Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754421AbcCUKl5 (ORCPT ); Mon, 21 Mar 2016 06:41:57 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:16839 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753344AbcCUKlu (ORCPT ); Mon, 21 Mar 2016 06:41:50 -0400 Subject: Re: [PATCH 2/2] arm64: Fix watchpoint recursion when single-step is wrongly triggered in irq To: Pratyush Anand , He Kuang References: <1458549470-124791-1-git-send-email-hekuang@huawei.com> <1458549470-124791-2-git-send-email-hekuang@huawei.com> <20160321102423.GB15150@dhcppc6.redhat.com> CC: , , , , , , , , , , , From: "Wangnan (F)" Message-ID: <56EFCF27.3090903@huawei.com> Date: Mon, 21 Mar 2016 18:38:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <20160321102423.GB15150@dhcppc6.redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.66.109] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.56EFCF41.00F4,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 072bba0174c02b63e03ed9cbcfb93434 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 848 Lines: 22 On 2016/3/21 18:24, Pratyush Anand wrote: > On 21/03/2016:08:37:50 AM, He Kuang wrote: >> On arm64, watchpoint handler enables single-step to bypass the next >> instruction for not recursive enter. If an irq is triggered right >> after the watchpoint, a single-step will be wrongly triggered in irq >> handler, which causes the watchpoint address not stepped over and >> system hang. > Does patch [1] resolves this issue as well? I hope it should. Patch[1] has still > not been sent for review. Your test result will be helpful. > > ~Pratyush > > [1] https://github.com/pratyushanand/linux/commit/7623c8099ac22eaa00e7e0f52430f7a4bd154652 Could you please provide a test program for your case so we can test it on our devices? I guess setting breakpoint on a "copy_from_user()" accessing an invalid address can trigger this problem? Thank you.