* [PATCH net] vhost: synchronize IOTLB message with dev cleanup
@ 2018-05-22 11:58 Jason Wang
2018-05-24 19:35 ` David Miller
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Jason Wang @ 2018-05-22 11:58 UTC (permalink / raw)
To: mst, jasowang; +Cc: netdev, linux-kernel, kvm, virtualization
DaeRyong Jeong reports a race between vhost_dev_cleanup() and
vhost_process_iotlb_msg():
Thread interleaving:
CPU0 (vhost_process_iotlb_msg) CPU1 (vhost_dev_cleanup)
(In the case of both VHOST_IOTLB_UPDATE and
VHOST_IOTLB_INVALIDATE)
===== =====
vhost_umem_clean(dev->iotlb);
if (!dev->iotlb) {
ret = -EFAULT;
break;
}
dev->iotlb = NULL;
The reason is we don't synchronize between them, fixing by protecting
vhost_process_iotlb_msg() with dev mutex.
Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index f3bd8e9..f0be5f3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -981,6 +981,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
{
int ret = 0;
+ mutex_lock(&dev->mutex);
vhost_dev_lock_vqs(dev);
switch (msg->type) {
case VHOST_IOTLB_UPDATE:
@@ -1016,6 +1017,8 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
}
vhost_dev_unlock_vqs(dev);
+ mutex_unlock(&dev->mutex);
+
return ret;
}
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] vhost: synchronize IOTLB message with dev cleanup
2018-05-22 11:58 [PATCH net] vhost: synchronize IOTLB message with dev cleanup Jason Wang
@ 2018-05-24 19:35 ` David Miller
2018-05-25 0:33 ` Michael S. Tsirkin
2018-05-25 2:10 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2018-05-24 19:35 UTC (permalink / raw)
To: jasowang; +Cc: mst, kvm, virtualization, netdev, linux-kernel
From: Jason Wang <jasowang@redhat.com>
Date: Tue, 22 May 2018 19:58:57 +0800
> DaeRyong Jeong reports a race between vhost_dev_cleanup() and
> vhost_process_iotlb_msg():
>
> Thread interleaving:
> CPU0 (vhost_process_iotlb_msg) CPU1 (vhost_dev_cleanup)
> (In the case of both VHOST_IOTLB_UPDATE and
> VHOST_IOTLB_INVALIDATE)
> ===== =====
> vhost_umem_clean(dev->iotlb);
> if (!dev->iotlb) {
> ret = -EFAULT;
> break;
> }
> dev->iotlb = NULL;
>
> The reason is we don't synchronize between them, fixing by protecting
> vhost_process_iotlb_msg() with dev mutex.
>
> Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Michael, please review.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] vhost: synchronize IOTLB message with dev cleanup
2018-05-22 11:58 [PATCH net] vhost: synchronize IOTLB message with dev cleanup Jason Wang
2018-05-24 19:35 ` David Miller
@ 2018-05-25 0:33 ` Michael S. Tsirkin
2018-05-25 2:10 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2018-05-25 0:33 UTC (permalink / raw)
To: Jason Wang; +Cc: kvm, virtualization, netdev, linux-kernel
On Tue, May 22, 2018 at 07:58:57PM +0800, Jason Wang wrote:
> DaeRyong Jeong reports a race between vhost_dev_cleanup() and
> vhost_process_iotlb_msg():
>
> Thread interleaving:
> CPU0 (vhost_process_iotlb_msg) CPU1 (vhost_dev_cleanup)
> (In the case of both VHOST_IOTLB_UPDATE and
> VHOST_IOTLB_INVALIDATE)
> ===== =====
> vhost_umem_clean(dev->iotlb);
> if (!dev->iotlb) {
> ret = -EFAULT;
> break;
> }
> dev->iotlb = NULL;
>
> The reason is we don't synchronize between them, fixing by protecting
> vhost_process_iotlb_msg() with dev mutex.
>
> Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
We should think of a way to have a per-vq lock here, but for now:
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/vhost.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f3bd8e9..f0be5f3 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -981,6 +981,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
> {
> int ret = 0;
>
> + mutex_lock(&dev->mutex);
> vhost_dev_lock_vqs(dev);
> switch (msg->type) {
> case VHOST_IOTLB_UPDATE:
> @@ -1016,6 +1017,8 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
> }
>
> vhost_dev_unlock_vqs(dev);
> + mutex_unlock(&dev->mutex);
> +
> return ret;
> }
> ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> --
> 2.7.4
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] vhost: synchronize IOTLB message with dev cleanup
2018-05-22 11:58 [PATCH net] vhost: synchronize IOTLB message with dev cleanup Jason Wang
2018-05-24 19:35 ` David Miller
2018-05-25 0:33 ` Michael S. Tsirkin
@ 2018-05-25 2:10 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2018-05-25 2:10 UTC (permalink / raw)
To: jasowang; +Cc: mst, kvm, virtualization, netdev, linux-kernel
From: Jason Wang <jasowang@redhat.com>
Date: Tue, 22 May 2018 19:58:57 +0800
> DaeRyong Jeong reports a race between vhost_dev_cleanup() and
> vhost_process_iotlb_msg():
>
> Thread interleaving:
> CPU0 (vhost_process_iotlb_msg) CPU1 (vhost_dev_cleanup)
> (In the case of both VHOST_IOTLB_UPDATE and
> VHOST_IOTLB_INVALIDATE)
> ===== =====
> vhost_umem_clean(dev->iotlb);
> if (!dev->iotlb) {
> ret = -EFAULT;
> break;
> }
> dev->iotlb = NULL;
>
> The reason is we don't synchronize between them, fixing by protecting
> vhost_process_iotlb_msg() with dev mutex.
>
> Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Applied and queued up for -stable.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-05-25 2:10 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-22 11:58 [PATCH net] vhost: synchronize IOTLB message with dev cleanup Jason Wang
2018-05-24 19:35 ` David Miller
2018-05-25 0:33 ` Michael S. Tsirkin
2018-05-25 2:10 ` David Miller
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).