From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753350AbbLKTn3 (ORCPT ); Fri, 11 Dec 2015 14:43:29 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:35870 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753187AbbLKTnY (ORCPT ); Fri, 11 Dec 2015 14:43:24 -0500 Subject: Re: [PATCH] rt: x86: extend signal send delay to 32 bit To: Sebastian Andrzej Siewior References: <1449773931-7200-1-git-send-email-yang.shi@linaro.org> <20151211180532.GO6720@linutronix.de> Cc: tglx@linutronix.de, rostedt@goodmis.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, linaro-kernel@lists.linaro.org From: "Shi, Yang" Message-ID: <566B275A.5070300@linaro.org> Date: Fri, 11 Dec 2015 11:43:22 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20151211180532.GO6720@linutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/11/2015 10:05 AM, Sebastian Andrzej Siewior wrote: > * Yang Shi | 2015-12-10 10:58:51 [-0800]: > >> When running some ptrace single step tests on x86-32 machine, the below problem >> is triggered: >> >> BUG: sleeping function called from invalid context at linux-rt/kernel/locking/rtmutex.c:917 >> in_atomic(): 1, irqs_disabled(): 0, pid: 1041, name: dummy2 >> INFO: lockdep is turned off. >> Preemption disabled at:[] do_debug+0x1f/0x1a0 >> >> CPU: 10 PID: 1041 Comm: dummy2 Tainted: G W 4.1.13-rt13 #1 >> Hardware name: Intel Corporation S5520HC/S5520HC, BIOS S5500.86B.01.10.0025.030220091519 03/02/2009 >> 00000000 00000000 e1811e80 c1aa8306 00000000 e1811ea8 c1080517 c1d8b2e8 >> c100326f c100326f 00000411 e5b7d5b4 e1d521c4 00000005 e1811f74 e1811ec4 >> c1ab0eff e1d51cc0 e5b7d180 c1081403 e5b7d180 e5b7d180 e1811ee4 c1064b5a >> Call Trace: >> [] dump_stack+0x46/0x5c >> [] ___might_sleep+0x137/0x220 >> [] ? do_debug+0x1f/0x1a0 >> [] ? do_debug+0x1f/0x1a0 >> [] rt_spin_lock+0x1f/0x80 >> [] ? preempt_count_sub+0xb3/0x110 >> [] do_force_sig_info+0x2a/0xc0 >> [] force_sig_info+0xd/0x10 >> [] send_sigtrap+0x6f/0x80 >> [] do_debug+0x161/0x1a0 >> [] debug_stack_correct+0x2e/0x35 >> >> Signal send delay is just available for x86-64, x86-32 needs it too. > > This is new, this was not the case earlier. New means since v4.0-rc1 which Yes, it is. We didn't find this problem in earlier version kernel (I'd say 3.x). > is when 959274753857 ("x86, traps: Track entry into and exit from IST > context") got merged. > Since now ist_enter() disables preemption in any case, our hacks to > conditional_sti_ist() are pointless and could be removed. I'm supposed you will revert it and not need a revert patch from me. Thanks for the deeper cause analysis. Yang > > Sebastian >