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virtio: bugfix: add rcu_read_lock when vring_avail_idx is called

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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 <caojinhua1@huawei.com>
This commit is contained in:
Chen Qun 2022-02-10 11:16:26 +08:00 committed by yezengruan
parent c98857b3fa
commit 16b7f98db0
1 changed files with 38 additions and 0 deletions
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38
virtio-bugfix-add-rcu_read_lock-when-vring_avail_idx.patch Normal file
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@ -0,0 +1,38 @@
From 41aa66e37d04246d48b5417c57967425ecc466a0 Mon Sep 17 00:00:00 2001
From: Jinhua Cao <caojinhua1@huawei.com>
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 <caojinhua1@huawei.com>
---
hw/virtio/virtio.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 007f4c9e26..0af9684881 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2864,6 +2864,7 @@ 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) {
@@ -2874,6 +2875,7 @@ 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