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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2015-02-11 15:01:13 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2015-02-11 15:03:14 +1030 |
| commit | 5e05bf5833eb3dd97b6b6a52301d81e033714cb3 (patch) | |
| tree | 09d60b2da7bc9ac8d7179ee18d100a48b9a126a4 /drivers/virtio | |
| parent | 1862ee22ce2e28087299aebb6556a5cdc122d0ef (diff) | |
| download | lwn-5e05bf5833eb3dd97b6b6a52301d81e033714cb3.tar.gz lwn-5e05bf5833eb3dd97b6b6a52301d81e033714cb3.zip | |
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')
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 6 |
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; } |