From 5e44708f75b0f8712da715d6babb0c21089b2317 Mon Sep 17 00:00:00 2001
From: Russ Gorby <russ.gorby@intel.com>
Date: Mon, 13 Aug 2012 13:44:40 +0100
Subject: [PATCH] n_gsm: added interlocking for gsm_data_lock for certain code
 paths

There were some locking holes in the management of the MUX's
message queue for 2 code paths:
1) gsmld_write_wakeup
2) receipt of CMD_FCON flow-control message
In both cases gsm_data_kick is called w/o locking so it can collide
with other other instances of gsm_data_kick (pulling messages tx_tail)
or potentially other instances of __gsm_data_queu (adding messages to tx_head)

Changed to take the tx_lock in these 2 cases

Signed-off-by: Russ Gorby <russ.gorby@intel.com>
Tested-by: Yin, Fengwei <fengwei.yin@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Riding School <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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