drm/radeon: fix memory leak in radeon_ring_restore() on lock failure

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@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 581ae20c46e4b502d5db025c0ddf45112cd2a047..a5dff072c1ac035a5ac5f3fdd655ea73c371d8ce 100644 (file)
--- 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]);