| Message ID | 20090216212815.GA21732@Chamillionaire.breakpoint.cc |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Feb 16, 2009 at 10:28:15PM +0100, Sebastian Andrzej Siewior wrote: > 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> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Lennert Buytenhek <buytenh@wantstofly.org> Date: Thu, 19 Feb 2009 02:05:29 +0100 > On Mon, Feb 16, 2009 at 10:28:15PM +0100, Sebastian Andrzej Siewior wrote: > > > 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> Also applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c index 6977abe..582b346 100644 --- a/drivers/net/mv643xx_eth.c +++ b/drivers/net/mv643xx_eth.c @@ -1173,7 +1173,7 @@ 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); @@ -1206,7 +1206,7 @@ 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); } @@ -2213,8 +2213,6 @@ 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); @@ -2226,6 +2224,7 @@ 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);
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> --- drivers/net/mv643xx_eth.c | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-)