------090506060305070802030409--