commit 9a035a40f7f3f6708b79224b86c5777a3334f7ea

Author: Jan Beulich <JBeulich@suse.com>

Date:   Mon Aug 15 09:02:38 2016 -0600

    xenbus: don't look up transaction IDs for ordinary writes

    This should really only be done for XS_TRANSACTION_END messages, or

    else at least some of the xenstore-* tools don't work anymore.

    Fixes: 0beef634b8 ("xenbus: don't BUG() on user mode induced condition")

    Reported-by: Richard Schütz <rschuetz@uni-koblenz.de>

    Cc: <stable@vger.kernel.org>

    Signed-off-by: Jan Beulich <jbeulich@suse.com>

    Tested-by: Richard Schütz <rschuetz@uni-koblenz.de>

    Signed-off-by: David Vrabel <david.vrabel@citrix.com>

diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c

index 7487971..c1010f01 100644

--- a/drivers/xen/xenbus/xenbus_dev_frontend.c

+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c

@@ -316,7 +316,7 @@ static int xenbus_write_transaction(unsigned msg_type,

 			rc = -ENOMEM;

 			goto out;

 		}

-	} else {

+	} else if (msg_type == XS_TRANSACTION_END) {

 		list_for_each_entry(trans, &u->transactions, list)

 			if (trans->handle.id == u->u.msg.tx_id)

 				break;