[Qemu-devel] [PATCH 5/5] virtio-blk: Do not segfault fault if failed to initialize dataplane

[Kevin Wolf <kwolf@redhat.com>]

From: Dunrong Huang <huangdr@cloud-times.com>

$ ~/usr/bin/qemu-system-x86_64 -enable-kvm -m 1024 -drive if=none,id=drive0,cache=none,aio=native,format=raw,file=/root/Image/centos-6.4.raw -device virtio-blk-pci,drive=drive0,scsi=off,x-data-plane=on,config-wce=on # make dataplane fail to initialize
qemu-system-x86_64: -device virtio-blk-pci,drive=drive0,scsi=off,x-data-plane=on,config-wce=on: device is incompatible with x-data-plane, use config-wce=off
*** glibc detected *** /root/usr/bin/qemu-system-x86_64: free(): invalid pointer: 0x00007f001fef12f8 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7d776)[0x7f00153a5776]
/root/usr/bin/qemu-system-x86_64(+0x2c34ec)[0x7f001cf5b4ec]
/root/usr/bin/qemu-system-x86_64(+0x342f9a)[0x7f001cfdaf9a]
/root/usr/bin/qemu-system-x86_64(+0x33694e)[0x7f001cfce94e]
....................

 (gdb) bt
 #0  0x00007f3bf3a12015 in raise () from /lib64/libc.so.6
 #1  0x00007f3bf3a1348b in abort () from /lib64/libc.so.6
 #2  0x00007f3bf3a51a4e in __libc_message () from /lib64/libc.so.6
 #3  0x00007f3bf3a57776 in malloc_printerr () from /lib64/libc.so.6
 #4  0x00007f3bfb60d4ec in free_and_trace (mem=0x7f3bfe0129f8) at vl.c:2786
 #5  0x00007f3bfb68cf9a in virtio_cleanup (vdev=0x7f3bfe0129f8) at /root/Develop/QEMU/qemu/hw/virtio.c:900
 #6  0x00007f3bfb68094e in virtio_blk_device_init (vdev=0x7f3bfe0129f8) at /root/Develop/QEMU/qemu/hw/virtio-blk.c:666
 #7  0x00007f3bfb68dadf in virtio_device_init (qdev=0x7f3bfe0129f8) at /root/Develop/QEMU/qemu/hw/virtio.c:1092
 #8  0x00007f3bfb50da46 in device_realize (dev=0x7f3bfe0129f8, err=0x7fff479c9258) at hw/qdev.c:176
.............................

In virtio_blk_device_init(), the memory which vdev point to is a static
member of "struct VirtIOBlkPCI", not heap memory, and it does not
get freed. So we shoule use virtio_common_cleanup() to clean this VirtIODevice
rather than virtio_cleanup(), which attempts to free the vdev.

This error was introduced by commit 05ff686536f408ba6e8426b1b54d25bd3379fda2
recently.

Signed-off-by: Dunrong Huang <huangdr@cloud-times.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/virtio-blk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index e6f8875..f2143fd 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -663,7 +663,7 @@ static int virtio_blk_device_init(VirtIODevice *vdev)
     s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output);
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
     if (!virtio_blk_data_plane_create(vdev, blk, &s->dataplane)) {
-        virtio_cleanup(vdev);
+        virtio_common_cleanup(vdev);
         return -1;
     }
 #endif
-- 
1.8.1.4