From: Jeff Moyer Subject: Re: Null pointer deref in do_aio_submit Date: Fri, 10 Feb 2012 13:06:32 -0500 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Sage Weil Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8977 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750831Ab2BJSGe (ORCPT ); Fri, 10 Feb 2012 13:06:34 -0500 In-Reply-To: (Sage Weil's message of "Fri, 10 Feb 2012 09:27:51 -0800 (PST)") Sender: linux-ext4-owner@vger.kernel.org List-ID: Sage Weil writes: > I hit the following under a reasonable simple aio workload: > > - reasonably heavy load > - lots of threads doing buffered io to random files > - one thread submitting O_DIRECT aio to a single file (journal), all > sequential (wrapping), 100MB > - probably somewhere between 1 and 50 aios outstanding at any point in > time. > > The kernel was v3.2 mainline, plus unrelated btrfs and ceph patches. > > Is this a known issue? Any other information that would be helpful? I don't know for sure, but could you test with the following commit? 69e4747ee9727d660b88d7e1efe0f4afcb35db1b Also, I'll note that it looks like you are doing O_SYNC + O_DIRECT AIO. I'm curious to know what apps use that particular combination. Is this just a test case, or do you have an app which does this in production? Cheers, Jeff