From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A500C10F0E for ; Mon, 15 Apr 2019 12:58:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBF872064A for ; Mon, 15 Apr 2019 12:58:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="cO67aSDH"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="cO67aSDH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727353AbfDOM6b (ORCPT ); Mon, 15 Apr 2019 08:58:31 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:57054 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727129AbfDOM6b (ORCPT ); Mon, 15 Apr 2019 08:58:31 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 7E37A6155E; Mon, 15 Apr 2019 12:58:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1555333110; bh=agln/OUqOYAxaGAnB9UBlUR029eFopQS7xCI98I8qmE=; h=To:Cc:From:Subject:Date:From; b=cO67aSDHpLlsJEy9Coa1f7MZzl2HWAT0V0yvA6UZMJpXaIUq8kBrlOdhvw563x0pX +9hzFn3TmJl3UWUfpA58UYKcidAteNBVkZHGrjzGpftKG3YR3bPLIPUXBah8cYsQ7Y iVKx52AHhdgky9W1fP/+2eYf2c4QFtCFILxJg4cY= Received: from [10.204.82.67] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: shajit@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 27E996119F; Mon, 15 Apr 2019 12:58:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1555333110; bh=agln/OUqOYAxaGAnB9UBlUR029eFopQS7xCI98I8qmE=; h=To:Cc:From:Subject:Date:From; b=cO67aSDHpLlsJEy9Coa1f7MZzl2HWAT0V0yvA6UZMJpXaIUq8kBrlOdhvw563x0pX +9hzFn3TmJl3UWUfpA58UYKcidAteNBVkZHGrjzGpftKG3YR3bPLIPUXBah8cYsQ7Y iVKx52AHhdgky9W1fP/+2eYf2c4QFtCFILxJg4cY= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 27E996119F 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=shajit@codeaurora.org To: keescook@chromium.org, mcgrof@kernel.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-msm@vger.kernel.org From: Jitendra Sharma Subject: fs/proc: Crash observed in next_tgid (fs/proc/base.c) Message-ID: Date: Mon, 15 Apr 2019 18:28:25 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Kees Cook/Luis, We are observing one kernel crash in next_tgid function through getdents64 path. Call stack is as shown below: -000|has_group_leader_pid(inline) -000|next_tgid( | [X20] ns = 0xFFFFFF87CABB1AC0, | [locdesc] iter = ( | [locdesc] tgid = 424, | [locdesc] task = ?)) | [X21] p = 0xFFFFFFD0FFFFF948 | [X21] task = 0xFFFFFFD0FFFFF948 -001|proc_pid_readdir( | [X20] file = 0xFFFFFFD1AC60FC40, | [X19] ctx = 0xFFFFFF8027363E40) | [X21] ns = 0xFFFFFF87CABB1AC0 -002|proc_root_readdir( | [X20] file = 0xFFFFFFD1AC60FC40, | [X19] ctx = 0xFFFFFF8027363E40) -003|iterate_dir( | [X19] file = 0xFFFFFFD1AC60FC40, | [X22] ctx = 0xFFFFFF8027363E40) | [X23] inode = 0xFFFFFFD1F20246D0 -004|SYSC_getdents64(inline) -004|sys_getdents64( | ?, | ?, | [X19] count = 4200) | [X19] count = 4200 | [X20] f = ([X20] file = 0xAC60FC43AC60FC40, [X20] flags = 1207898624) | [X0] error = -1720 -005|el0_svc_naked(asm) -->|exception -006|NUX:0x78C5AD7D38(asm) ---|end of frame From this call stack,task: 0xFFFFFFD0FFFFF948, seems to be invalid. As(from ramdumps) it doesn't have any valid fields. And while trying to access the fields of this task struct in has_group_leader_pid, abort is happening. From the dumps, its not clear why the task struct is coming to be some invalid (Possibly task has already exited). This issue is observed during normal monkey testing for long hours. Could you please provide some pointers which could help in debugging this issue further. Thanks, Jitendra -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation