Re: [PATCH v2] hw/virtio/vhost-shadow-virtqueue: Silence GCC error "maybe-uninitialized"

[B]

Am 20. September 2022 05:29:25 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>Am 10. September 2022 15:11:17 UTC schrieb Bernhard Beschow 
><shentey@gmail.com>:
>>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 <shentey@gmail.com>
>>---
>
>Ping

Ping2

>
>> 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) {
>