From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [BUG] 3.12 vfs weirdness under load Date: Wed, 13 Nov 2013 21:40:53 +0000 Message-ID: <20131113214053.GF13318@ZenIV.linux.org.uk> References: <20131113060557.GA29660@sigill.intra.peff.net> <20131113213605.GA7043@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, Waiman Long To: Jeff King Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:47285 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874Ab3KMVkz (ORCPT ); Wed, 13 Nov 2013 16:40:55 -0500 Content-Disposition: inline In-Reply-To: <20131113213605.GA7043@sigill.intra.peff.net> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Nov 13, 2013 at 04:36:06PM -0500, Jeff King wrote: > On Wed, Nov 13, 2013 at 01:05:58AM -0500, Jeff King wrote: > > > On v3.12, running "make -j16 test" on a git.git checkout produces random > > failures in the test suite, whereas it works fine on v3.11. > > [...] > > Reading the patch for 232d2d6, it seems plausible that it's a locking > > problem in the new code, but I don't see anything obviously wrong. I'd > > expect others can reproduce by running git's test suite, but if not, I'm > > happy to test patches. > > A word of warning to anyone who wants to reproduce this: I believe it > caused some data loss during my bisect. Git's test suite does a lot of: > > mkdir trash.XXXXX > ... do some tests in trash.XXXXX > rm -rf trash.XXXXX > > >From reading the patch, I'm guessing the bug is causing wrong dir > entries to be returned under load. Random bits of my home directory are > missing this morning after my testing; my theory is that when we are > unlucky enough to hit the race on the "rm", it can end up deleting > random things. Move initialization of dentry/vfsmount/mnt to just before the loop in prepend_path() and see if that fixes what you are seeing...