[PATCH net v2 6/8] forcedeth: Fix a race during rmmod of forcedeth
From: David Decotigny <hidden>
Date: 2011-11-04 01:42:21
Also in:
lkml
Subsystem:
forcedeth gigabit ethernet driver, networking drivers, the rest · Maintainers:
Rain River, Zhu Yanjun, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Salman Qazi <redacted> The race was between del_timer_sync and nv_do_stats_poll called through nv_get_ethtool_stats. To prevent this, we have to introduce mutual exclusion between nv_get_ethtool_stats and del_timer_sync. Notice that we don't put the mutual exclusion in nv_do_stats_poll. That's because doing so would result in a deadlock, since it is a timer callback and hence already waited for by timer deletion. Signed-off-by: David Decotigny <redacted> --- drivers/net/ethernet/nvidia/forcedeth.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 0af12a8..7996782 100644
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c@@ -3937,6 +3937,10 @@ static void nv_poll_controller(struct net_device *dev) } #endif +/* No locking is needed as long as this is in the timer + * callback. However, any other callers must call this + * function with np->lock held. + */ static void nv_do_stats_poll(unsigned long data) { struct net_device *dev = (struct net_device *) data;
@@ -4589,12 +4593,17 @@ static int nv_get_sset_count(struct net_device *dev, int sset) static void nv_get_ethtool_stats(struct net_device *dev, struct ethtool_stats *estats, u64 *buffer) { + unsigned long flags; struct fe_priv *np = netdev_priv(dev); + spin_lock_irqsave(&np->lock, flags); + /* update stats */ nv_do_stats_poll((unsigned long)dev); memcpy(buffer, &np->estats, nv_get_sset_count(dev, ETH_SS_STATS)*sizeof(u64)); + + spin_unlock_irqrestore(&np->lock, flags); } static int nv_link_test(struct net_device *dev)
@@ -5189,13 +5198,13 @@ static int nv_close(struct net_device *dev) spin_lock_irq(&np->lock); np->in_shutdown = 1; + del_timer_sync(&np->stats_poll); spin_unlock_irq(&np->lock); nv_napi_disable(dev); synchronize_irq(np->pci_dev->irq); del_timer_sync(&np->oom_kick); del_timer_sync(&np->nic_poll); - del_timer_sync(&np->stats_poll); netif_stop_queue(dev); spin_lock_irq(&np->lock);
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1.7.3.1