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From 7940a4b551e845a34409ad79a6250c5ea2f97df6 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 11 Jul 2014 14:21:10 +0200
Subject: [PATCH 30/43] usb: initialize libusb_device to avoid crash

Message-id: <1405088470-24115-38-git-send-email-kraxel@redhat.com>
Patchwork-id: 59842
O-Subject: [RHEL-7.1 qemu-kvm PATCH 37/37] usb: initialize libusb_device to avoid crash
Bugzilla: 1111450
RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

From: Jincheng Miao <jmiao@redhat.com>

If libusb_get_device_list() fails, the uninitialized local variable
libusb_device would be passed to libusb_free_device_list(), that
will cause a crash, like:
(gdb) bt
 #0  0x00007fbbb4bafc10 in pthread_mutex_lock () from /lib64/libpthread.so.0
 #1  0x00007fbbb233e653 in libusb_unref_device (dev=0x6275682d627375)
     at core.c:902
 #2  0x00007fbbb233e739 in libusb_free_device_list (list=0x7fbbb6e8436e,
     unref_devices=<optimized out>) at core.c:653
 #3  0x00007fbbb6cd80a4 in usb_host_auto_check (unused=unused@entry=0x0)
     at hw/usb/host-libusb.c:1446
 #4  0x00007fbbb6cd8525 in usb_host_initfn (udev=0x7fbbbd3c5670)
     at hw/usb/host-libusb.c:912
 #5  0x00007fbbb6cc123b in usb_device_init (dev=0x7fbbbd3c5670)
     at hw/usb/bus.c:106
 ...

So initialize libusb_device at the begin time.

Signed-off-by: Jincheng Miao <jmiao@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 3ce21445387c64032a21ae73c995195307a28a36)
---
 hw/usb/host-libusb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/usb/host-libusb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index 8510902..ef3dd5f 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -1384,7 +1384,7 @@ static void usb_host_auto_check(void *unused)
 {
     struct USBHostDevice *s;
     struct USBAutoFilter *f;
-    libusb_device **devs;
+    libusb_device **devs = NULL;
     struct libusb_device_descriptor ddesc;
     int unconnected = 0;
     int i, n;
@@ -1485,7 +1485,7 @@ static void usb_host_auto_check(void *unused)
 
 void usb_host_info(Monitor *mon, const QDict *qdict)
 {
-    libusb_device **devs;
+    libusb_device **devs = NULL;
     struct libusb_device_descriptor ddesc;
     char port[16];
     int i, n;
-- 
1.8.3.1