Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751185AbWHTTuU (ORCPT ); Sun, 20 Aug 2006 15:50:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751194AbWHTTuU (ORCPT ); Sun, 20 Aug 2006 15:50:20 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:33492 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1751185AbWHTTuT (ORCPT ); Sun, 20 Aug 2006 15:50:19 -0400 Subject: Re: Possible deadlock in videobuf_dma_init_user From: Arjan van de Ven To: Petr Vandrovec Cc: video4linux-list@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <20060820191930.GA21729@platan.vc.cvut.cz> References: <20060820191930.GA21729@platan.vc.cvut.cz> Content-Type: text/plain Organization: Intel International BV Date: Sun, 20 Aug 2006 21:50:15 +0200 Message-Id: <1156103415.23756.58.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 700 Lines: 28 On Sun, 2006-08-20 at 21:19 +0200, Petr Vandrovec wrote: > Hello, > my kernel is a bit unhappy with lock ordering between mm->mmap_sem > and videobuf_queue->lock. > Thanks, > Petr Vandrovec looks like a real deadlock to me... bttv_prepare_buffer takes mutex then videobuf_dma_init_user takes mmap_sem do_mmap_pgoff takes mmap_sem then calls bttv_mmap which calls videobuf_mmap_mapper takes the mutex so a classic AB-BA deadlock.... - 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/