From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20DB0C32750 for ; Fri, 2 Aug 2019 15:30:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0F842087C for ; Fri, 2 Aug 2019 15:30:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733128AbfHBPa0 (ORCPT ); Fri, 2 Aug 2019 11:30:26 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:39873 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732277AbfHBPaZ (ORCPT ); Fri, 2 Aug 2019 11:30:25 -0400 Received: from [5.158.153.52] (helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1htZV2-0002wy-PP; Fri, 02 Aug 2019 17:29:45 +0200 Date: Fri, 2 Aug 2019 17:29:43 +0200 (CEST) From: Thomas Gleixner To: Jan Kara cc: LKML , Peter Zijlstra , Ingo Molnar , Sebastian Siewior , Anna-Maria Gleixner , Steven Rostedt , Julia Cartwright , Jan Kara , Theodore Tso , Mark Fasheh , Joseph Qi , Joel Becker , linux-ext4@vger.kernel.org, Matthew Wilcox , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: Re: [patch V2 6/7] fs/jbd2: Make state lock a spinlock In-Reply-To: <20190802133714.GN25064@quack2.suse.cz> Message-ID: References: <20190801010126.245731659@linutronix.de> <20190801010944.457499601@linutronix.de> <20190801175703.GH25064@quack2.suse.cz> <20190802133714.GN25064@quack2.suse.cz> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2 Aug 2019, Jan Kara wrote: > On Thu 01-08-19 20:12:11, Thomas Gleixner wrote: > > On Thu, 1 Aug 2019, Jan Kara wrote: > > > On Thu 01-08-19 03:01:32, Thomas Gleixner wrote: > > > > As almost all functions which use this lock have a journal head pointer > > > > readily available, it makes more sense to remove the lock helper inlines > > > > and write out spin_*lock() at all call sites. > > > > > > > > > > Just a heads up that I didn't miss this patch. Just it has some bugs and I > > > figured that rather than explaining to you subtleties of jh lifetime it is > > > easier to fix up the problems myself since you're probably not keen on > > > becoming jbd2 developer ;)... which was more complex than I thought so I'm > > > not completely done yet. Hopefuly tomorrow. > > > > I'm curious where I was too naive :) > > Well, the most obvious where places where the result ended up being like > > jbd2_journal_put_journal_head(jh); > spin_unlock(&jh->state_lock); > > That's possible use-after-free. Duh yes. > But there were also other more subtle places where > jbd2_journal_put_journal_head() was not directly visible as it was hidden > inside journal list handling functions such as __jbd2_journal_refile_buffer() > or so. And these needed some more work. > > Anyway, I'm now done fixing up the patch, doing some xfstests runs to verify > things didn't break in any obvious way... Very appreciated. Thanks, tglx