virtio-blk: Fix potential nullpointer read access in virtio_blk_data_plane_destroy

Fixes: CID 1532828
Fixes: b6948ab01d ("virtio-blk: add iothread-vq-mapping parameter")
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 6debd4401e0dacd9c93f1b7fa6f7cba13be4fd45..97a302cf4973078d660d0cab0095be2636f3292f 100644 (file)
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -152,7 +152,7 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
 void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
 {
     VirtIOBlock *vblk;
-    VirtIOBlkConf *conf = s->conf;
+    VirtIOBlkConf *conf;
 
     if (!s) {
         return;
@@ -160,6 +160,7 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
 
     vblk = VIRTIO_BLK(s->vdev);
     assert(!vblk->dataplane_started);
+    conf = s->conf;
 
     if (conf->iothread_vq_mapping_list) {
         IOThreadVirtQueueMappingList *node;