Patch "Drivers: hv: vmbus: Prevent sending data on a rescinded channel" has been added to the 4.10-stable tree

[<gregkh@linuxfoundation.org>]

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

    Drivers: hv: vmbus: Prevent sending data on a rescinded channel

to the 4.10-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:
     drivers-hv-vmbus-prevent-sending-data-on-a-rescinded-channel.patch
and it can be found in the queue-4.10 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 e7e97dd8b77ee7366f2f8c70a033bf5fa05ec2e0 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: Wed, 7 Dec 2016 01:16:28 -0800
Subject: Drivers: hv: vmbus: Prevent sending data on a rescinded channel

From: K. Y. Srinivasan <kys@microsoft.com>

commit e7e97dd8b77ee7366f2f8c70a033bf5fa05ec2e0 upstream.

After the channel is rescinded, the host does not read from the rescinded channel.
Fail writes to a channel that has already been rescinded. If we permit writes on a
rescinded channel, since the host will not respond we will have situations where
we will be unable to unload vmbus drivers that cannot have any outstanding requests
to the host at the point they are unoaded.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hv/ring_buffer.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -298,6 +298,9 @@ int hv_ringbuffer_write(struct vmbus_cha
 	unsigned long flags = 0;
 	struct hv_ring_buffer_info *outring_info = &channel->outbound;
 
+	if (channel->rescind)
+		return -ENODEV;
+
 	for (i = 0; i < kv_count; i++)
 		totalbytes_towrite += kv_list[i].iov_len;
 
@@ -350,6 +353,10 @@ int hv_ringbuffer_write(struct vmbus_cha
 		spin_unlock_irqrestore(&outring_info->ring_lock, flags);
 
 	hv_signal_on_write(old_write, channel, kick_q);
+
+	if (channel->rescind)
+		return -ENODEV;
+
 	return 0;
 }
 


Patches currently in stable-queue which might be from kys@microsoft.com are

queue-4.10/hv-init-percpu_list-in-hv_synic_alloc.patch
queue-4.10/drivers-hv-vmbus-prevent-sending-data-on-a-rescinded-channel.patch
queue-4.10/drivers-hv-util-backup-fix-a-rescind-processing-issue.patch
queue-4.10/drivers-hv-util-fcopy-fix-a-rescind-processing-issue.patch
queue-4.10/pci-hv-fix-wslot_to_devfn-to-fix-warnings-on-device-removal.patch
queue-4.10/scsi-storvsc-use-tagged-srb-requests-if-supported-by-the-device.patch
queue-4.10/drivers-hv-vmbus-raise-retry-wait-limits-in-vmbus_post_msg.patch
queue-4.10/drivers-hv-util-kvp-fix-a-rescind-processing-issue.patch
queue-4.10/hv-allocate-synic-pages-for-all-present-cpus.patch
queue-4.10/hv-don-t-reset-hv_context.tsc_page-on-crash.patch
queue-4.10/scsi-storvsc-properly-set-residual-data-length-on-errors.patch
queue-4.10/scsi-storvsc-properly-handle-srb_error-when-sense-message-is-present.patch
queue-4.10/drivers-hv-vmbus-fix-a-rescind-handling-bug.patch