virtio: fix balloon without VIRTIO_BALLOON_F_STATS_VQ
When running under qemu-kvm-0.11.0:
BUG: unable to handle kernel paging request at
56e58955
...
Process vballoon (pid: 1297, ti=
c7976000 task=
c70a6ca0 task.ti=c7
...
Call Trace:
[<
c88253a3>] ? balloon+0x1b3/0x440 [virtio_balloon]
[<
c041c2d7>] ? schedule+0x327/0x9d0
[<
c88251f0>] ? balloon+0x0/0x440 [virtio_balloon]
[<
c014a2d4>] ? kthread+0x74/0x80
[<
c014a260>] ? kthread+0x0/0x80
[<
c0103b36>] ? kernel_thread_helper+0x6/0x30
need_stats_update should be zero-initialized.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Adam Litke <agl@us.ibm.com>