From ab5fb8f34c93661bb19b62e4ed3592fb53cd6b36 Mon Sep 17 00:00:00 2001
From: Guannan Ren <gren@redhat.com>
Date: Fri, 11 May 2012 14:29:15 +0800
Subject: [PATCH] usb: fix crash when failing to attach a second usb device

when failing to attach another usb device to a domain for some reason
which has one use device attached before, the libvirtd crashed.
The crash is caused by null-pointer dereference error in invoking
usbDeviceListSteal passed in NULL value usb variable.
commit 05abd1507d66aabb6cad12eeafeb4c4d1911c585 introduces the bug.
---
 src/qemu/qemu_hotplug.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index ad31eba630..9b608162fe 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1213,7 +1213,8 @@ error:
 
 cleanup:
     usbDeviceListFree(list);
-    usbDeviceListSteal(driver->activeUsbHostdevs, usb);
+    if (usb)
+        usbDeviceListSteal(driver->activeUsbHostdevs, usb);
     return -1;
 }
 
-- 
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