From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: [BUG] 3.12 vfs weirdness under load Date: Wed, 13 Nov 2013 01:05:58 -0500 Message-ID: <20131113060557.GA29660@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Waiman Long , Al Viro To: linux-fsdevel@vger.kernel.org Return-path: Received: from cloud.peff.net ([50.56.180.127]:38248 "HELO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751499Ab3KMGMl (ORCPT ); Wed, 13 Nov 2013 01:12:41 -0500 Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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. Git's test suite puts a lot of load on the VFS; re-running failed tests individually when the system is unloaded lets them pass. I haven't been able to get a specific syscall strace of what's going on, but some of the failures I investigated had obvious oddness, like "grep foo bar" returning non-zero, but then looking in "bar" manually shows that it contains the expected content. I bisected this to 232d2d6 (dcache: Translating dentry into pathname without taking rename_lock, 2013-09-09), and can reliably reproduce the problem (and running with the parent ac83871 reliably works). I see the problem on my ext4-over-dmcrypt disk, but also when running the tests on a tmpfs disk. So I don't think it's filesystem-specific. 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. -Peff