Patch "[PATCH 039/135] Drivers: hv: vss: run only on supported host versions" has been added to the 4.4-stable tree

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

[PATCH 039/135] Drivers: hv: vss: run only on supported host versions

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:
0039-Drivers-hv-vss-run-only-on-supported-host-versions.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 <[email protected]> know about it.

From: Olaf Hering <[email protected]>
Date: Mon, 14 Dec 2015 16:01:42 -0800
Subject: [PATCH 039/135] Drivers: hv: vss: run only on supported host versions

[ Upstream commit ed9ba608e4851144af8c7061cbb19f751c73e998 ]

The Backup integration service on WS2012 has appearently trouble to negotiate with a guest which does not support the provided util version. Currently the VSS driver supports only version 5/0. A WS2012 offers only version 1/x and 3/x, and vmbus_prep_negotiate_resp correctly returns an empty icframe_vercnt/icmsg_vercnt. But the host ignores that and continues to send ICMSGTYPE_NEGOTIATE messages. The result are weird errors during boot and general misbehaviour.

Check the Windows version to work around the host bug, skip hv_vss_init on WS2012 and older.

---
 drivers/hv/hv_snapshot.c |    5 +++++
 1 file changed, 5 insertions(+)

@@ -331,6 +331,11 @@ static void vss_on_reset(void)
 int
 hv_vss_init(struct hv_util_service *srv)
 {
+	if (vmbus_proto_version < VERSION_WIN8_1) {
+		pr_warn("Integration service 'Backup (volume snapshot)'"
+			" not supported on this host version.\n");
+		return -ENOTSUPP;
+	}
 	recv_buffer = srv->recv_buffer;
 
 	/*

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/0036-tools-hv-report-ENOSPC-errors-in-hv_fcopy_daemon.patch queue-4.4/0035-Drivers-hv-utils-run-polling-callback-always-in-inte.patch queue-4.4/0037-Drivers-hv-util-catch-allocation-errors.patch queue-4.4/0039-Drivers-hv-vss-run-only-on-supported-host-versions.patch