Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750918AbeAPFgx (ORCPT + 1 other); Tue, 16 Jan 2018 00:36:53 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:55884 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750725AbeAPFgw (ORCPT ); Tue, 16 Jan 2018 00:36:52 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 3FF6260262 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=gkohli@codeaurora.org Subject: Re: Query: Crash is coming during /prod/PID/stat and do_exit of same task To: Alexey Dobriyan Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20180110052017.GB2829@avx2> From: "Kohli, Gaurav" Message-ID: Date: Tue, 16 Jan 2018 11:06:47 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180110052017.GB2829@avx2> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 1/10/2018 10:50 AM, Alexey Dobriyan wrote: >> We are seeing crash in do_task_stat while accessing stack pointer, It >> seems same task has already completed do_exit call. >> So it seems a race between them: > Please, post exact kernel version and struct task_struct::usage if you > still have that kernel core (or even full task_struct) Hi Alexey, We are working on 4.9.65 and Please find below usage value and other task_struct value, please let me know if some other data required as well. crash_64> struct task_struct.usage -x  0xFFFFFFE80D8C2280   usage = {     counter = 0x4   } struct task_struct.flags -x 0xFFFFFFE80D8C2280   flags = 0x40870c crash_64> struct task_struct.exit_code -x 0xFFFFFFE80D8C2280   exit_code = 0x6  struct task_struct.state -x 0xFFFFFFE80D8C2280   state = 0x40 Please find below crash stack: -000|user_stack_pointer(inline) -000|do_task_stat(     |    m = 0xFFFFFFE7A5CD7380,     |    ns = 0xFFFFFF8E7C43C748,     |  ?,     |    task = 0xFFFFFFE80D8C2280,     |  ?)     |  tty_pgrp = 0     |  ppid = 2084696064     |  sid = 0     |  mm = 0xFFFFFFE7B4424140     |  tcomm = (84, 9, 71, 122, 142, 255, 255, 255, 48, 253, 240, 165, 231, 255, 255, 255)     |  flags = 18446743969119403392 -001|proc_tgid_stat(     |    m = 0xFFFFFFE7A5CD7380,     |  ?,     |  ?,     |  ?) -002|atomic_sub_return(inline) Regards Gaurav -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.