From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932483AbeCMRZM (ORCPT ); Tue, 13 Mar 2018 13:25:12 -0400 Received: from foss.arm.com ([217.140.101.70]:42130 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932312AbeCMRZL (ORCPT ); Tue, 13 Mar 2018 13:25:11 -0400 Subject: Re: [PATCH] arm64: kdump: fix interrupt handling done during machine_crash_shutdown To: Grzegorz Jaszczyk , Mark Rutland Cc: Hoeun Ryu , catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, Nadav Haklai , "AKASHI, Takahiro" , james.morse@arm.com, Marcin Wojtas , linux-arm-kernel@lists.infradead.org References: <1519837260-30662-1-git-send-email-jaz@semihalf.com> <20180228171647.6t4dabntujcb5kon@lakrids.cambridge.arm.com> <20180302120556.xujh3hoy44y7ouz7@lakrids.cambridge.arm.com> <20180302131545.q2vf6uc3yofofqdb@lakrids.cambridge.arm.com> <20180302164411.fxdx72ttz7livz2e@lakrids.cambridge.arm.com> <20180302165739.dc726v3yf2mxli3u@lakrids.cambridge.arm.com> From: Marc Zyngier Organization: ARM Ltd Message-ID: Date: Tue, 13 Mar 2018 17:25:07 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/03/18 22:06, Grzegorz Jaszczyk wrote: > 2018-03-02 17:57 GMT+01:00 Mark Rutland : >>>>> Do you see this for a panic() in *any* interrupt handler? >>>> >>>> I only test with this two interrupt handlers: watchdog and i2c but I >>>> think it will behave the same with others - I can try with other if >>>> you want, any suggestion which? Maybe with some PPI interrupt instead? > > I was able to reproduce it from other interrupts handler (UART, I2C, > timer and watchdog) no difference if it is PPI or SPI interrupt. I > also reproduce this issue with GICv3. But again it only happens when > eoimode = 0. >>>>> >>>>> Can you trigger the issue with magic-sysrq c, for example? >>>> >>>> There is no problem when I trigger it via 'echo c > >>>> /proc/sysrq-trigger' - it works well all the time. The problem appears >>>> only, when the kexec/kdump procedure is triggered from interrupt >>>> context >>> >>> I'd meant that you'd send sysrq + c over serial, rather than writing to >>> /proc/sysrq-trigger. That way, the panic will be in the context of the >>> UART IRQ handler. >>> >>> If that shows the issue, that's ilikely to be the easiest way for >>> someone else to reproduce and investigate this. > > Yes it can be triggered by sending sysrq + c and indeed it is the > easiest way to reproduce it. >> >> FWIW, having just given this a go on my Juno R1 with v4.16-rc3 >> defconfig, the UART IRQs work fine in the crash kernel. That crash >> happened in IRQ context: > > I think that by default Juno uses eoimode = 1, did you try it when > eoimode was forced to be 0? Only eoimode = 0 triggers the issue. FWIW, I've now posted fixes to LKML[1]. Feel free to test them and report whether they fix the issue for you. Thanks, M. [1] https://lkml.org/lkml/2018/3/13/1088 -- Jazz is not dead. It just smells funny...