This is a note to let you know that I've just added the patch titled

xen-netfront: avoid crashing on resume after a failure in talk_to_netback()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: xen-netfront-avoid-crashing-on-resume-after-a-failure-in-talk_to_netback.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From d86b5672b1adb98b4cdd6fbf0224bbfb03db6e2e Mon Sep 17 00:00:00 2001

From: Vitaly Kuznetsov vkuznets@redhat.com Date: Thu, 11 May 2017 13:58:06 +0200 Subject: xen-netfront: avoid crashing on resume after a failure in talk_to_netback()

From: Vitaly Kuznetsov vkuznets@redhat.com

commit d86b5672b1adb98b4cdd6fbf0224bbfb03db6e2e upstream.

Unavoidable crashes in netfront_resume() and netback_changed() after a previous fail in talk_to_netback() (e.g. when we fail to read MAC from xenstore) were discovered. The failure path in talk_to_netback() does unregister/free for netdev but we don't reset drvdata and we try accessing it after resume.

Fix the bug by removing the whole xen device completely with device_unregister(), this guarantees we won't have any calls into netfront after a failure.

Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Cc: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/net/xen-netfront.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1944,8 +1944,7 @@ abort_transaction_no_dev_fatal: xennet_disconnect_backend(info); xennet_destroy_queues(info); out: - unregister_netdev(info->netdev); - xennet_free_netdev(info->netdev); + device_unregister(&dev->dev); return err; }

Patches currently in stable-queue which might be from vkuznets@redhat.com are

queue-4.4/xen-netfront-avoid-crashing-on-resume-after-a-failure-in-talk_to_netback.patch