From: Guannan Ren <gren@redhat.com>
Date: Fri, 11 May 2012 06:29:15 +0000 (+0800)
Subject: usb: fix crash when failing to attach a second usb device
X-Git-Tag: v0.9.12~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab5fb8f34c93661bb19b62e4ed3592fb53cd6b36;p=thirdparty%2Flibvirt.git

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.
---

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;
 }