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>
OraBug: 26662731

(cherry picked from commit 2d4456c73a487abe53863e10641c2f73537edf5c)
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 080292b3f83f52ba391f30e75f872ee58b924b06..79b0a9fea347e7d7d9961bd4288218e1e986f340 100644 (file)
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -508,11 +508,13 @@ 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;