| From foo@baz Thu Dec 21 09:02:40 CET 2017 |
| From: Arnd Bergmann <arnd@arndb.de> |
| Date: Tue, 28 Mar 2017 18:46:59 +0200 |
| Subject: virtio_balloon: prevent uninitialized variable use |
| |
| From: Arnd Bergmann <arnd@arndb.de> |
| |
| |
| [ Upstream commit f0bb2d50dfcc519f06f901aac88502be6ff1df2c ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <alexander.levin@verizon.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@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 |
| @@ -253,12 +253,14 @@ static unsigned int update_balloon_stats |
| |
| 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, |
