xen/pvcalls: check for xenbus_read() errors

Smatch complains that "len" is uninitialized if xenbus_read() fails so
let's add some error handling.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 40caa92bff33deaebf1bf01aac44571453660c0f..afa3f1b5d807646dc949b410b1f00c327b9825fb 100644 (file)
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -1128,6 +1128,8 @@ static int pvcalls_front_probe(struct xenbus_device *dev,
        }
 
        versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
+       if (IS_ERR(versions))
+               return PTR_ERR(versions);
        if (!len)
                return -EINVAL;
        if (strcmp(versions, "1")) {