From: Lee Jones <lee.jones@linaro.org>
To: lee.jones@linaro.org, mst@redhat.com, jasowang@redhat.com
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, stable@vger.kernel.org,
syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com
Subject: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use
Date: Mon, 7 Mar 2022 19:17:57 +0000 [thread overview]
Message-ID: <20220307191757.3177139-1-lee.jones@linaro.org> (raw)
vhost_vsock_handle_tx_kick() already holds the mutex during its call
to vhost_get_vq_desc(). All we have to do here is take the same lock
during virtqueue clean-up and we mitigate the reported issues.
Also WARN() as a precautionary measure. The purpose of this is to
capture possible future race conditions which may pop up over time.
Link: https://syzkaller.appspot.com/bug?extid=279432d30d825e63ba00
Cc: <stable@vger.kernel.org>
Reported-by: syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/vhost/vhost.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 59edb5a1ffe28..ef7e371e3e649 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -693,6 +693,15 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
int i;
for (i = 0; i < dev->nvqs; ++i) {
+ /* No workers should run here by design. However, races have
+ * previously occurred where drivers have been unable to flush
+ * all work properly prior to clean-up. Without a successful
+ * flush the guest will malfunction, but avoiding host memory
+ * corruption in those cases does seem preferable.
+ */
+ WARN_ON(mutex_is_locked(&dev->vqs[i]->mutex));
+
+ mutex_lock(&dev->vqs[i]->mutex);
if (dev->vqs[i]->error_ctx)
eventfd_ctx_put(dev->vqs[i]->error_ctx);
if (dev->vqs[i]->kick)
@@ -700,6 +709,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
if (dev->vqs[i]->call_ctx.ctx)
eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
vhost_vq_reset(dev, dev->vqs[i]);
+ mutex_unlock(&dev->vqs[i]->mutex);
}
vhost_dev_free_iovecs(dev);
if (dev->log_ctx)
--
2.35.1.616.g0bdcbb4464-goog
next reply other threads:[~2022-03-07 19:18 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 19:17 Lee Jones [this message]
2022-03-07 19:33 ` [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Greg KH
2022-03-07 22:39 ` Michael S. Tsirkin
2022-03-08 8:10 ` Lee Jones
2022-03-08 8:11 ` Lee Jones
2022-03-08 8:57 ` Greg KH
2022-03-08 9:15 ` Lee Jones
2022-03-08 9:57 ` Greg KH
2022-03-08 10:08 ` Lee Jones
2022-03-08 10:55 ` Michael S. Tsirkin
2022-03-08 11:45 ` Greg KH
2022-03-08 12:27 ` Michael S. Tsirkin
2022-03-08 13:17 ` Lee Jones
2022-03-08 17:17 ` Michael S. Tsirkin
2022-03-08 11:05 ` Michael S. Tsirkin
2022-03-09 18:52 ` Leon Romanovsky
2022-03-07 22:37 ` Michael S. Tsirkin
2022-03-08 8:01 ` Lee Jones
2022-03-08 11:07 ` Michael S. Tsirkin
2022-03-08 6:15 ` Jason Wang
2022-03-08 8:08 ` Lee Jones
2022-03-08 11:06 ` Michael S. Tsirkin
-- strict thread matches above, loose matches on Subject: below --
2022-03-14 8:43 Lee Jones
2022-03-14 8:56 ` Greg KH
2022-03-14 11:49 ` Michael S. Tsirkin
2022-03-14 12:47 ` Lee Jones
2022-03-02 7:54 Lee Jones
2022-03-02 9:34 ` Stefano Garzarella
2022-03-02 10:07 ` Lee Jones
2022-03-02 13:35 ` Michael S. Tsirkin
2022-03-02 14:11 ` Stefano Garzarella
2022-03-02 14:50 ` Michael S. Tsirkin
2022-03-02 15:36 ` Stefano Garzarella
2022-03-04 16:46 ` Michael S. Tsirkin
2022-03-02 13:30 ` Michael S. Tsirkin
2022-03-02 13:56 ` Lee Jones
2022-03-02 14:51 ` Michael S. Tsirkin
2022-03-02 14:57 ` Lee Jones
2022-03-02 16:28 ` Stefano Garzarella
2022-03-02 16:30 ` Michael S. Tsirkin
2022-03-02 16:49 ` Lee Jones
2022-03-02 17:10 ` Stefano Garzarella
2022-03-03 14:17 ` Lee Jones
2022-03-04 5:00 ` Michael S. Tsirkin
2022-03-04 15:22 ` Lee Jones
2022-03-04 16:48 ` Michael S. Tsirkin
2022-03-04 16:56 ` Lee Jones
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