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;a=summary
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@xxxxxxxxxxxxxxx> know about it.
>From d86b5672b1adb98b4cdd6fbf0224bbfb03db6e2e Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
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@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx are
queue-4.4/xen-netfront-avoid-crashing-on-resume-after-a-failure-in-talk_to_netback.patch