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=-7.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 3530DC10F13 for ; Mon, 8 Apr 2019 19:35:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E42682083E for ; Mon, 8 Apr 2019 19:35:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="vCOXEuCT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727199AbfDHTfR (ORCPT ); Mon, 8 Apr 2019 15:35:17 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40894 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726403AbfDHTfR (ORCPT ); Mon, 8 Apr 2019 15:35:17 -0400 Received: by mail-pf1-f194.google.com with SMTP id c207so8204248pfc.7 for ; Mon, 08 Apr 2019 12:35:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=dnfaLDhWKK+bdxMDnKDSQrkA21nT3L/ZGr97EYstUIc=; b=vCOXEuCTPmUd5JPK4pHqnAWa90OJx2D+pkBFLkDayUEwb1S/lqnLN65jxDGKZWBo/L dRWstS/QnY+dUE4SLU0OUypT36YkYUSKOKd0j0MCUam5TH9H8lvbGYvvihLpzBk70WdC YlBIY2kjlxz8PxTirdvgeJsYLbU3zU2Lq6Q1o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=dnfaLDhWKK+bdxMDnKDSQrkA21nT3L/ZGr97EYstUIc=; b=HpSI6DLHh9Sbp7qQh7aEBk4SlQyZKYQbJkIxMEupzUEd6PhsVTJL35nkZyP0i9ORmu E0j2vozJpPZYHBaBQQXCuQzEBylEVicO9k7lof7okaMGeshFv2NjR2TQfClsKSX1Q7PN zqiBr8EMxUsLGiKYe82Kr/L5F6vLLpBKmXZX6AGNq2Xd/ekuZaRdiGPK0NUHh/yQaTH+ 2UZnXey/6FARfyCJLcdI4EVIh4XLRsFT1UPcyexE2RT64+K+ixYYa5/ftmHkJno88vna VAOaMFnEWH6fYOBViPr55BX+o/DsZmFhgkR7hKMbuE1MO++DPadVQl01uGOw7va+SHjU D4jg== X-Gm-Message-State: APjAAAWhIbDEL48Wy7cjQDHeVuvvN04p4ny8wLPXQe2fHHE4TV6iMlDo f+JPsdWyZtrGNnUblqOdIR/Llg== X-Google-Smtp-Source: APXvYqxmkHzinTo/c/u+lH4QuYyfczDmi5t38CExfctIY1jBdFusT+T0AzPxDlCQl+ytU9s/4r8b8g== X-Received: by 2002:a63:2c3:: with SMTP id 186mr29393444pgc.161.1554752116264; Mon, 08 Apr 2019 12:35:16 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id f7sm56408835pga.56.2019.04.08.12.35.14 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 08 Apr 2019 12:35:15 -0700 (PDT) Date: Mon, 8 Apr 2019 15:35:14 -0400 From: Joel Fernandes To: Mathieu Desnoyers Cc: paulmck , Rong Chen , linux-kernel , LKP Subject: Re: [srcu] a365bb5f6e: leaking_addresses.proc.___srcu_struct_ptrs. Message-ID: <20190408193514.GD133872@google.com> References: <20190408135610.GN11264@shao2-debian> <20190408143037.GL14111@linux.ibm.com> <20190408145750.GO11264@shao2-debian> <20190408152112.GM14111@linux.ibm.com> <118257214.1376.1554743216233.JavaMail.zimbra@efficios.com> <20190408171041.GQ14111@linux.ibm.com> <1930819602.1467.1554744349263.JavaMail.zimbra@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1930819602.1467.1554744349263.JavaMail.zimbra@efficios.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 08, 2019 at 01:25:49PM -0400, Mathieu Desnoyers wrote: > ----- On Apr 8, 2019, at 1:10 PM, paulmck paulmck@linux.ibm.com wrote: > > > On Mon, Apr 08, 2019 at 01:06:56PM -0400, Mathieu Desnoyers wrote: > >> ----- On Apr 8, 2019, at 11:21 AM, paulmck paulmck@linux.ibm.com wrote: > >> > >> > On Mon, Apr 08, 2019 at 10:57:50PM +0800, Rong Chen wrote: > >> >> On Mon, Apr 08, 2019 at 07:30:37AM -0700, Paul E. McKenney wrote: > >> >> > On Mon, Apr 08, 2019 at 09:56:10PM +0800, kernel test robot wrote: > >> >> > > FYI, we noticed the following commit (built with gcc-7): > >> >> > > > >> >> > > commit: a365bb5f6eafb220a1448674054b05c250829313 ("srcu: Allocate per-CPU data > >> >> > > for DEFINE_SRCU() in modules") > >> >> > > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git > >> >> > > tmp.2019.04.07a > >> >> > > > >> >> > > in testcase: leaking_addresses > >> >> > > with following parameters: > >> >> > > > >> >> > > > >> >> > > > >> >> > > > >> >> > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 2G > >> >> > > > >> >> > > caused below changes (please refer to attached dmesg/kmsg for entire > >> >> > > log/backtrace): > >> >> > > > >> >> > > > >> >> > > +-------------------------------------------------+------------+------------+ > >> >> > > | | a44a55abae | a365bb5f6e | > >> >> > > +-------------------------------------------------+------------+------------+ > >> >> > > | boot_successes | 0 | 3 | > >> >> > > | boot_failures | 4 | 6 | > >> >> > > | BUG:kernel_reboot-without-warning_in_test_stage | 4 | 6 | > >> >> > > | leaking_addresses.proc.