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FAILED: patch "[PATCH] vsock/virtio: initialize the_virtio_vsock before using VQs" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Oct 27, 2023

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Networking Stable branch virtio core VM sockets (AF_VSOCK) +1 more subsystems
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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 53b08c4985158430fd6d035fb49443bada535210
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023102739-channel-upstream-7bca@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 53b08c4985158430fd6d035fb49443bada535210 Mon Sep 17 00:00:00 2001
From: Alexandru Matei <[email protected]>
Date: Tue, 24 Oct 2023 22:17:42 +0300
Subject: [PATCH] vsock/virtio: initialize the_virtio_vsock before using VQs

Once VQs are filled with empty buffers and we kick the host, it can send connection requests. If the_virtio_vsock is not initialized before, replies are silently dropped and do not reach the host.

virtio_transport_send_pkt() can queue packets once the_virtio_vsock is set, but they won't be processed until vsock->tx_run is set to true. We queue vsock->send_pkt_work when initialization finishes to send those packets queued earlier.

Fixes 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock")
Signed-off-by Alexandru Matei <[email protected]>
Reviewed-by Stefano Garzarella <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Jakub Kicinski <[email protected]>
net/vmw_vsock/virtio_transport.c +17 -1
index e95df847176b..b80bf681327b 100644
@@ -555,6 +555,11 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
 
 	virtio_device_ready(vdev);
 
+	return 0;
+}
+
+static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
+{
 	mutex_lock(&vsock->tx_lock);
 	vsock->tx_run = true;
 	mutex_unlock(&vsock->tx_lock);

@@ -569,7 +574,16 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
 	vsock->event_run = true;
 	mutex_unlock(&vsock->event_lock);
 
-	return 0;
+	/* virtio_transport_send_pkt() can queue packets once
+	 * the_virtio_vsock is set, but they won't be processed until
+	 * vsock->tx_run is set to true. We queue vsock->send_pkt_work
+	 * when initialization finishes to send those packets queued
+	 * earlier.
+	 * We don't need to queue the other workers (rx, event) because
+	 * as long as we don't fill the queues with empty buffers, the
+	 * host can't send us any notification.
+	 */
+	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 }
 
 static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)

@@ -664,6 +678,7 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 		goto out;
 
 	rcu_assign_pointer(the_virtio_vsock, vsock);
+	virtio_vsock_vqs_start(vsock);
 
 	mutex_unlock(&the_virtio_vsock_mutex);
 

@@ -736,6 +751,7 @@ static int virtio_vsock_restore(struct virtio_device *vdev)
 		goto out;
 
 	rcu_assign_pointer(the_virtio_vsock, vsock);
+	virtio_vsock_vqs_start(vsock);
 
 out:
 	mutex_unlock(&the_virtio_vsock_mutex);