| Message ID | 20220910151117.6665-1-shentey@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] hw/virtio/vhost-shadow-virtqueue: Silence GCC error "maybe-uninitialized" | expand |
On 9/10/22 16:11, Bernhard Beschow wrote: > 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> > --- > hw/virtio/vhost-shadow-virtqueue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) It's not a false positive, but the fix is correct. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
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> Forgot to add from v1: Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> >--- > 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) {
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 > 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) {
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) { >
Le 10/09/2022 à 17:11, Bernhard Beschow a écrit : > 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> > --- > 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) { Applied to my trivial-patches branch. Thanks, Laurent
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) {
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> --- hw/virtio/vhost-shadow-virtqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)