linux-stable/drivers/virtio
Mao Wenan 1f49e8cefa virtio_ring: Avoid loop when vq is broken in virtqueue_poll
[ Upstream commit 481a0d7422 ]

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>
2020-08-26 10:29:57 +02:00
..
Kconfig
Makefile
virtio.c
virtio_balloon.c virtio_balloon: prevent pfn array overflow 2020-02-28 16:36:09 +01:00
virtio_input.c
virtio_mmio.c
virtio_pci_common.c virtio_pci: fix a NULL pointer reference in vp_del_vqs 2019-05-10 17:53:11 +02:00
virtio_pci_common.h
virtio_pci_legacy.c
virtio_pci_modern.c
virtio_ring.c virtio_ring: Avoid loop when vq is broken in virtqueue_poll 2020-08-26 10:29:57 +02:00