From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Shi, Yang" Subject: Re: [PATCH] rt: x86: extend signal send delay to 32 bit Date: Fri, 11 Dec 2015 11:43:22 -0800 Message-ID: <566B275A.5070300@linaro.org> References: <1449773931-7200-1-git-send-email-yang.shi@linaro.org> <20151211180532.GO6720@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: tglx@linutronix.de, rostedt@goodmis.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, linaro-kernel@lists.linaro.org To: Sebastian Andrzej Siewior Return-path: In-Reply-To: <20151211180532.GO6720@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.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 >