Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933395Ab0FEN5g (ORCPT ); Sat, 5 Jun 2010 09:57:36 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:54092 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933280Ab0FEN5b convert rfc822-to-8bit (ORCPT ); Sat, 5 Jun 2010 09:57:31 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=V62J0TmGKxmzj3MPJTDgpL31ukpxg8PBKDI8d5+pk9vpNhm3a1TfMLlg54FP45V1ue PjQK/yONfNo3D6C/MQFAhJnsHIXMNZnCjz8XjD5iYjNORFWU8vzT/2tH2PhxIIuuOKFX ho7dXl+aSEkb9O+gyNwTD1IAG5EM5DEEmew2M= MIME-Version: 1.0 In-Reply-To: References: <20100604075148.5bcd7c8d@corrin.poochiereds.net> Date: Sat, 5 Jun 2010 08:57:30 -0500 Message-ID: Subject: Re: wait_even_interruptible_timeout(), signal, spin_lock() = system hang From: Shirish Pargaonkar To: Jeff Layton Cc: linux-kernel@vger.kernel.org, linux-fsdevel Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2428 Lines: 66 On Fri, Jun 4, 2010 at 7:13 AM, Shirish Pargaonkar wrote: > On Fri, Jun 4, 2010 at 6:51 AM, Jeff Layton wrote: >> On Fri, 28 May 2010 11:44:46 -0500 >> Shirish Pargaonkar wrote: >> >>> After this sequence of calls, system hangs (smp, x86 box based with >>> .34 kernel), can ping only. >>> I have not been able to break in with Alt Sysrq t, working on that >>> >>> ? ? ? ? rc = wait_event_interruptible_timeout(ses->server->response_q, >>> ? ? ? ? ? ? ? ? ? ? ? ? (midQ->midState != MID_REQUEST_SUBMITTED), timeout); >>> ? ? ? ? if (rc < 0) { >>> ? ? ? ? ? ? ? ? cFYI(1, ("command 0x%x interrupted", midQ->command)); >>> ? ? ? ? ? ? ? ? return -1; >>> ? ? ? ? } >>> >>> and when function that invoking function after coming out with ERESTARTSYS >>> (I kill the command with Ctrl C) calls >>> ?spin_lock(&GlobalMid_Lock); >>> >>> system hangs. ?If I sleep before return -1 (e.g. msleep(1), no hang) >>> >> >> Sounds like a race of some sort, but could also be that msleep() is >> doing something (perhaps relating to the pending signal) that prevents >> the hang. Without some sort of clue as to what the box is hung on at >> the time there is no way to know. >> >>> I do not have to use wait_event_interruptible_timeout and no such problems with >>> wait_event_timeout, it is only when signal/interrupt is involved, I >>> run into this problem >>> >>> Any pointers/ideas what could be happening, would be really really appreciated. >>> >> >> No idea right offhand. I'd suggest getting a core or sysrq data and see >> what it's doing. >> >> -- >> Jeff Layton >> > > Jeff, Thanks. ?The system hangs really hard. It does not respond to > Alt ScrLk ?Ctrl ScrLk > key sequence at the text mode console i.e. nothing gets logged in > /var/log/messages. > > Regards, > > Shirish > I think this is what is happening, when one fsstress command gets killed, one of the numerous processes that are getting killed holds mid lock and dies before releasing the lock and others when interrupted in wait return with ERESTARTSYS and while attempting the mid lock, spin forever causing system hang. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/