[PATCH] accel/rocket: Fix use-after-free in rocket_ioctl_create_bo()

[Wentao Liang]

If drm_gem_handle_create() fails, it takes and then releases its handle
reference internally, leaving the creator's reference as the only one
held.  The drm_gem_object_put() then drops that last reference, freeing
the object via rocket_gem_bo_free(), and the subsequent goto err makes
drm_gem_shmem_object_free() run on the already freed object.

Return directly on the error instead: the put has already released
everything the function acquired at this point, so there is nothing
left to clean up on the err path.

Fixes: 658ebeac3351 ("accel/rocket: Add IOCTL for BO creation")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/accel/rocket/rocket_gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/accel/rocket/rocket_gem.c b/drivers/accel/rocket/rocket_gem.c
index 91095d1b3066..521819041475 100644
--- a/drivers/accel/rocket/rocket_gem.c
+++ b/drivers/accel/rocket/rocket_gem.c
@@ -82,7 +82,7 @@ int rocket_ioctl_create_bo(struct drm_device *dev, void *data, struct drm_file *
 	ret = drm_gem_handle_create(file, gem_obj, &args->handle);
 	drm_gem_object_put(gem_obj);
 	if (ret)
-		goto err;
+		return ret;
 
 	sgt = drm_gem_shmem_get_pages_sgt(shmem_obj);
 	if (IS_ERR(sgt)) {
-- 
2.34.1