From: Arnd Bergmann <arnd@arndb.de> To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de>, Minchan Kim <minchan@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Konstantin Neumoin <kneumoin@virtuozzo.com>, "Denis V. Lunev" <den@openvz.org>, Yisheng Xie <xieyisheng1@huawei.com>, Ingo Molnar <mingo@kernel.org>, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] virtio_balloon: prevent uninitialized variable use Date: Thu, 23 Mar 2017 16:17:19 +0100 [thread overview] Message-ID: <20170323151728.679684-1-arnd@arndb.de> (raw) The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized] This seems absolutely right, so we should add an extra check to prevent copying uninitialized stack data into the statistics. >From all I can tell, this has been broken since the statistics code was originally added in 2.6.34. Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 4e1191508228..cd5c54e2003d 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -254,12 +254,14 @@ static void update_balloon_stats(struct virtio_balloon *vb) available = si_mem_available(); +#ifdef CONFIG_VM_EVENT_COUNTERS update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, pages_to_bytes(events[PSWPIN])); update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, pages_to_bytes(events[PSWPOUT])); update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); +#endif update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, pages_to_bytes(i.freeram)); update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, -- 2.9.0
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de> To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com> Cc: Yisheng Xie <xieyisheng1@huawei.com>, Arnd Bergmann <arnd@arndb.de>, Konstantin Neumoin <kneumoin@virtuozzo.com>, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Minchan Kim <minchan@kernel.org>, "Denis V. Lunev" <den@openvz.org>, Andrew Morton <akpm@linux-foundation.org>, Ingo Molnar <mingo@kernel.org> Subject: [PATCH] virtio_balloon: prevent uninitialized variable use Date: Thu, 23 Mar 2017 16:17:19 +0100 [thread overview] Message-ID: <20170323151728.679684-1-arnd@arndb.de> (raw) The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized] This seems absolutely right, so we should add an extra check to prevent copying uninitialized stack data into the statistics. From all I can tell, this has been broken since the statistics code was originally added in 2.6.34. Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 4e1191508228..cd5c54e2003d 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -254,12 +254,14 @@ static void update_balloon_stats(struct virtio_balloon *vb) available = si_mem_available(); +#ifdef CONFIG_VM_EVENT_COUNTERS update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, pages_to_bytes(events[PSWPIN])); update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, pages_to_bytes(events[PSWPOUT])); update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); +#endif update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, pages_to_bytes(i.freeram)); update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, -- 2.9.0
next reply other threads:[~2017-03-23 15:17 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-23 15:17 Arnd Bergmann [this message] 2017-03-23 15:17 ` [PATCH] virtio_balloon: prevent uninitialized variable use Arnd Bergmann 2017-03-23 15:31 ` Denis V. Lunev 2017-03-23 15:31 ` Denis V. Lunev 2017-03-24 18:38 ` David Hildenbrand 2017-03-24 18:38 ` David Hildenbrand 2017-03-24 20:11 ` Ladi Prosek 2017-03-24 20:11 ` Ladi Prosek 2017-03-24 20:40 ` Arnd Bergmann 2017-03-24 20:40 ` Arnd Bergmann 2017-03-24 20:59 ` Michael S. Tsirkin 2017-03-24 20:59 ` Michael S. Tsirkin 2017-03-27 10:02 ` Ladi Prosek 2017-03-27 10:02 ` Ladi Prosek 2017-03-28 16:18 ` Michael S. Tsirkin 2017-03-28 16:18 ` Michael S. Tsirkin 2017-03-28 16:48 ` Ladi Prosek 2017-03-28 16:48 ` Ladi Prosek
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