From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ted Ts'o Subject: Re: What am I doing wrong? submit_bio() suddenly stops working... Date: Thu, 21 Oct 2010 17:29:34 -0400 Message-ID: <20101021212934.GI3127@thunk.org> References: <4CBFE4E2.7050001@kernel.dk> <20101021165525.GB3127@thunk.org> <4CC07C67.9010502@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-kernel@vger.kernel.org" , "linux-ext4@vger.kernel.org" To: Jens Axboe Return-path: Received: from thunk.org ([69.25.196.29]:55204 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752931Ab0JUV3g (ORCPT ); Thu, 21 Oct 2010 17:29:36 -0400 Content-Disposition: inline In-Reply-To: <4CC07C67.9010502@kernel.dk> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Oct 21, 2010 at 07:46:15PM +0200, Jens Axboe wrote: > By the sound of things, if I were you I'd turn on the mem and slab > debugging to catch use-before-init and use-after-free. Mysterious hangs > in the IO sub system are usually caused by such bugs. And the regular > debugging aids, just to see if that produces anything of interest. I've tried turning on slub_debug=FZP, and that didn't turn up anything. Looking at the traces, it looks like the queue gets plugged near the end, but then I don't see an unplug timer event. I'm not sure what could cuase that, though... - Ted