From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matti Linnanvuori Subject: [Bug 9750] dev: avoid a race that triggers assertion failure Date: Tue, 22 Jan 2008 03:27:00 -0800 (PST) Message-ID: <265315.88937.qm@web52009.mail.re2.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: bugme-daemon@kernel-bugs.osdl.org To: netdev@vger.kernel.org, jgarzik@pobox.com Return-path: Received: from web52009.mail.re2.yahoo.com ([206.190.48.58]:26729 "HELO web52009.mail.re2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750823AbYAVL1D (ORCPT ); Tue, 22 Jan 2008 06:27:03 -0500 Sender: netdev-owner@vger.kernel.org List-ID: From: Matti Linnanvuori There is a race in Linux kernel file net/core/dev.c, function dev_close. The function calls function dev_deactivate, which calls function dev_watchdog_down that deletes the watchdog timer. However, after that, a driver can call netif_carrier_ok, which calls function __netdev_watchdog_up that can add the watchdog timer again. Function unregister_netdevice calls function dev_shutdown that traps the bug !timer_pending(&dev->watchdog_timer). Signed-off-by: Matti Linnanvuori --- --- linux-2.6.23.8/net/core/dev.c 2007-11-16 20:14:27.000000000 +0200 +++ linux-2.6.23.15/net/core/dev.c 2008-01-22 13:16:12.347125794 +0200 @@ -1013,8 +1013,6 @@ int dev_close(struct net_device *dev) */ raw_notifier_call_chain(&netdev_chain, NETDEV_GOING_DOWN, dev); - dev_deactivate(dev); - clear_bit(__LINK_STATE_START, &dev->state); /* Synchronize to scheduled poll. We cannot touch poll list, @@ -1029,6 +1027,8 @@ int dev_close(struct net_device *dev) msleep(1); } + dev_deactivate(dev); + /* * Call the device specific close. This cannot fail. * Only if device is UP ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping