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Commit 33c150c2 authored by Dexuan Cui's avatar Dexuan Cui Committed by Greg Kroah-Hartman
Browse files

vmbus: don't acquire the mutex in vmbus_hvsock_device_unregister() 



Due to commit 54a66265 ("Drivers: hv: vmbus: Fix rescind handling"),
we need this patch to resolve the below deadlock:

after we get the mutex in vmbus_hvsock_device_unregister() and call
vmbus_device_unregister() -> device_unregister() -> ... -> device_release()
-> vmbus_device_release(), we'll get a deadlock, because
vmbus_device_release() tries to get the same mutex.

Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org (4.13 and above)
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 24600840

drivers/hv/channel_mgmt.c

+0 −4
Original line number Diff line number Diff line
@@ -936,14 +936,10 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr) 


void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)

{

	mutex_lock(&vmbus_connection.channel_mutex);



	BUG_ON(!is_hvsock_channel(channel));



	channel->rescind = true;

	vmbus_device_unregister(channel->device_obj);



	mutex_unlock(&vmbus_connection.channel_mutex);

}

EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);