Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752103Ab3JaBXJ (ORCPT ); Wed, 30 Oct 2013 21:23:09 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:21504 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750715Ab3JaBXH (ORCPT ); Wed, 30 Oct 2013 21:23:07 -0400 X-IronPort-AV: E=Sophos;i="4.93,605,1378828800"; d="scan'208";a="8904952" Message-ID: <5271AF91.4090109@cn.fujitsu.com> Date: Thu, 31 Oct 2013 09:17:05 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Tomi Valkeinen CC: Jean-Christophe PLAGNIOL-VILLARD , Linux Fbdev development list , linux-kernel Subject: Re: [RFC PATCH RESEND] fb: reorder the lock sequence to fix a potential lockdep References: <526DFDA8.7010806@cn.fujitsu.com> <5270EB85.1030103@ti.com> In-Reply-To: <5270EB85.1030103@ti.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/10/31 09:21:21, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/10/31 09:21:21, Serialize complete at 2013/10/31 09:21:21 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1112 Lines: 36 Hi Tomi, On 10/30/2013 07:20 PM, Tomi Valkeinen wrote: > Hi, > > On 2013-10-28 08:01, Gu Zheng wrote: >> Following commits: >> 50e244cc79 fb: rework locking to fix lock ordering on takeover >> e93a9a8687 fb: Yet another band-aid for fixing lockdep mess >> 054430e773 fbcon: fix locking harder >> >> reworked locking to fix related lock ordering on takeover, and introduced console_lock >> into fbmem, but it seems that the new lock sequence(fb_info->lock ---> console_lock) >> is against with the one in console_callback(console_lock ---> fb_info->lock), and leads to >> a potential deadlock as following: > > A quick grep shows that there are other places than fbmem.c which use > lock_fb_info and console_lock, for example drivers/video/sh_mobile_lcdcfb.c. Yes, thanks for your reminder, I'll fix them all in the next version. Regards, Gu > > Tomi > > -- 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/