From: Stefano Garzarella <sgarzare@redhat.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Lee Jones <lee.jones@linaro.org>, jasowang@redhat.com, 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: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Date: Wed, 2 Mar 2022 15:11:21 +0100 [thread overview] Message-ID: <20220302141121.sohhkhtiiaydlv47@sgarzare-redhat> (raw) In-Reply-To: <20220302083413-mutt-send-email-mst@kernel.org> On Wed, Mar 02, 2022 at 08:35:08AM -0500, Michael S. Tsirkin wrote: >On Wed, Mar 02, 2022 at 10:34:46AM +0100, Stefano Garzarella wrote: >> On Wed, Mar 02, 2022 at 07:54:21AM +0000, Lee Jones wrote: >> > vhost_vsock_handle_tx_kick() already holds the mutex during its call >> > to vhost_get_vq_desc(). All we have to do is take the same lock >> > during virtqueue clean-up and we mitigate the reported issues. >> > >> > Link: https://syzkaller.appspot.com/bug?extid=279432d30d825e63ba00 >> >> This issue is similar to [1] that should be already fixed upstream by [2]. >> >> However I think this patch would have prevented some issues, because >> vhost_vq_reset() sets vq->private to NULL, preventing the worker from >> running. >> >> Anyway I think that when we enter in vhost_dev_cleanup() the worker should >> be already stopped, so it shouldn't be necessary to take the mutex. But in >> order to prevent future issues maybe it's better to take them, so: >> >> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> >> >> [1] >> https://syzkaller.appspot.com/bug?id=993d8b5e64393ed9e6a70f9ae4de0119c605a822 >> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a58da53ffd70294ebea8ecd0eb45fd0d74add9f9 > > >Right. I want to queue this but I would like to get a warning >so we can detect issues like [2] before they cause more issues. I agree, what about moving the warning that we already have higher up, right at the beginning of the function? I mean something like this: diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 59edb5a1ffe2..1721ff3f18c0 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -692,6 +692,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev) { int i; + WARN_ON(!llist_empty(&dev->work_list)); + for (i = 0; i < dev->nvqs; ++i) { if (dev->vqs[i]->error_ctx) eventfd_ctx_put(dev->vqs[i]->error_ctx); @@ -712,7 +714,6 @@ void vhost_dev_cleanup(struct vhost_dev *dev) dev->iotlb = NULL; vhost_clear_msg(dev); wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); - WARN_ON(!llist_empty(&dev->work_list)); if (dev->worker) { kthread_stop(dev->worker); dev->worker = NULL; And maybe we can also check vq->private and warn in the loop, because the work_list may be empty if the device is doing nothing. Thanks, Stefano
WARNING: multiple messages have this Message-ID (diff)
From: Stefano Garzarella <sgarzare@redhat.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com, kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, virtualization@lists.linux-foundation.org, Lee Jones <lee.jones@linaro.org> Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Date: Wed, 2 Mar 2022 15:11:21 +0100 [thread overview] Message-ID: <20220302141121.sohhkhtiiaydlv47@sgarzare-redhat> (raw) In-Reply-To: <20220302083413-mutt-send-email-mst@kernel.org> On Wed, Mar 02, 2022 at 08:35:08AM -0500, Michael S. Tsirkin wrote: >On Wed, Mar 02, 2022 at 10:34:46AM +0100, Stefano Garzarella wrote: >> On Wed, Mar 02, 2022 at 07:54:21AM +0000, Lee Jones wrote: >> > vhost_vsock_handle_tx_kick() already holds the mutex during its call >> > to vhost_get_vq_desc(). All we have to do is take the same lock >> > during virtqueue clean-up and we mitigate the reported issues. >> > >> > Link: https://syzkaller.appspot.com/bug?extid=279432d30d825e63ba00 >> >> This issue is similar to [1] that should be already fixed upstream by [2]. >> >> However I think this patch would have prevented some issues, because >> vhost_vq_reset() sets vq->private to NULL, preventing the worker from >> running. >> >> Anyway I think that when we enter in vhost_dev_cleanup() the worker should >> be already stopped, so it shouldn't be necessary to take the mutex. But in >> order to prevent future issues maybe it's better to take them, so: >> >> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> >> >> [1] >> https://syzkaller.appspot.com/bug?id=993d8b5e64393ed9e6a70f9ae4de0119c605a822 >> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a58da53ffd70294ebea8ecd0eb45fd0d74add9f9 > > >Right. I want to queue this but I would like to get a warning >so we can detect issues like [2] before they cause more issues. I agree, what about moving the warning that we already have higher up, right at the beginning of the function? I mean something like this: diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 59edb5a1ffe2..1721ff3f18c0 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -692,6 +692,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev) { int i; + WARN_ON(!llist_empty(&dev->work_list)); + for (i = 0; i < dev->nvqs; ++i) { if (dev->vqs[i]->error_ctx) eventfd_ctx_put(dev->vqs[i]->error_ctx); @@ -712,7 +714,6 @@ void vhost_dev_cleanup(struct vhost_dev *dev) dev->iotlb = NULL; vhost_clear_msg(dev); wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); - WARN_ON(!llist_empty(&dev->work_list)); if (dev->worker) { kthread_stop(dev->worker); dev->worker = NULL; And maybe we can also check vq->private and warn in the loop, because the work_list may be empty if the device is doing nothing. Thanks, Stefano _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2022-03-02 14:11 UTC|newest] Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-02 7:54 [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Lee Jones 2022-03-02 7:54 ` Lee Jones 2022-03-02 9:34 ` Stefano Garzarella 2022-03-02 9:34 ` Stefano Garzarella 2022-03-02 10:07 ` Lee Jones 2022-03-02 10:07 ` Lee Jones 2022-03-02 13:35 ` Michael S. Tsirkin 2022-03-02 13:35 ` Michael S. Tsirkin 2022-03-02 14:11 ` Stefano Garzarella [this message] 2022-03-02 14:11 ` Stefano Garzarella 2022-03-02 14:50 ` Michael S. Tsirkin 2022-03-02 14:50 ` Michael S. Tsirkin 2022-03-02 15:36 ` Stefano Garzarella 2022-03-02 15:36 ` Stefano Garzarella 2022-03-04 16:46 ` Michael S. Tsirkin 2022-03-04 16:46 ` Michael S. Tsirkin 2022-03-02 13:30 ` Michael S. Tsirkin 2022-03-02 13:30 ` Michael S. Tsirkin 2022-03-02 13:56 ` Lee Jones 2022-03-02 13:56 ` Lee Jones 2022-03-02 14:51 ` Michael S. Tsirkin 2022-03-02 14:51 ` Michael S. Tsirkin 2022-03-02 14:57 ` Lee Jones 2022-03-02 14:57 ` Lee Jones 2022-03-02 16:28 ` Stefano Garzarella 2022-03-02 16:28 ` Stefano Garzarella 2022-03-02 16:30 ` Michael S. Tsirkin 2022-03-02 16:30 ` Michael S. Tsirkin 2022-03-02 16:49 ` Lee Jones 2022-03-02 16:49 ` Lee Jones 2022-03-02 17:10 ` Stefano Garzarella 2022-03-02 17:10 ` Stefano Garzarella 2022-03-03 14:17 ` Lee Jones 2022-03-03 14:17 ` Lee Jones 2022-03-04 5:00 ` Michael S. Tsirkin 2022-03-04 5:00 ` Michael S. Tsirkin 2022-03-04 15:22 ` Lee Jones 2022-03-04 15:22 ` Lee Jones 2022-03-04 16:48 ` Michael S. Tsirkin 2022-03-04 16:48 ` Michael S. Tsirkin 2022-03-04 16:56 ` Lee Jones 2022-03-04 16:56 ` Lee Jones 2022-03-07 19:17 Lee Jones 2022-03-07 19:17 ` Lee Jones 2022-03-07 19:33 ` Greg KH 2022-03-07 19:33 ` Greg KH 2022-03-07 22:39 ` Michael S. Tsirkin 2022-03-07 22:39 ` Michael S. Tsirkin 2022-03-08 8:10 ` Lee Jones 2022-03-08 8:10 ` Lee Jones 2022-03-08 8:11 ` Lee Jones 2022-03-08 8:11 ` Lee Jones 2022-03-08 8:57 ` Greg KH 2022-03-08 8:57 ` Greg KH 2022-03-08 9:15 ` Lee Jones 2022-03-08 9:15 ` Lee Jones 2022-03-08 9:57 ` Greg KH 2022-03-08 9:57 ` Greg KH 2022-03-08 10:08 ` Lee Jones 2022-03-08 10:08 ` Lee Jones 2022-03-08 10:55 ` Michael S. Tsirkin 2022-03-08 10:55 ` Michael S. Tsirkin 2022-03-08 11:45 ` Greg KH 2022-03-08 11:45 ` Greg KH 2022-03-08 12:27 ` Michael S. Tsirkin 2022-03-08 12:27 ` Michael S. Tsirkin 2022-03-08 13:17 ` Lee Jones 2022-03-08 13:17 ` Lee Jones 2022-03-08 17:17 ` Michael S. Tsirkin 2022-03-08 17:17 ` Michael S. Tsirkin 2022-03-08 11:05 ` Michael S. Tsirkin 2022-03-08 11:05 ` Michael S. Tsirkin 2022-03-09 18:52 ` Leon Romanovsky 2022-03-09 18:52 ` Leon Romanovsky 2022-03-07 22:37 ` Michael S. Tsirkin 2022-03-07 22:37 ` Michael S. Tsirkin 2022-03-08 8:01 ` Lee Jones 2022-03-08 8:01 ` Lee Jones 2022-03-08 11:07 ` Michael S. Tsirkin 2022-03-08 11:07 ` Michael S. Tsirkin 2022-03-08 6:15 ` Jason Wang 2022-03-08 6:15 ` Jason Wang 2022-03-08 8:08 ` Lee Jones 2022-03-08 8:08 ` Lee Jones 2022-03-08 11:06 ` Michael S. Tsirkin 2022-03-08 11:06 ` Michael S. Tsirkin 2022-03-14 8:43 Lee Jones 2022-03-14 8:43 ` Lee Jones 2022-03-14 8:56 ` Greg KH 2022-03-14 8:56 ` Greg KH 2022-03-14 11:49 ` Michael S. Tsirkin 2022-03-14 11:49 ` Michael S. Tsirkin 2022-03-14 12:47 ` Lee Jones 2022-03-14 12:47 ` Lee Jones
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