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From: Stefano Garzarella <sgarzare@redhat.com>
To: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	Stefan Hajnoczi <stefanha@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Michael S . Tsirkin" <mst@redhat.com>
Subject: [PATCH 3/4] vsock/virtio: fix flush of works during the .remove()
Date: Tue, 28 May 2019 12:56:22 +0200	[thread overview]
Message-ID: <20190528105623.27983-4-sgarzare@redhat.com> (raw)
In-Reply-To: <20190528105623.27983-1-sgarzare@redhat.com>

We flush all pending works before to call vdev->config->reset(vdev),
but other works can be queued before the vdev->config->del_vqs(vdev),
so we add another flush after it, to avoid use after free.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 net/vmw_vsock/virtio_transport.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e694df10ab61..ad093ce96693 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -660,6 +660,15 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	return ret;
 }
 
+static void virtio_vsock_flush_works(struct virtio_vsock *vsock)
+{
+	flush_work(&vsock->loopback_work);
+	flush_work(&vsock->rx_work);
+	flush_work(&vsock->tx_work);
+	flush_work(&vsock->event_work);
+	flush_work(&vsock->send_pkt_work);
+}
+
 static void virtio_vsock_remove(struct virtio_device *vdev)
 {
 	struct virtio_vsock *vsock = vdev->priv;
@@ -668,12 +677,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 	mutex_lock(&the_virtio_vsock_mutex);
 	the_virtio_vsock = NULL;
 
-	flush_work(&vsock->loopback_work);
-	flush_work(&vsock->rx_work);
-	flush_work(&vsock->tx_work);
-	flush_work(&vsock->event_work);
-	flush_work(&vsock->send_pkt_work);
-
 	/* Reset all connected sockets when the device disappear */
 	vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 
@@ -690,6 +693,9 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 	vsock->event_run = false;
 	mutex_unlock(&vsock->event_lock);
 
+	/* Flush all pending works */
+	virtio_vsock_flush_works(vsock);
+
 	/* Flush all device writes and interrupts, device will not use any
 	 * more buffers.
 	 */
@@ -726,6 +732,11 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 	/* Delete virtqueues and flush outstanding callbacks if any */
 	vdev->config->del_vqs(vdev);
 
+	/* Other works can be queued before 'config->del_vqs()', so we flush
+	 * all works before to free the vsock object to avoid use after free.
+	 */
+	virtio_vsock_flush_works(vsock);
+
 	kfree(vsock);
 	mutex_unlock(&the_virtio_vsock_mutex);
 }
-- 
2.20.1


  parent reply	other threads:[~2019-05-28 10:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28 10:56 [PATCH 0/4] vsock/virtio: several fixes in the .probe() and .remove() Stefano Garzarella
2019-05-28 10:56 ` [PATCH 1/4] vsock/virtio: fix locking around 'the_virtio_vsock' Stefano Garzarella
2019-05-30  4:28   ` David Miller
2019-05-30 10:27     ` Stefano Garzarella
2019-05-28 10:56 ` [PATCH 2/4] vsock/virtio: stop workers during the .remove() Stefano Garzarella
2019-05-28 10:56 ` Stefano Garzarella [this message]
2019-05-29  3:22   ` [PATCH 3/4] vsock/virtio: fix flush of works " Jason Wang
2019-05-29 10:58     ` Stefano Garzarella
2019-05-30  9:46       ` Jason Wang
2019-05-30 10:10         ` Stefano Garzarella
2019-05-30 11:59           ` Jason Wang
2019-05-31  8:18             ` Stefano Garzarella
2019-05-31  9:56               ` Jason Wang
2019-06-06  8:11                 ` Stefano Garzarella
2019-06-13  8:57                   ` Jason Wang
2019-06-27 10:26                     ` Stefano Garzarella
2019-05-28 10:56 ` [PATCH 4/4] vsock/virtio: free used buffers " Stefano Garzarella
2019-06-10 13:09 ` [PATCH 0/4] vsock/virtio: several fixes in the .probe() and .remove() Stefan Hajnoczi
2019-06-27 10:05   ` Stefano Garzarella

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