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authorArnd Bergmann <arnd@arndb.de>2017-03-28 19:46:59 +0300
committerMichael S. Tsirkin <mst@redhat.com>2017-03-28 20:41:28 +0300
commitf0bb2d50dfcc519f06f901aac88502be6ff1df2c (patch)
tree11716cb90806e4de4adb2ae4e89334da92bb5dca /drivers/virtio
parent9646b26e85896ef0256e66649f7937f774dc18a6 (diff)
downloadlinux-f0bb2d50dfcc519f06f901aac88502be6ff1df2c.tar.xz
virtio_balloon: prevent uninitialized variable use
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> Signed-off-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_balloon.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index d9544db231ef..34adf9b9c053 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -254,12 +254,14 @@ static unsigned int 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,