From 7b4a9547e68147291e68258db9415ef5a20fe06b Mon Sep 17 00:00:00 2001 From: Jinhua Cao Date: Thu, 10 Feb 2022 11:16:26 +0800 Subject: [PATCH] virtio: bugfix: add rcu_read_lock when vring_avail_idx is called viring_avail_idx should be called within rcu_read_lock(), or may get NULL caches in vring_get_region_caches() and trigger assert(). Signed-off-by: Jinhua Cao --- hw/virtio/virtio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 27ceab92be..ec09d515c2 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2801,6 +2801,7 @@ static void check_vring_avail_num(VirtIODevice *vdev, int index) { uint16_t nheads; + rcu_read_lock(); /* Check it isn't doing strange things with descriptor numbers. */ nheads = vring_avail_idx(&vdev->vq[index]) - vdev->vq[index].last_avail_idx; if (nheads > vdev->vq[index].vring.num) { @@ -2811,6 +2812,7 @@ static void check_vring_avail_num(VirtIODevice *vdev, int index) vring_avail_idx(&vdev->vq[index]), vdev->vq[index].last_avail_idx, nheads); } + rcu_read_unlock(); } int virtio_save(VirtIODevice *vdev, QEMUFile *f) -- 2.27.0