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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 87A00C2BA19 for ; Tue, 14 Apr 2020 09:17:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 24A4D206E9 for ; Tue, 14 Apr 2020 09:17:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="spfabpwV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24A4D206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=web.de Authentication-Results: mail.kernel.org; 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Tue, 14 Apr 2020 09:17:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1586855838; bh=6697LzT05QB2vWxGR2+6HHm5Jxfu/XK6SRemGQs3IPs=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=spfabpwVT+s7KhhXJzgQMphV9zmr8X3dPlt54mOSCMxG8JZ9DKiMz7un9HJYUQJU4 dgDJYw/YrI8b1RsgMbuGIwaI8g63HDsuqm/akq9JHYpl2MnjwvyxvESCjgg2ZylnOE EZrKdu7kNXjeZxM/BWShdR6KEOqcT9CVG1HTDui0= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.3] ([78.49.66.171]) by smtp.web.de (mrweb102 [213.165.67.124]) with ESMTPSA (Nemesis) id 0MPYNR-1jJaj122fh-004jsY; Tue, 14 Apr 2020 11:17:18 +0200 Subject: Re: [PATCH v2] mm/ksm: Fix NULL pointer dereference when KSM zero page is enabled To: Muchun Song , Xiongchun Duan , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Andrew Morton References: <20200414075622.69822-1-songmuchun@bytedance.com> From: Markus Elfring Autocrypt: addr=Markus.Elfring@web.de; prefer-encrypt=mutual; keydata= mQINBFg2+xABEADBJW2hoUoFXVFWTeKbqqif8VjszdMkriilx90WB5c0ddWQX14h6w5bT/A8 +v43YoGpDNyhgA0w9CEhuwfZrE91GocMtjLO67TAc2i2nxMc/FJRDI0OemO4VJ9RwID6ltwt mpVJgXGKkNJ1ey+QOXouzlErVvE2fRh+KXXN1Q7fSmTJlAW9XJYHS3BDHb0uRpymRSX3O+E2 lA87C7R8qAigPDZi6Z7UmwIA83ZMKXQ5stA0lhPyYgQcM7fh7V4ZYhnR0I5/qkUoxKpqaYLp YHBczVP+Zx/zHOM0KQphOMbU7X3c1pmMruoe6ti9uZzqZSLsF+NKXFEPBS665tQr66HJvZvY GMDlntZFAZ6xQvCC1r3MGoxEC1tuEa24vPCC9RZ9wk2sY5Csbva0WwYv3WKRZZBv8eIhGMxs rcpeGShRFyZ/0BYO53wZAPV1pEhGLLxd8eLN/nEWjJE0ejakPC1H/mt5F+yQBJAzz9JzbToU 5jKLu0SugNI18MspJut8AiA1M44CIWrNHXvWsQ+nnBKHDHHYZu7MoXlOmB32ndsfPthR3GSv jN7YD4Ad724H8fhRijmC1+RpuSce7w2JLj5cYj4MlccmNb8YUxsE8brY2WkXQYS8Ivse39MX BE66MQN0r5DQ6oqgoJ4gHIVBUv/ZwgcmUNS5gQkNCFA0dWXznQARAQABtCZNYXJrdXMgRWxm cmluZyA8TWFya3VzLkVsZnJpbmdAd2ViLmRlPokCVAQTAQgAPhYhBHDP0hzibeXjwQ/ITuU9 Figxg9azBQJYNvsQAhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEOU9Figx g9azcyMP/iVihZkZ4VyH3/wlV3nRiXvSreqg+pGPI3c8J6DjP9zvz7QHN35zWM++1yNek7Ar OVXwuKBo18ASlYzZPTFJZwQQdkZSV+atwIzG3US50ZZ4p7VyUuDuQQVVqFlaf6qZOkwHSnk+ CeGxlDz1POSHY17VbJG2CzPuqMfgBtqIU1dODFLpFq4oIAwEOG6fxRa59qbsTLXxyw+PzRaR LIjVOit28raM83Efk07JKow8URb4u1n7k9RGAcnsM5/WMLRbDYjWTx0lJ2WO9zYwPgRykhn2 sOyJVXk9xVESGTwEPbTtfHM+4x0n0gC6GzfTMvwvZ9G6xoM0S4/+lgbaaa9t5tT/PrsvJiob kfqDrPbmSwr2G5mHnSM9M7B+w8odjmQFOwAjfcxoVIHxC4Cl/GAAKsX3KNKTspCHR0Yag78w i8duH/eEd4tB8twcqCi3aCgWoIrhjNS0myusmuA89kAWFFW5z26qNCOefovCx8drdMXQfMYv g5lRk821ZCNBosfRUvcMXoY6lTwHLIDrEfkJQtjxfdTlWQdwr0mM5ye7vd83AManSQwutgpI q+wE8CNY2VN9xAlE7OhcmWXlnAw3MJLW863SXdGlnkA3N+U4BoKQSIToGuXARQ14IMNvfeKX NphLPpUUnUNdfxAHu/S3tPTc/E/oePbHo794dnEm57LuuQINBFg2+xABEADZg/T+4o5qj4cw nd0G5pFy7ACxk28mSrLuva9tyzqPgRZ2bdPiwNXJUvBg1es2u81urekeUvGvnERB/TKekp25 4wU3I2lEhIXj5NVdLc6eU5czZQs4YEZbu1U5iqhhZmKhlLrhLlZv2whLOXRlLwi4jAzXIZAu 76mT813jbczl2dwxFxcT8XRzk9+dwzNTdOg75683uinMgskiiul+dzd6sumdOhRZR7YBT+xC wzfykOgBKnzfFscMwKR0iuHNB+VdEnZw80XGZi4N1ku81DHxmo2HG3icg7CwO1ih2jx8ik0r riIyMhJrTXgR1hF6kQnX7p2mXe6K0s8tQFK0ZZmYpZuGYYsV05OvU8yqrRVL/GYvy4Xgplm3 DuMuC7/A9/BfmxZVEPAS1gW6QQ8vSO4zf60zREKoSNYeiv+tURM2KOEj8tCMZN3k3sNASfoG fMvTvOjT0yzMbJsI1jwLwy5uA2JVdSLoWzBD8awZ2X/eCU9YDZeGuWmxzIHvkuMj8FfX8cK/ 2m437UA877eqmcgiEy/3B7XeHUipOL83gjfq4ETzVmxVswkVvZvR6j2blQVr+MhCZPq83Ota xNB7QptPxJuNRZ49gtT6uQkyGI+2daXqkj/Mot5tKxNKtM1Vbr/3b+AEMA7qLz7QjhgGJcie qp4b0gELjY1Oe9dBAXMiDwARAQABiQI8BBgBCAAmFiEEcM/SHOJt5ePBD8hO5T0WKDGD1rMF Alg2+xACGwwFCQlmAYAACgkQ5T0WKDGD1rOYSw/+P6fYSZjTJDAl9XNfXRjRRyJSfaw6N1pA Ahuu0MIa3djFRuFCrAHUaaFZf5V2iW5xhGnrhDwE1Ksf7tlstSne/G0a+Ef7vhUyeTn6U/0m +/BrsCsBUXhqeNuraGUtaleatQijXfuemUwgB+mE3B0SobE601XLo6MYIhPh8MG32MKO5kOY hB5jzyor7WoN3ETVNQoGgMzPVWIRElwpcXr+yGoTLAOpG7nkAUBBj9n9TPpSdt/npfok9ZfL /Q+ranrxb2Cy4tvOPxeVfR58XveX85ICrW9VHPVq9sJf/a24bMm6+qEg1V/G7u/AM3fM8U2m tdrTqOrfxklZ7beppGKzC1/WLrcr072vrdiN0icyOHQlfWmaPv0pUnW3AwtiMYngT96BevfA qlwaymjPTvH+cTXScnbydfOQW8220JQwykUe+sHRZfAF5TS2YCkQvsyf7vIpSqo/ttDk4+xc Z/wsLiWTgKlih2QYULvW61XU+mWsK8+ZlYUrRMpkauN4CJ5yTpvp+Orcz5KixHQmc5tbkLWf x0n1QFc1xxJhbzN+r9djSGGN/5IBDfUqSANC8cWzHpWaHmSuU3JSAMB/N+yQjIad2ztTckZY pwT6oxng29LzZspTYUEzMz3wK2jQHw+U66qBFk8whA7B2uAU1QdGyPgahLYSOa4XAEGb6wbI FEE= Message-ID: Date: Tue, 14 Apr 2020 11:17:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200414075622.69822-1-songmuchun@bytedance.