Patchwork [2/3] net: mv643xx_eth: fix orphaned statistics timer crash

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Submitter Sebastian Hesselbarth
Date Oct. 2, 2013, 10:57 a.m.
Message ID <1380711442-24735-3-git-send-email-sebastian.hesselbarth@gmail.com>
Download mbox | patch
Permalink /patch/279685/
State Accepted
Delegated to: David Miller
Headers show

Comments

Sebastian Hesselbarth - Oct. 2, 2013, 10:57 a.m.
The periodic statistics timer gets started at port _probe() time, but
is stopped on _stop() only. In a modular environment, this can cause
the timer to access already deallocated memory, if the module is unloaded
without starting the eth device. To fix this, we add the timer right
before the port is started, instead of at _probe() time.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
---
Cc: David Miller <davem@davemloft.net>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: netdev@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/net/ethernet/marvell/mv643xx_eth.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Jason - Oct. 2, 2013, 12:20 p.m.
On Wed, Oct 02, 2013 at 12:57:21PM +0200, Sebastian Hesselbarth wrote:
> The periodic statistics timer gets started at port _probe() time, but
> is stopped on _stop() only. In a modular environment, this can cause
> the timer to access already deallocated memory, if the module is unloaded
> without starting the eth device. To fix this, we add the timer right
> before the port is started, instead of at _probe() time.
> 
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
> ---
> Cc: David Miller <davem@davemloft.net>
> Cc: Lennert Buytenhek <buytenh@wantstofly.org>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: netdev@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/net/ethernet/marvell/mv643xx_eth.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Jason Cooper <jason@lakedaemon.net>

Introduced by:

  4ff3495a mv643xx_eth: enforce frequent hardware statistics polling

which also goes all the way back to v2.6.28

thx,

Jason.
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Patch

diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index 44a87e4..2364707 100644
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -2235,6 +2235,7 @@  static int mv643xx_eth_open(struct net_device *dev)
 		mp->int_mask |= INT_TX_END_0 << i;
 	}
 
+	add_timer(&mp->mib_counters_timer);
 	port_start(mp);
 
 	wrlp(mp, INT_MASK_EXT, INT_EXT_LINK_PHY | INT_EXT_TX);
@@ -2914,7 +2915,6 @@  static int mv643xx_eth_probe(struct platform_device *pdev)
 	mp->mib_counters_timer.data = (unsigned long)mp;
 	mp->mib_counters_timer.function = mib_counters_timer_wrapper;
 	mp->mib_counters_timer.expires = jiffies + 30 * HZ;
-	add_timer(&mp->mib_counters_timer);
 
 	spin_lock_init(&mp->mib_counters_lock);