[PATCH v1] drm/radeon: fix memory leak in radeon_ring_restore() on lock failure

[Yuho Choi]

radeon_ring_restore() takes ownership of the data buffer allocated by
radeon_ring_backup(). The caller (radeon_gpu_reset()) only frees it in
the non-restore branch; in the restore branch it relies on
radeon_ring_restore() to free it.

If radeon_ring_lock() fails, the function returned early without calling
kvfree(data), leaking the ring backup buffer on every GPU reset that
fails at the lock stage. During repeated GPU resets this causes
cumulative kernel memory exhaustion.

Free data before returning the error.

Fixes: 55d7c22192be ("drm/radeon: implement ring saving on reset v4")
Signed-off-by: Yuho Choi <dbgh9129@xxxxxxxxx>
---
 drivers/gpu/drm/radeon/radeon_ring.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 581ae20c46e4b..a5dff072c1ac0 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -356,8 +356,10 @@ int radeon_ring_restore(struct radeon_device *rdev, struct radeon_ring *ring,
 
 	/* restore the saved ring content */
 	r = radeon_ring_lock(rdev, ring, size);
-	if (r)
+	if (r) {
+		kvfree(data);
 		return r;
+	}
 
 	for (i = 0; i < size; ++i) {
 		radeon_ring_write(ring, data[i]);
-- 
2.50.1 (Apple Git-155)