diff options
| author | Mao Wenan <wenan.mao@linux.alibaba.com> | 2020-08-02 15:44:09 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-08-26 10:29:57 +0200 |
| commit | 1f49e8cefa5a313d69dedfec8e47745231914c06 (patch) | |
| tree | 9da8dfd2068a42a092567511f8bd66587a128e0c /drivers/virtio/virtio_ring.c | |
| parent | 9b5681afc9e69f7cacd769c7274f1d2a102257f7 (diff) | |
virtio_ring: Avoid loop when vq is broken in virtqueue_poll
[ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ]
The loop may exist if vq->broken is true,
virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split
will return NULL, so virtnet_poll will reschedule napi to
receive packet, it will lead cpu usage(si) to 100%.
call trace as below:
virtnet_poll
virtnet_receive
virtqueue_get_buf_ctx
virtqueue_get_buf_ctx_packed
virtqueue_get_buf_ctx_split
virtqueue_napi_complete
virtqueue_poll //return true
virtqueue_napi_schedule //it will reschedule napi
to fix this, return false if vq is broken in virtqueue_poll.
Signed-off-by: Mao Wenan <wenan.mao@linux.alibaba.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/1596354249-96204-1-git-send-email-wenan.mao@linux.alibaba.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/virtio/virtio_ring.c')
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index b82bb0b08161..51278f8bd3ab 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -829,6 +829,9 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) { struct vring_virtqueue *vq = to_vvq(_vq); + if (unlikely(vq->broken)) + return false; + virtio_mb(vq->weak_barriers); return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx); } |