Dan Carpenter reported a missing NULL check.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 drivers/block/zram/zram_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index ea06f4d7b623..61b30c671a56 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -760,6 +760,9 @@ static void release_wb_req(struct zram_wb_req *req)
 
 static void release_wb_ctl(struct zram_wb_ctl *wb_ctl)
 {
+	if (!wb_ctl)
+		return;
+
 	/* We should never have inflight requests at this point */
 	WARN_ON(!list_empty(&wb_ctl->inflight_reqs));
 
-- 
2.52.0.rc1.455.g30608eb744-goog