From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754320Ab1KDBmV (ORCPT ); Thu, 3 Nov 2011 21:42:21 -0400 Received: from smtp-out.google.com ([74.125.121.67]:52648 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754248Ab1KDBmQ (ORCPT ); Thu, 3 Nov 2011 21:42:16 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to: references:in-reply-to:references:organization:x-system-of-record; b=HhbXxHFm+y5701U6uDNjSTnOx9rd9saXAvILcbziVaLkOgBySlwfvuQVCRtZxPpzg ewZs/zat2ZS1Lku7aHTVw== From: David Decotigny To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "David S. Miller" , Ian Campbell , Eric Dumazet , Jeff Kirsher , Jiri Pirko , Joe Perches , Szymon Janc , Salman Qazi , David Decotigny Subject: [PATCH net v2 6/8] forcedeth: Fix a race during rmmod of forcedeth Date: Thu, 3 Nov 2011 18:41:21 -0700 Message-Id: <267015997eb594f2fd859acd572aa20dfc3e3e63.1320369398.git.david.decotigny@google.com> X-Mailer: git-send-email 1.7.3.1 In-Reply-To: References: In-Reply-To: References: Organization: Google, Inc. X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Salman Qazi 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 --- 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); -- 1.7.3.1