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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 43C8DC433E9 for ; Tue, 2 Mar 2021 09:49:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 088A864EFC for ; Tue, 2 Mar 2021 09:49:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382670AbhCBJku (ORCPT ); Tue, 2 Mar 2021 04:40:50 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:16247 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1838108AbhCBJ2V (ORCPT ); Tue, 2 Mar 2021 04:28:21 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DqWxh65Czz9vBLF; Tue, 2 Mar 2021 10:27:36 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id D2UnChWDqhR1; Tue, 2 Mar 2021 10:27:36 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4DqWxh58jrz9vBLD; Tue, 2 Mar 2021 10:27:36 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id CDBF28B75F; Tue, 2 Mar 2021 10:27:37 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id nNec12v5Mb1w; Tue, 2 Mar 2021 10:27:37 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 310CF8B7AD; Tue, 2 Mar 2021 10:27:37 +0100 (CET) Subject: Re: [RFC PATCH v1] powerpc: Enable KFENCE for PPC32 To: Alexander Potapenko Cc: Marco Elver , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Dmitry Vyukov , LKML , linuxppc-dev@lists.ozlabs.org, kasan-dev References: <51c397a23631d8bb2e2a6515c63440d88bf74afd.1614674144.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Message-ID: Date: Tue, 2 Mar 2021 10:27:35 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 02/03/2021 à 10:21, Alexander Potapenko a écrit : >> [ 14.998426] BUG: KFENCE: invalid read in finish_task_switch.isra.0+0x54/0x23c >> [ 14.998426] >> [ 15.007061] Invalid read at 0x(ptrval): >> [ 15.010906] finish_task_switch.isra.0+0x54/0x23c >> [ 15.015633] kunit_try_run_case+0x5c/0xd0 >> [ 15.019682] kunit_generic_run_threadfn_adapter+0x24/0x30 >> [ 15.025099] kthread+0x15c/0x174 >> [ 15.028359] ret_from_kernel_thread+0x14/0x1c >> [ 15.032747] >> [ 15.034251] CPU: 0 PID: 111 Comm: kunit_try_catch Tainted: G B >> 5.12.0-rc1-s3k-dev-01534-g4f14ae75edf0-dirty #4674 >> [ 15.045811] ================================================================== >> [ 15.053324] # test_invalid_access: EXPECTATION FAILED at mm/kfence/kfence_test.c:636 >> [ 15.053324] Expected report_matches(&expect) to be true, but is false >> [ 15.068359] not ok 21 - test_invalid_access > > The test expects the function name to be test_invalid_access, i. e. > the first line should be "BUG: KFENCE: invalid read in > test_invalid_access". > The error reporting function unwinds the stack, skips a couple of > "uninteresting" frames > (https://elixir.bootlin.com/linux/v5.12-rc1/source/mm/kfence/report.c#L43) > and uses the first "interesting" one frame to print the report header > (https://elixir.bootlin.com/linux/v5.12-rc1/source/mm/kfence/report.c#L226). > > It's strange that test_invalid_access is missing altogether from the > stack trace - is that expected? > Can you try printing the whole stacktrace without skipping any frames > to see if that function is there? > Booting with 'no_hash_pointers" I get the following. Does it helps ? [ 16.837198] ================================================================== [ 16.848521] BUG: KFENCE: invalid read in finish_task_switch.isra.0+0x54/0x23c [ 16.848521] [ 16.857158] Invalid read at 0xdf98800a: [ 16.861004] finish_task_switch.isra.0+0x54/0x23c [ 16.865731] kunit_try_run_case+0x5c/0xd0 [ 16.869780] kunit_generic_run_threadfn_adapter+0x24/0x30 [ 16.875199] kthread+0x15c/0x174 [ 16.878460] ret_from_kernel_thread+0x14/0x1c [ 16.882847] [ 16.884351] CPU: 0 PID: 111 Comm: kunit_try_catch Tainted: G B 5.12.0-rc1-s3k-dev-01534-g4f14ae75edf0-dirty #4674 [ 16.895908] NIP: c016eb8c LR: c02f50dc CTR: c016eb38 [ 16.900963] REGS: e2449d90 TRAP: 0301 Tainted: G B (5.12.0-rc1-s3k-dev-01534-g4f14ae75edf0-dirty) [ 16.911386] MSR: 00009032 CR: 22000004 XER: 00000000 [ 16.918153] DAR: df98800a DSISR: 20000000 [ 16.918153] GPR00: c02f50dc e2449e50 c1140d00 e100dd24 c084b13c 00000008 c084b32b c016eb38 [ 16.918153] GPR08: c0850000 df988000 c0d10000 e2449eb0 22000288 [ 16.936695] NIP [c016eb8c] test_invalid_access+0x54/0x108 [ 16.942125] LR [c02f50dc] kunit_try_run_case+0x5c/0xd0 [ 16.947292] Call Trace: [ 16.949746] [e2449e50] [c005a5ec] finish_task_switch.isra.0+0x54/0x23c (unreliable) [ 16.957443] [e2449eb0] [c02f50dc] kunit_try_run_case+0x5c/0xd0 [ 16.963319] [e2449ed0] [c02f63ec] kunit_generic_run_threadfn_adapter+0x24/0x30 [ 16.970574] [e2449ef0] [c004e710] kthread+0x15c/0x174 [ 16.975670] [e2449f30] [c001317c] ret_from_kernel_thread+0x14/0x1c [ 16.981896] Instruction dump: [ 16.984879] 8129d608 38e7eb38 81020280 911f004c 39000000 995f0024 907f0028 90ff001c [ 16.992710] 3949000a 915f0020 3d40c0d1 3d00c085 <8929000a> 3908adb0 812a4b98 3d40c02f [ 17.000711] ================================================================== [ 17.008223] # test_invalid_access: EXPECTATION FAILED at mm/kfence/kfence_test.c:636 [ 17.008223] Expected report_matches(&expect) to be true, but is false [ 17.023243] not ok 21 - test_invalid_access