From: Jan Beulich <JBeulich@suse.com>
Date: Mon, 24 Oct 2016 15:05:18 +0000 (-0600)
Subject: xenbus: check return value of xenbus_scanf()
X-Git-Tag: v4.9-rc3~40^2
X-Git-Url: https://repo.jachan.dev/linux.git/commitdiff_plain/c251f15c7dbf2cb72e7b2b282020b41f4e4d3665

xenbus: check return value of xenbus_scanf()

Don't ignore errors here: Set backend state to unknown when
unsuccessful.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---

diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 611a23119675..6d40a972ffb2 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -335,7 +335,9 @@ static int backend_state;
 static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
 					const char **v, unsigned int l)
 {
-	xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i", &backend_state);
+	if (xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i",
+			 &backend_state) != 1)
+		backend_state = XenbusStateUnknown;
 	printk(KERN_DEBUG "XENBUS: backend %s %s\n",
 			v[XS_WATCH_PATH], xenbus_strstate(backend_state));
 	wake_up(&backend_state_wq);