patch "hv: acquire vmbus_connection.channel_mutex in vmbus_free_channels()" added to char-misc-testing

patch "hv: acquire vmbus_connection.channel_mutex in vmbus_free_channels()" added to char-misc-testing

[gregkh]

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

    hv: acquire vmbus_connection.channel_mutex in vmbus_free_channels()

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


>From abd1026da4a7700a8db370947f75cd17b6ae6f76 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Sat, 3 Dec 2016 12:34:32 -0800
Subject: hv: acquire vmbus_connection.channel_mutex in vmbus_free_channels()

"kernel BUG at drivers/hv/channel_mgmt.c:350!" is observed when hv_vmbus
module is unloaded. BUG_ON() was introduced in commit 85d9aa705184
("Drivers: hv: vmbus: add an API vmbus_hvsock_device_unregister()") as
vmbus_free_channels() codepath was apparently forgotten.

Fixes: 85d9aa705184 ("Drivers: hv: vmbus: add an API vmbus_hvsock_device_unregister()")

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hv/channel_mgmt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index e5d1b0e6c922..26b419203f16 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -389,6 +389,7 @@ void vmbus_free_channels(void)
 {
 	struct vmbus_channel *channel, *tmp;
 
+	mutex_lock(&vmbus_connection.channel_mutex);
 	list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 		listentry) {
 		/* hv_process_channel_removal() needs this */
@@ -396,6 +397,7 @@ void vmbus_free_channels(void)
 
 		vmbus_device_unregister(channel->device_obj);
 	}
+	mutex_unlock(&vmbus_connection.channel_mutex);
 }
 
 /*
-- 
2.10.2