From 57e8f26a10ac4af488292199bb0435555f6723f3 Mon Sep 17 00:00:00 2001
From: Sebastian Siewior <sebastian@breakpoint.cc>
Date: Mon, 16 Feb 2009 11:28:15 +0000
Subject: [PATCH] net/mv643xx: don't disable the mib timer too early and lock
 properly

mib_counters_update() also restarts the timer.
So the timer is dequeued, the stats are read and then the timer is
enqueued again. This is "okay" unless someone unloads the module.
The locking here is also broken:
mib_counters_update() grabs just a simple spinlock. The only thing the
lock is good for is to protect the timer func against other callers
namely mv643xx_eth_stop() && mv643xx_eth_get_ethtool_stats(). That means
if the spinlock is taken via the ethtool path and than the timer kicks
in then the box will lock up.

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Acked-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/mv643xx_eth.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index b6ab46942b98..13f11f402a99 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -1175,7 +1175,7 @@ static void mib_counters_update(struct mv643xx_eth_private *mp)
 {
 	struct mib_counters *p = &mp->mib_counters;
 
-	spin_lock(&mp->mib_counters_lock);
+	spin_lock_bh(&mp->mib_counters_lock);
 	p->good_octets_received += mib_read(mp, 0x00);
 	p->good_octets_received += (u64)mib_read(mp, 0x04) << 32;
 	p->bad_octets_received += mib_read(mp, 0x08);
@@ -1208,7 +1208,7 @@ static void mib_counters_update(struct mv643xx_eth_private *mp)
 	p->bad_crc_event += mib_read(mp, 0x74);
 	p->collision += mib_read(mp, 0x78);
 	p->late_collision += mib_read(mp, 0x7c);
-	spin_unlock(&mp->mib_counters_lock);
+	spin_unlock_bh(&mp->mib_counters_lock);
 
 	mod_timer(&mp->mib_counters_timer, jiffies + 30 * HZ);
 }
@@ -2216,8 +2216,6 @@ static int mv643xx_eth_stop(struct net_device *dev)
 	wrlp(mp, INT_MASK, 0x00000000);
 	rdlp(mp, INT_MASK);
 
-	del_timer_sync(&mp->mib_counters_timer);
-
 	napi_disable(&mp->napi);
 
 	del_timer_sync(&mp->rx_oom);
@@ -2229,6 +2227,7 @@ static int mv643xx_eth_stop(struct net_device *dev)
 	port_reset(mp);
 	mv643xx_eth_get_stats(dev);
 	mib_counters_update(mp);
+	del_timer_sync(&mp->mib_counters_timer);
 
 	skb_queue_purge(&mp->rx_recycle);
 
-- 
2.34.1