block: xen-blkback: add null check to avoid null pointer dereference

Add null check before calling xen_blkif_put() to avoid potential
null pointer dereference.

Addresses-Coverity-ID: 1350942
Cc: Juergen Gross <jgross@suse.com>
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 8fe61b5dc5a6..1f3dfaa54d87 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -504,11 +504,13 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
 
         dev_set_drvdata(&dev->dev, NULL);
 
-        if (be->blkif)
+        if (be->blkif) {
                 xen_blkif_disconnect(be->blkif);
 
-        /* Put the reference we set in xen_blkif_alloc(). */
-        xen_blkif_put(be->blkif);
+                /* Put the reference we set in xen_blkif_alloc(). */
+                xen_blkif_put(be->blkif);
+        }
+
         kfree(be->mode);
         kfree(be);
         return 0;