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| author | Minchan Kim <minchan@kernel.org> | 2015-12-28 08:35:12 +0900 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2016-02-02 19:09:32 +0000 |
| commit | 9f0f48350a29b198a3d8c530ce8376c3346f5151 (patch) | |
| tree | 1fc601eca3ea45a5cf824d9daca87f0fb738ef71 /drivers/virtio | |
| parent | 712df95de8324fb208c3e8dd147cea69f8554ffb (diff) | |
| download | linux-stable-9f0f48350a29b198a3d8c530ce8376c3346f5151.tar.gz linux-stable-9f0f48350a29b198a3d8c530ce8376c3346f5151.tar.bz2 linux-stable-9f0f48350a29b198a3d8c530ce8376c3346f5151.zip | |
virtio_balloon: fix race by fill and leak
commit f68b992bbb474641881932c61c92dcfa6f5b3689 upstream.
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.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.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 25ebe8eecdb7..eb35e3fa984a 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -193,8 +193,8 @@ static void 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_by_pfn(vb->pfns, vb->num_pfns); + mutex_unlock(&vb->balloon_lock); } static inline void update_stat(struct virtio_balloon *vb, int idx, |