RDMA/amso1100: Add check if cache memory was allocated before freeing it

There is a path in handle_vq() where kmem_cache_free() can be called
with pointer to a local variable.  It can happen if vq_repbuf_alloc()
failed to allocate memory from cache and req is NULL.

The patch adds check if cache memory was allocated before freeing it.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Svetlana Mavrina <another.karnil@gmail.com>
Reviewed-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/amso1100/c2_intr.c b/drivers/infiniband/hw/amso1100/c2_intr.c
index 8951db4ae29d..3a17d9b36dba 100644
--- a/drivers/infiniband/hw/amso1100/c2_intr.c
+++ b/drivers/infiniband/hw/amso1100/c2_intr.c
@@ -169,7 +169,8 @@ static void handle_vq(struct c2_dev *c2dev, u32 mq_index)
                  * We should never get here, as the adapter should
                  * never send us a reply that we're not expecting.
                  */
-                vq_repbuf_free(c2dev, host_msg);
+                if (reply_msg != NULL)
+                        vq_repbuf_free(c2dev, host_msg);
                 pr_debug("handle_vq: UNEXPECTEDLY got NULL req\n");
                 return;
         }