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[2620:137:e000::1:20]) by mx.google.com with ESMTP id u21-20020a05640207d500b0051e0299f0f5si6316762edy.475.2023.07.24.02.49.12; Mon, 24 Jul 2023 02:49:38 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbjGXJiZ (ORCPT + 99 others); Mon, 24 Jul 2023 05:38:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbjGXJiY (ORCPT ); Mon, 24 Jul 2023 05:38:24 -0400 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BD7C1A1; Mon, 24 Jul 2023 02:38:23 -0700 (PDT) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qNs1C-0005Vz-5L; Mon, 24 Jul 2023 11:38:18 +0200 Message-ID: Date: Mon, 24 Jul 2023 11:38:17 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data Content-Language: en-US, de-DE To: Jiri Olsa , Lorenzo Stoakes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Baoquan He , Uladzislau Rezki , Matthew Wilcox , David Hildenbrand , Liu Shixin , Jens Axboe , Alexander Viro , Linux kernel regressions list References: From: "Linux regression tracking (Thorsten Leemhuis)" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1690191503;cd776fae; X-HE-SMSGID: 1qNs1C-0005Vz-5L X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [CCing the regression list, as it should be in the loop for regressions: https://docs.kernel.org/admin-guide/reporting-regressions.html] [TLDR: I'm adding this report to the list of tracked Linux kernel regressions; the text you find below is based on a few templates paragraphs you might have encountered already in similar form. See link in footer if these mails annoy you.] On 31.05.23 13:58, Jiri Olsa wrote: > On Thu, Mar 23, 2023 at 10:15:16AM +0000, Lorenzo Stoakes wrote: >> Commit df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") >> introduced the use of a bounce buffer to retrieve kernel text data for >> /proc/kcore in order to avoid failures arising from hardened user copies >> enabled by CONFIG_HARDENED_USERCOPY in check_kernel_text_object(). >> [...] >> Signed-off-by: Lorenzo Stoakes >> Reviewed-by: David Hildenbrand > > sorry for late feedback, but looks like this one breaks reading > /proc/kcore with objdump for me: > > # cat /proc/kallsyms | grep ksys_read > ffffffff8150ebc0 T ksys_read > # objdump -d --start-address=0xffffffff8150ebc0 --stop-address=0xffffffff8150ebd0 /proc/kcore > > /proc/kcore: file format elf64-x86-64 > > objdump: Reading section load1 failed because: Bad address > > reverting this makes it work again Thanks for the report. To be sure the issue doesn't fall through the cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression tracking bot: #regzbot ^introduced 2e1c017077 #regzbot title mm / fs/proc/kcore: reading /proc/kcore with objdump broke #regzbot ignore-activity This isn't a regression? This issue or a fix for it are already discussed somewhere else? It was fixed already? You want to clarify when the regression started to happen? Or point out I got the title or something else totally wrong? Then just reply and tell me -- ideally while also telling regzbot about it, as explained by the page listed in the footer of this mail. Developers: When fixing the issue, remember to add 'Link:' tags pointing to the report (the parent of this mail). See page linked in footer for details. Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr That page also explains what to do if mails like this annoy you.