From: Andreas Dilger Subject: Re: EXT4: kernel BUG at fs/jbd2/commit.c:533! Date: Wed, 02 Sep 2009 15:07:37 -0600 Message-ID: <20090902210737.GV4197@webber.adilger.int> References: <4A9E5496.8050909@in.ibm.com> <20090902120958.GA16415@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Sachin Sant , linux-ext4@vger.kernel.org To: Theodore Tso Return-path: Received: from sca-es-mail-2.Sun.COM ([192.18.43.133]:54235 "EHLO sca-es-mail-2.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130AbZIBVH2 (ORCPT ); Wed, 2 Sep 2009 17:07:28 -0400 Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-2.sun.com (8.13.7+Sun/8.12.9) with ESMTP id n82L7UER016692 for ; Wed, 2 Sep 2009 14:07:30 -0700 (PDT) Content-disposition: inline Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KPD00C003QOFF00@fe-sfbay-09.sun.com> for linux-ext4@vger.kernel.org; Wed, 02 Sep 2009 14:07:30 -0700 (PDT) In-reply-to: <20090902120958.GA16415@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sep 02, 2009 08:09 -0400, Theodore Ts'o wrote: > On Wed, Sep 02, 2009 at 04:48:46PM +0530, Sachin Sant wrote: > > While executing fsstress against ext4 with 2.6.31-rc8 on a > > powerpc box, ran into the following Bug. > > > > ------------[ cut here ]------------ > > cpu 0x0: Vector: 700 (Program Check) at [c0000000f3ae3970] > > pc: c000000000280f28: .jbd2_journal_commit_transaction+0x8ac/0x1bfc > > lr: c000000000280e58: .jbd2_journal_commit_transaction+0x7dc/0x1bfc > > sp: c0000000f3ae3bf0 > > msr: 8000000000029032 > > current = 0xc0000000f315c7d0 > > paca = 0xc000000000b62600 > > pid = 23139, comm = kjournald2 > > kernel BUG at fs/jbd2/commit.c:533! > > Hmm, that's this ASSERT: > > J_ASSERT(commit_transaction->t_nr_buffers <= > commit_transaction->t_outstanding_credits); > > in jbd2_journal_commit_transaction(). That's not something I've ever > seen before, nor have we made any changes in the jbd2 logic in quite > some time that would could be related to that code. > > Is it possible to extract out the contents of the commit_transaction > structure? In particular, the t_nr_buffers and t_outstanding_credits value? > > At this point, I can't rule out a wild pointer corrupting the data > structure, however improbable that sounds... Given the nature of the test being run (fsstress) it seems entirely possible that there is some transaction which doesn't reserve enough credits for the operation in some rare corner case? Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.