4.4-stable review patch.  If anyone has any objections, please let me know.


From: Arnd Bergmann <a...@arndb.de>

commit f0bb2d50dfcc519f06f901aac88502be6ff1df2c upstream.

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 <a...@arndb.de>
Signed-off-by: Ladi Prosek <lpro...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

 drivers/virtio/virtio_balloon.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -239,12 +239,14 @@ static void update_balloon_stats(struct
        update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
        update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
        update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
        update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
        update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
        update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,

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