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| author | Minchan Kim <minchan@kernel.org> | 2015-12-28 08:35:12 +0900 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2016-01-12 20:47:05 +0200 |
| commit | f68b992bbb474641881932c61c92dcfa6f5b3689 (patch) | |
| tree | 56685b8b2bb7e93b7c8c96785076cf14baab50dd /drivers/virtio | |
| parent | 779a6a36961b50cd154da5705d9e6508f819cc4e (diff) | |
| download | lwn-f68b992bbb474641881932c61c92dcfa6f5b3689.tar.gz lwn-f68b992bbb474641881932c61c92dcfa6f5b3689.zip | |
virtio_balloon: fix race by fill and leak
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>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/virtio')
| -rw-r--r-- | drivers/virtio/virtio_balloon.c | 2 |
1 files changed, 1 insertions, 1 deletions
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; } |