Messages in this thread Patch in this message | | | From | Minchan Kim <> | Subject | [PATCH 1/2] virtio_balloon: fix race by fill and leak | Date | Mon, 28 Dec 2015 08:35:12 +0900 |
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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@vger.kernel.org> Signed-off-by: Minchan Kim <minchan@kernel.org> --- 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 7efc32945810..7d3e5d0e9aa4 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -209,8 +209,8 @@ 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; } -- 1.9.1
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