From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751170AbWERIDK (ORCPT ); Thu, 18 May 2006 04:03:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751177AbWERIDK (ORCPT ); Thu, 18 May 2006 04:03:10 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:52454 "EHLO mx3.mail.elte.hu") by vger.kernel.org with ESMTP id S1751170AbWERIDI (ORCPT ); Thu, 18 May 2006 04:03:08 -0400 Date: Thu, 18 May 2006 10:03:09 +0200 From: Ingo Molnar To: Daniel Walker Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH -rt] free_pgtables deadlock Message-ID: <20060518080308.GC30387@elte.hu> References: <200605141604.k4EG4oQ1005635@dwalker1.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200605141604.k4EG4oQ1005635@dwalker1.mvista.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=no SpamAssassin version=3.0.3 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Daniel Walker wrote: > Following is a fix for this deadlock . > > What's happening is task 2 holds the i_mmap_lock from unmap_region(), > then it enters zap_page_range() where it tried to acquire the locked > mmu_gathers percpu . > > While task 1) holds the mmu_gathers percpu lock from unmap_region() > and then tried to aquire i_mmap_lock inside unlink_file_vma() . > > It looks like it's possible to drop the mmu_gathers prior to calling > unlink_file_vma() , but it's only done if there's more than one vma . > > This deadlock was seen by Deepak Saxena on an ARM Versatile board. thanks, applied. Ingo