___srcu_struct_ptrs. | 0 | 6 | > >> >> > > +-------------------------------------------------+------------+------------+ > >> >> > > >> >> > Please help me out here. Without this commit, the kernel never succeeds > >> >> > in booting, but with it the kernel sometimes succeeds in booting? Or am > >> >> > I misinterpreting the above table? > >> >> > > >> >> > Thanx, Paul > >> >> > >> >> Hi Paul, > >> >> > >> >> The message "kernel_reboot-without-warning_in_test_stage" is from 0day, > >> >> leaking addresses generated many dmesgs, so 0day thought some bootings may > >> >> failed. > >> > > >> [...] > >> >> > > >> >> > > [1 .rodata.cst16.POLY] 0xffffffffc0498360 > >> >> > > [1 .rodata.cst32.byteshift_table] 0xffffffffc03f50f0 > >> >> > > [19 __bug_table] 0xffffffffc02be184 > >> >> > > [2 __tracepoints_ptrs] 0xffffffffc02f1cd0 > >> >> > > [15 .smp_locks] 0xffffffffc042b2cc > >> >> > > [1 .rodata.cst16.enc] 0xffffffffc0498420 > >> >> > > [11 __ksymtab_gpl] 0xffffffffc042b028 > >> >> > > [8 __ex_table] 0xffffffffc04f13f4 > >> >> > > [1 .init.rodata] 0xffffffffc0316000 > >> >> > > [36 .note.gnu.build-id] 0xffffffffc03ed000 > >> >> > > [1 .rodata.cst16.dec] 0xffffffffc0498410 > >> >> > > [16 .parainstructions] 0xffffffffc03ed940 > >> >> > > [8 .text..refcount] 0xffffffffc04e2aaa > >> >> > > [36 .gnu.linkonce.this_module] 0xffffffffc03f12c0 > >> >> > > [2 __bpf_raw_tp_map] 0xffffffffc03054a0 > >> >> > > [30 .orc_unwind_ip] 0xffffffffc03ee9f9 > >> >> > > [8 .altinstr_replacement] 0xffffffffc0497372 > >> >> > > [26 .rodata.str1.8] 0xffffffffc03ed1f0 > >> >> > > [11 __verbose] 0xffffffffc05c9398 > >> >> > > [1 .rodata.cst16.TWOONE] 0xffffffffc0498380 > >> >> > > [1 uevent] KEY=402000000 3803078f800d001 feffffdfffefffff fffffffffffffffe > >> >> > > [1 .rodata.cst16.ONE] 0xffffffffc04983e0 > >> >> > > [8 .altinstructions] 0xffffffffc0498430 > >> >> > > [36 modules] crct10dif_pclmul 16384 1 - Live 0xffffffffc03f4000 > >> >> > > [1 ___srcu_struct_ptrs] 0xffffffffc03840d0 > >> >> > > > >> > >> This list of "leaked" memory seems to include the __tracepoint_ptrs > >> as well. So at least you seem to have the same behavior as the tracepoint > >> code, which was your source of inspiration for this implementation, > >> which is a good start. > >> > >> So the remaining question is: is this memory allocated for module sections > >> really leaked for each module, or is it an issue with memory allocation > >> tracking ? > > It looks to me like this has nothing to do with memory allocation. This is the leaking_addresses.pl script isn't it? It basically finds out if any /proc filesystem entries or dmesg lines have kernel addresses which could be "leaking" into userspace. I have no idea which filesystem entries leak these addresses. This commit that introduced the script is: commit 136fc5c41f349296db1910677bb7402b0eeff376 Author: Tobin C. Harding Date: Mon Nov 6 16:19:27 2017 +1100 scripts: add leaking_addresses.pl Currently we are leaking addresses from the kernel to user space. This script is an attempt to find some of those leakages. Script parses `dmesg` output and /proc and /sys files for hex strings that look like kernel addresses. thanks, - Joel