Am 10. September 2022 15:11:17 UTC schrieb Bernhard Beschow <[email protected]>:
>GCC issues a false positive warning, resulting in build failure with -Werror:
>
> In file included from /usr/include/glib-2.0/glib.h:114,
> from src/include/glib-compat.h:32,
> from src/include/qemu/osdep.h:144,
> from ../src/hw/virtio/vhost-shadow-virtqueue.c:10:
> In function ‘g_autoptr_cleanup_generic_gfree’,
> inlined from ‘vhost_handle_guest_kick’ at
> ../src/hw/virtio/vhost-shadow-virtqueue.c:292:42:
> /usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: error: ‘elem’ may be
> used uninitialized [-Werror=maybe-uninitialized]
> 28 | g_free (*pp);
> | ^~~~~~~~~~~~
> ../src/hw/virtio/vhost-shadow-virtqueue.c: In function
> ‘vhost_handle_guest_kick’:
> ../src/hw/virtio/vhost-shadow-virtqueue.c:292:42: note: ‘elem’ was declared
> here
> 292 | g_autofree VirtQueueElement *elem;
> | ^~~~
> cc1: all warnings being treated as errors
>
>There is actually no problem since "elem" is initialized in both branches.
>Silence the warning by initializig it with "NULL".
>
>$ gcc --version
>gcc (GCC) 12.2.0
>
>Fixes: 9c2ab2f1ec333be8614cc12272d4b91960704dbe ("vhost: stop transfer elem
>ownership in vhost_handle_guest_kick")
>Signed-off-by: Bernhard Beschow <[email protected]>
>---
Ping
> hw/virtio/vhost-shadow-virtqueue.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/hw/virtio/vhost-shadow-virtqueue.c
>b/hw/virtio/vhost-shadow-virtqueue.c
>index e8e5bbc368..596d4434d2 100644
>--- a/hw/virtio/vhost-shadow-virtqueue.c
>+++ b/hw/virtio/vhost-shadow-virtqueue.c
>@@ -289,7 +289,7 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue
>*svq)
> virtio_queue_set_notification(svq->vq, false);
>
> while (true) {
>- g_autofree VirtQueueElement *elem;
>+ g_autofree VirtQueueElement *elem = NULL;
> int r;
>
> if (svq->next_guest_avail_elem) {
