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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2015-02-11 15:01:13 +1030
committerRusty Russell <rusty@rustcorp.com.au>2015-02-11 15:03:14 +1030
commit5e05bf5833eb3dd97b6b6a52301d81e033714cb3 (patch)
tree09d60b2da7bc9ac8d7179ee18d100a48b9a126a4 /drivers/virtio/virtio_ring.c
parent1862ee22ce2e28087299aebb6556a5cdc122d0ef (diff)
downloadlinux-5e05bf5833eb3dd97b6b6a52301d81e033714cb3.tar.bz2
virtio: Avoid possible kernel panic if DEBUG is enabled.
The virtqueue_add() calls START_USE() upon entry. The virtqueue_kick() is called if vq->num_added == (1 << 16) - 1 before calling END_USE(). The virtqueue_kick_prepare() called via virtqueue_kick() calls START_USE() upon entry, and will call panic() if DEBUG is enabled. Move this virtqueue_kick() call to after END_USE() call. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/virtio/virtio_ring.c')
-rw-r--r--drivers/virtio/virtio_ring.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 95b9661554d1..096b857e7b75 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -244,14 +244,14 @@ static inline int virtqueue_add(struct virtqueue *_vq,
vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) + 1);
vq->num_added++;
+ pr_debug("Added buffer head %i to %p\n", head, vq);
+ END_USE(vq);
+
/* This is very unlikely, but theoretically possible. Kick
* just in case. */
if (unlikely(vq->num_added == (1 << 16) - 1))
virtqueue_kick(_vq);
- pr_debug("Added buffer head %i to %p\n", head, vq);
- END_USE(vq);
-
return 0;
}