From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756150Ab3BEPyK (ORCPT ); Tue, 5 Feb 2013 10:54:10 -0500 Received: from lennier.cc.vt.edu ([198.82.162.213]:55167 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755858Ab3BEPyF (ORCPT ); Tue, 5 Feb 2013 10:54:05 -0500 X-Mailer: exmh version 2.8.0 04/21/2012 with nmh-1.4-dev To: Kent Overstreet Cc: Andrew Morton , Hillf Danton , Benjamin LaHaise , linux-kernel@vger.kernel.org, linux-aio@kvack.org Subject: Re: next-20130117 - kernel BUG with aio In-Reply-To: Your message of "Thu, 31 Jan 2013 16:37:27 -0800." <20130201003727.GK12631@moria.home.lan> From: Valdis.Kletnieks@vt.edu References: <3544.1358774694@turing-police.cc.vt.edu> <2553.1358890098@turing-police.cc.vt.edu> <20130131135952.77cf5d3a.akpm@linux-foundation.org> <20130201003727.GK12631@moria.home.lan> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1360079580_2221P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Tue, 05 Feb 2013 10:53:00 -0500 Message-ID: <5602.1360079580@turing-police.cc.vt.edu> X-Mirapoint-Received-SPF: 198.82.161.152 auth3.smtp.vt.edu Valdis.Kletnieks@vt.edu 2 pass X-Junkmail-Status: score=10/50, host=zidane.cc.vt.edu X-Junkmail-Signature-Raw: score=unknown, refid=str=0001.0A020203.51112ADE.0001,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2011-07-25 19:15:43, dmn=2011-05-27 18:58:46, mode=single engine X-Junkmail-IWF: false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1360079580_2221P Content-Type: text/plain; charset=us-ascii On Thu, 31 Jan 2013 16:37:27 -0800, Kent Overstreet said: > On Thu, Jan 31, 2013 at 01:59:52PM -0800, Andrew Morton wrote: > > Did this get fixed? > With the patches I sent you, yes - not seeing a new linux-next tree yet? Well, it's a mixed bag at my end. Finally got a chance to do some more testing, and: 1) next-20130128 didn't show anything in dmesg, but my VirtualBox Windows 7 images appear to livelock on the way up - the Windows throbber would keep going, but it never made any actual progress towards booting. (Part of the delay was fixing a next-20121224 environment, and then discovering it took Windows *two* reboot cycles to get its act back together after getting into that hung state). 2_ next-20130128 plus the following 3 patches: Subject: [PATCH 1/3] aio: Fix a null pointer deref in batch_complete_aio Subject: [PATCH 3/3] aio-use-cancellation-list-lazily-fix Subject: [PATCH 2/3] aio-kill-ki_retry-fix-fix VirtualBox appears to be functional (I did 2 complete boot/shutdown sequences of both a 32-bit and 64-bit Win7 Enterprise image). *HOWEVER*, I saw 3 of these in dmesg: [ 668.278624] WARNING: at fs/aio.c:348 put_ioctx+0x1c0/0x241() [ 668.278652] Call Trace: [ 668.278660] [] warn_slowpath_common+0x7c/0x96 [ 668.278665] [] warn_slowpath_null+0x15/0x17 [ 668.278669] [] put_ioctx+0x1c0/0x241 [ 668.278673] [] sys_io_destroy+0x4c/0x5c [ 668.278679] [] system_call_fastpath+0x16/0x1b and the code there says: WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr); which leaves me wondering exactly how we exited the while loop just above - is the intention that it loop until reqs_available == ctx->nr exactly? Looks like if 'avail' is anything other than exactly 1 in that while loop, we can be at a state where reqs_avail == (ctx->nr -1), get 'avail=2', do the atomic_add, fall out of the loop, and trigger the WARN_ON. Damned if I see how that can happen though.... --==_Exmh_1360079580_2221P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iQIVAwUBUREq3AdmEQWDXROgAQIKuw//f7e6rfYunhFaUp0Zrr25eKJqn8b2CeXB VaC7ZYnC21He1cyxm96L3GZeuj2VQjIWiPbJ7oEVtXAqn8cZ4O2HG3t+Ps74iBnJ 5NrCf/pf3plm8LOOqoX7jd3IiLqaSUJ5rbSITEOPzsnGPrl5Pe1oLPJmzinslLxf NHSX9iyZhPht25229TUb+UTG7Do85yoS/RAnexd9XgK8NO0EkDo8Rmfus/0zKi/D gDuZOSY/aasJZ2fsJKmnmkE6OsAtBsqy+VcM6n0oebaBOIa7C/AiG4mwYYYBTROr ejajbcPfnEl06ArebIxQlCk87rab/pUy+bsX/iJ7SU34/4BXqZtUhszs5BbkwHDt Pbi0cRN6zPtx+erG2hkJdWD+QiYAOLsCBxPQy+gAGHniyTdGb5VLRrQz+pPpt5Pg IugoJd2UVoj+4PBw8afSVYdd4znRZfzBuelstlnYw1e0xnTBfcHQmcV/xGiY+18i 0QvqYSizQW2VP8AkZ96rkHCvLYnbl0flXTT3Nho/g5e6CW69lqY4RDPwPwRi/v2D 2C2cIOUGdqHYn5TM62byXGtmIIGC0RnOPxMy+EXKjBrwmIqP7BUVSGfj1LOp1vZd ymZV4xguBA5pVBI3z7mzu2iNxywgZ+SUlZa+9B2+AZavdiXBnHDDcTVIpAiMi2V0 rEug9flbyXU= =Uf5x -----END PGP SIGNATURE----- --==_Exmh_1360079580_2221P--