This is a note to let you know that I've just added the patch titled
9p/trans_virtio: discard zero-length reply
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
9p-trans_virtio-discard-zero-length-reply.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 26d99834f89e76514076d9cd06f61e56e6a509b8 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@xxxxxxxx>
Date: Mon, 22 Jan 2018 22:02:05 +0100
Subject: 9p/trans_virtio: discard zero-length reply
From: Greg Kurz <groug@xxxxxxxx>
commit 26d99834f89e76514076d9cd06f61e56e6a509b8 upstream.
When a 9p request is successfully flushed, the server is expected to just
mark it as used without sending a 9p reply (ie, without writing data into
the buffer). In this case, virtqueue_get_buf() will return len == 0 and
we must not report a REQ_STATUS_RCVD status to the client, otherwise the
client will erroneously assume the request has not been flushed.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kurz <groug@xxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/9p/trans_virtio.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -160,7 +160,8 @@ static void req_done(struct virtqueue *v
spin_unlock_irqrestore(&chan->lock, flags);
/* Wakeup if anyone waiting for VirtIO ring space. */
wake_up(chan->vc_wq);
- p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
+ if (len)
+ p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
}
}
Patches currently in stable-queue which might be from groug@xxxxxxxx are
queue-4.9/9p-trans_virtio-discard-zero-length-reply.patch