From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from b.ns.miles-group.at ([95.130.255.144] helo=radon.swed.at) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W8PPQ-000109-1o for linux-mtd@lists.infradead.org; Wed, 29 Jan 2014 07:18:05 +0000 Message-ID: <52E8AB0F.2090905@nod.at> Date: Wed, 29 Jan 2014 08:17:35 +0100 From: Richard Weinberger MIME-Version: 1.0 To: "linux-mtd@lists.infradead.org" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] reproducable ubifs reboot assert and corruption References: <20140122051510.GB17284@gmail.com> <20140127163939.GA27809@gmail.com> <20140129053238.GA6035@gmail.com> In-Reply-To: <20140129053238.GA6035@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Am 29.01.2014 06:32, schrieb Andrew Ruder: > Ok, I've got some more useful information. I have been adding > a multitude of WARN_ON's and prink's all over the remount code and have > come up with the attached log. > > A little bit of explanation: > > Line 1: sync_filesystem (from do_remount_sb) > Line 188: sync_filesystem ends > Line 43, 64, 81, 98, 114, 135, 156, 173: write operations that occur > during sync_filesystem. Before each warning I print the inode pointer. > Line 197: read-only remount has completely finished (this message is > from userspace post remount) > Line 199: a sync is called, there are apparently dirty inodes in our > now-readonly ubifs filesystem > Line 215: failed assert that occurs because the writeback triggers for > inode 0xd75b9450 (see line 41, it got in with a sys_write while we were > running our sync_filesystem in do_remount_sb) > > Does this help? It looks like there is a race condition between the > writeback code and the remount read-only. Nothing is done to lock out > writes during the first half of the do_remount_sb and some stuff makes > it into the writeback worker queue while we are busy syncing the > filesystem only to trigger later when ubifs has decided it is > read-only... So you can trigger this by running fsstress on /mnt and then call mount -o remount,ro /mnt? Can you also trigger it on nandsim or mtdram? I did a quick test on my testbed using mtdram and was unable to trigger it. But I fear my box is too fast. Thanks, //richard