From: Minchan Kim <minchan@xxxxxxxxxx> This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit f68b992bbb474641881932c61c92dcfa6f5b3689 ] During my compaction-related stuff, I encountered a bug with ballooning. With repeated inflating and deflating cycle, guest memory( ie, cat /proc/meminfo | grep MemTotal) is decreased and couldn't be recovered. The reason is balloon_lock doesn't cover release_pages_balloon so struct virtio_balloon fields could be overwritten by race of fill_balloon(e,g, vb->*pfns could be critical). This patch fixes it in my test. Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- drivers/virtio/virtio_balloon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 8543c9a..89bac47 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -205,8 +205,8 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) */ if (vb->num_pfns != 0) tell_host(vb, vb->deflate_vq); - mutex_unlock(&vb->balloon_lock); release_pages_balloon(vb); + mutex_unlock(&vb->balloon_lock); return num_freed_pages; } -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html