From 8c773e04509732500d6ae245a6f4a163425a7403 Mon Sep 17 00:00:00 2001
From: Krzysztof Halasa <khc@pm.waw.pl>
Date: Wed, 14 Apr 2010 14:09:52 +0000
Subject: WAN: flush tx_queue in hdlc_ppp to prevent panic on rmmod hw_driver.


From: Krzysztof Halasa <khc@pm.waw.pl>

[ Upstream commit 31f634a63de7068c6a5dcb0d7b09b24b61a5cf88 ]

tx_queue is used as a temporary queue when not allowed to queue skb
directly to the hw device driver (which may sleep). Most paths flush
it before returning, but ppp_start() currently cannot. Make sure we
don't leave skbs pointing to a non-existent device.

Thanks to Michael Barkowski for reporting this problem.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/net/wan/hdlc_ppp.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/wan/hdlc_ppp.c
+++ b/drivers/net/wan/hdlc_ppp.c
@@ -628,9 +628,15 @@ static void ppp_stop(struct net_device *
 	ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
 }
 
+static void ppp_close(struct net_device *dev)
+{
+	ppp_tx_flush();
+}
+
 static struct hdlc_proto proto = {
 	.start		= ppp_start,
 	.stop		= ppp_stop,
+	.close		= ppp_close,
 	.type_trans	= ppp_type_trans,
 	.ioctl		= ppp_ioctl,
 	.netif_rx	= ppp_rx,