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authorMao Wenan <wenan.mao@linux.alibaba.com>2020-08-02 10:44:09 +0300
committerMichael S. Tsirkin <mst@redhat.com>2020-08-05 18:08:41 +0300
commit481a0d7422db26fb63e2d64f0652667a5c6d0f3e (patch)
tree6e49aa0f8afb2fa31add1737fb04e899f81c1186 /drivers/virtio
parent64ffa39dc860fb9772225c694353f73eca5801c6 (diff)
downloadlinux-481a0d7422db26fb63e2d64f0652667a5c6d0f3e.tar.xz
virtio_ring: Avoid loop when vq is broken in virtqueue_poll
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>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_ring.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 34253cb69cb8..7d4bc9eb7fc5 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1960,6 +1960,9 @@ 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 vq->packed_ring ? virtqueue_poll_packed(_vq, last_used_idx) :
virtqueue_poll_split(_vq, last_used_idx);