Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755685AbZDKGC3 (ORCPT ); Sat, 11 Apr 2009 02:02:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754655AbZDKGCT (ORCPT ); Sat, 11 Apr 2009 02:02:19 -0400 Received: from smtp239.poczta.interia.pl ([217.74.64.239]:49232 "EHLO smtp239.poczta.interia.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754470AbZDKGCS (ORCPT ); Sat, 11 Apr 2009 02:02:18 -0400 Date: Sat, 11 Apr 2009 08:04:15 +0200 From: Krzysztof Helt To: Andrea Righi Cc: Eric Miao , LKML , Geert Uytterhoeven , Andrew Morton , "Rafael J. Wysocki" , Andrey Borzenkov , "Antonino A. Daplas" , linux-fbdev-devel@lists.sourceforge.net, linux-pm@lists.linux-foundation.org, Dave Jones , Harvey Harrison , Johannes Weiner , Stefan Richter Subject: Re: [REGRESSION] commit 66c1ca0: {fbmem: fix fb_info->lock and mm->mmap_sem ...} causes Xfbdev not working Message-Id: <20090411080415.7fe924a2.krzysztof.h1@poczta.fm> In-Reply-To: <20090410220521.GB21294@linux> References: <20090409125850.GA2727@linux> <20090410222122.87be60f6.krzysztof.h1@poczta.fm> <20090410220521.GB21294@linux> X-Mailer: Sylpheed 2.4.3 (GTK+ 2.11.0; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-EMID: 14e2b138 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1019 Lines: 28 On Sat, 11 Apr 2009 00:05:22 +0200 Andrea Righi wrote: > > mmmh... I may have missed something, but the common fb_mmap() should > acquire mm->mmap_sem and then info->lock, while fb_ioctl() can do that > in reverse order (info->lock first and then mm->mmap_sem) causing the > circular locking dependency. Are you sure that pushing info->lock down > each driver's fb_mmap will fix the problem? Right. The fb_mmap is called with the mmap_sem already held. I will try other possibilities like breaking info->lock() into two mutexex. Something should be done to solve this problem. Best regards, Krzysztof ---------------------------------------------------------------------- Oblej swoich znajomych... wirtualnie! ;) http://link.interia.pl/f2119 -- 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/