From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Young Subject: Re: [RT] Lockdep warning on boot with 2.6.31-rc5-rt1.1 Date: Sat, 8 Aug 2009 11:20:29 +0800 Message-ID: References: <20090807094608.4b0efea1@torg> <1249657743.32113.733.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Clark Williams , LKML , RT , Thomas Gleixner , Alan Stern , "greg@kroah.com" , "Rafael J. Wysocki" , Kay Sievers To: Peter Zijlstra Return-path: Received: from mail-fx0-f228.google.com ([209.85.220.228]:56517 "EHLO mail-fx0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932900AbZHHDU3 convert rfc822-to-8bit (ORCPT ); Fri, 7 Aug 2009 23:20:29 -0400 In-Reply-To: <1249657743.32113.733.camel@twins> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Fri, Aug 7, 2009 at 11:09 PM, Peter Zijlstra w= rote: > On Fri, 2009-08-07 at 09:46 -0500, Clark Williams wrote: >> Peter, >> >> I'm getting this warning from lockdep when booting on my T60. >> >> The two addresses reported (0xffffffff812664a2 and 0xffffffff812664a= e) >> actually bracket one call to mutex_lock() in driver_attach() so I'm = not >> sure what the complaint is. >> >> Clark >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >> [ INFO: possible recursive locking detected ] >> 2.6.31-rc5-rt1.1 #37 >> --------------------------------------------- >> swapper/1 is trying to acquire lock: >> =C2=A0(&dev->mutex){+.+...}, at: [] >> __driver_attach+0x48/0x81 >> >> but task is already holding lock: >> =C2=A0(&dev->mutex){+.+...}, at: [] >> __driver_attach+0x3c/0x81 >> >> other info that might help us debug this: >> 1 lock held by swapper/1: >> =C2=A0#0: =C2=A0(&dev->mutex){+.+...}, at: [] >> __driver_attach+0x3c/0x81 > > Oh, that's tglx who's gone wild with sem->mutex conversions. > > It used to be that _all_ dev->sem instances were taken on suspend or > something like that, I think that got fixed a long while back. > > I'd have to look at what the current locking requirements for dev->se= m > are. > > I remember talking to Alan on several occasions about this, and I jus= t > went over some of the old emails, but I must say the precise > requirements stay hidden from me. Also, I'm not sure these emails are > still representative of the current state. I think you means this thread: http://lkml.org/lkml/2008/4/17/305 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kerne= l" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > Please read the FAQ at =C2=A0http://www.tux.org/lkml/ > --=20 Regards dave -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933052AbZHHDUb (ORCPT ); Fri, 7 Aug 2009 23:20:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932966AbZHHDUa (ORCPT ); Fri, 7 Aug 2009 23:20:30 -0400 Received: from mail-fx0-f228.google.com ([209.85.220.228]:56517 "EHLO mail-fx0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932900AbZHHDU3 convert rfc822-to-8bit (ORCPT ); Fri, 7 Aug 2009 23:20:29 -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=GpB6/A5WTnMEMvhaGmLsSlnlcyOhDXIoyX2PyRbVgt7FxiFmX2hlCycCKb90oTwFP6 YSq+QR35LGtOQWj4GUk/niyVxnHHjtmIYUviXvhnifNGtEtFFj8hG9M2dmQVyCr2yPZB a+M+ojYMf3lZjMVlbOxPCa6Ceif47ANI3df/o= MIME-Version: 1.0 In-Reply-To: <1249657743.32113.733.camel@twins> References: <20090807094608.4b0efea1@torg> <1249657743.32113.733.camel@twins> Date: Sat, 8 Aug 2009 11:20:29 +0800 Message-ID: Subject: Re: [RT] Lockdep warning on boot with 2.6.31-rc5-rt1.1 From: Dave Young To: Peter Zijlstra Cc: Clark Williams , LKML , RT , Thomas Gleixner , Alan Stern , "greg@kroah.com" , "Rafael J. Wysocki" , Kay Sievers Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 7, 2009 at 11:09 PM, Peter Zijlstra wrote: > On Fri, 2009-08-07 at 09:46 -0500, Clark Williams wrote: >> Peter, >> >> I'm getting this warning from lockdep when booting on my T60. >> >> The two addresses reported (0xffffffff812664a2 and 0xffffffff812664ae) >> actually bracket one call to mutex_lock() in driver_attach() so I'm not >> sure what the complaint is. >> >> Clark >> >> ============================================= >> [ INFO: possible recursive locking detected ] >> 2.6.31-rc5-rt1.1 #37 >> --------------------------------------------- >> swapper/1 is trying to acquire lock: >>  (&dev->mutex){+.+...}, at: [] >> __driver_attach+0x48/0x81 >> >> but task is already holding lock: >>  (&dev->mutex){+.+...}, at: [] >> __driver_attach+0x3c/0x81 >> >> other info that might help us debug this: >> 1 lock held by swapper/1: >>  #0:  (&dev->mutex){+.+...}, at: [] >> __driver_attach+0x3c/0x81 > > Oh, that's tglx who's gone wild with sem->mutex conversions. > > It used to be that _all_ dev->sem instances were taken on suspend or > something like that, I think that got fixed a long while back. > > I'd have to look at what the current locking requirements for dev->sem > are. > > I remember talking to Alan on several occasions about this, and I just > went over some of the old emails, but I must say the precise > requirements stay hidden from me. Also, I'm not sure these emails are > still representative of the current state. I think you means this thread: http://lkml.org/lkml/2008/4/17/305 > > -- > 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/ > -- Regards dave