Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757497AbXJCPOS (ORCPT ); Wed, 3 Oct 2007 11:14:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753559AbXJCPOL (ORCPT ); Wed, 3 Oct 2007 11:14:11 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:44298 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752735AbXJCPOK (ORCPT ); Wed, 3 Oct 2007 11:14:10 -0400 Date: Wed, 3 Oct 2007 08:12:13 -0700 From: Arjan van de Ven To: Al Viro Cc: Ingo Molnar , Linus Torvalds , Linux Kernel Mailing List , Greg KH , Peter Zijlstra Subject: Re: [bug] crash when reading /proc/mounts (was: Re: Linux 2.6.23-rc9 and a heads-up for the 2.6.24 series..) Message-ID: <20071003081213.4676ae60@laptopd505.fenrus.org> In-Reply-To: <20071003142600.GJ8181@ftp.linux.org.uk> References: <20071003084607.GC32218@elte.hu> <20071003133422.GI8181@ftp.linux.org.uk> <20071003140842.GA8837@elte.hu> <20071003142600.GJ8181@ftp.linux.org.uk> Organization: Intel X-Mailer: Claws Mail 3.0.1 (GTK+ 2.12.0; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1605 Lines: 40 On Wed, 3 Oct 2007 15:26:01 +0100 Al Viro wrote: > On Wed, Oct 03, 2007 at 04:08:42PM +0200, Ingo Molnar wrote: > > > Charming... So we get d_path() either returning junk or we get > > > something that isn't NUL-terminated. Which one it is? I.e. what > > > does p look like and what's in s? > > > > could be use-after-free as well, as CONFIG_PAGEALLOC was enabled. > > Umm... d_path() had just written there, so use-after-free is not too > likely to trigger page fault on read immediately afterwards - you'd > need a pretty tight race to hit it. I suspect we want the following patch out of general principles; Ingo, can you see if this one helps? (if not, it's still worth considering; it looks like we're first destroying the device object (which holds the name of the directory) before we unregister the directory... if that fails then we have a mess. Signed-off-by: Arjan van de Ven --- linux-2.6.23-rc2/net/wireless/core.c~ 2007-10-03 08:04:45.000000000 -0700 +++ linux-2.6.23-rc2/net/wireless/core.c 2007-10-03 08:04:45.000000000 -0700 @@ -133,8 +133,8 @@ void wiphy_unregister(struct wiphy *wiph mutex_unlock(&drv->mtx); list_del(&drv->list); - device_del(&drv->wiphy.dev); debugfs_remove(drv->wiphy.debugfsdir); + device_del(&drv->wiphy.dev); mutex_unlock(&cfg80211_drv_mutex); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/