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Provags-ID: V03:K1:DOkhi4BwKFOQ2s2dM0MhSJSupuY8nYp+WtL7iBe9viUoua5rB2m DTme6jSakZgV2rvhQLtDgJFFdZQtTStkfJ2HfBHk/qjskhrye33n4NhiHp/1j2KdcZ0T4qw e09vJ+WQX5cJtRz9HhHHpDGKoNaPyJqw30DasU4TjEp2gydwnWBNDsGSd0me1kwOQXgTuRl zrCX9N0gwJBqGlLBJy1lQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:J5vTnck+7xo=:PmKQpUcJWrTERWG0ufoe40 P3/6kN1h0gnzf4pUwry4i3zNP1dYTlnbCzch6R6GPuSQ9HV4soGvUjXJ312pjCyCo1bcb+qYQ bZz4FiRPcTsChd487sclIj9/cHqgr18EqLiXcHsobMH0HosdyrQXVQnJ4KARZAGaeVj44kSri dIEWrk2Ca1uACuRlvdx7ucBdtDY3+egEaV9ZX3FKTsT5mhuNIz5aRQH/3GnYUEzh3ySyzNFmd aLY2ox6r5sgQBP9k+6trgqL5KzJ+0PeEbEIYGcKu5ATLK6OhaVS5CjWXKKqiTD0d7+5QE4PIL WKEIOtIyLv1zCA0h/BhXyCNwmSIm1Jb0JeG2Bt5FlvvGc5GkKVmZebpgngPpnUrnPXH2RzsFK Hoq/q3OWH4hY0oE8qzCqgw9V5squgiTVwWeLs0CV8SRQpi3OZDZjI1LeqmlZFIVBYFiFmGU+X R3lSHm3Jh36YjM7UY/ydAwfxuSRpEwFMYjdAcvhjYzslaHKPRRGfq25HJ5Eypnav24jcJYCD7 uq7jNunFlEUByJPl01ftXxvDITEjnJPpqvH5/XHZNz4e2c4ujvS9VQS5fgiXvX3VhSyObI2qB R8GsJ0H7n3o3atQ4JsGmmv2yr/pSb6H19jsqz4dSuLtcte9nmo4ZuX8cS0eapKOqxHLCo9dCB zIL5xjz/tVUBWR02iW/b36Pu5gStG9MS5W2tw6AxhwrRDAaKTyPed6LdHyuOoivnynInEoqJR CdHn7VZxsP/e+JL+yd9Rr+T08JCzv+yTHuvMNMSBBIS9nqRmp5FyV3bevqZ0zcfM0xTUQQO47 SYn7jhBEi+ZfbQdaQk9qzEtrIZY9o4DIlQV9mK1vooQ5eZs53TWJsBximCEAeY52H/7Gi2wQh sOLWZ5audRETpubazU+Z3/HMWnJF2wxQcmAufSKunAJRf3ftjYRrjNRfUnbW5O1mlijfJlBYz DTnXGsYuIYjnxBBqregRgfIbjEwIsLZ7eY658XHDQgBo8E6WBmpXwgpWqhOQjHaVMhGMIiFbQ hHE8E7ta00waXhLuCppUY+sgNqaJ4xsdnDeb24z4sha02XXPa2G0jOpJVE/8lAo/4RIIhPtZ9 YmQ8Cs3ayBJJIaPSjqdjpkufeOACocOM1+uLT4hbX7KXKI+5YDoHwOKDDWpn4qXotBF33GIIi PWzGZ4xt0/5iSBbRlzr7rWhNQg6nePuJdj+pWr3e+iAPdgz490IVINc/WpC0c4pnhuw2sLLB1 +HeEti9Gkk2l6ladd X-Bogosity: Ham, tests=bogofilter, spamicity=0.026963, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > to crash when we access vma->vm_mm(its offset is 0x40) later in Will another fine-tuning become relevant also for this wording? > following calltrace is captured in kernel 4.19 with KSM zero page Can the mentioned Linux version trigger any special software development concerns? Will any other tags become helpful in such a case? Regards, Markus