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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B9C6C021AA for ; Wed, 19 Feb 2025 10:59:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0A771440159; Wed, 19 Feb 2025 05:59:13 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 05444440156; Wed, 19 Feb 2025 05:59:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E36D2440159; Wed, 19 Feb 2025 05:59:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id BFD56440156 for ; Wed, 19 Feb 2025 05:59:12 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 3D9BEA35B9 for ; Wed, 19 Feb 2025 10:59:12 +0000 (UTC) X-FDA: 83136397344.15.B0004C4 Received: from mail-lf1-f48.google.com (mail-lf1-f48.google.com [209.85.167.48]) by imf11.hostedemail.com (Postfix) with ESMTP id 0BB2D4000F for ; Wed, 19 Feb 2025 10:59:09 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=easyb-ch.20230601.gappssmtp.com header.s=20230601 header.b=YNvDPfhw; spf=none (imf11.hostedemail.com: domain of ezra@easyb.ch has no SPF policy when checking 209.85.167.48) smtp.mailfrom=ezra@easyb.ch; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739962750; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=TvUqBXo7pX3OGufaHCVvGrqItUXzyJoYQX0buW7FGwM=; b=3lyZzQy/mmEH7IeI3HXXl8ZfroLsijgNyJ4xrv7hM4RIb2UhWLssjG2FZ4az4MygJtWxhM yCZkBruj2B5+zHVJMW6PbzYvt2KKxyutviONND++Kgft8tYDhQ6ljjFHcfcWbCQU3xvTC9 fV9epUgR+5847+qaaFP0k/tQov5wW90= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=easyb-ch.20230601.gappssmtp.com header.s=20230601 header.b=YNvDPfhw; spf=none (imf11.hostedemail.com: domain of ezra@easyb.ch has no SPF policy when checking 209.85.167.48) smtp.mailfrom=ezra@easyb.ch; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739962750; a=rsa-sha256; cv=none; b=yhyqCGjwdeFNtSSaxJBenR1pSndVTvkSPGLExJvgZb9RqNsVfhHUOhnMoc8wKCfZ/mA5/l IycmGfLifXVlA1rjSw0P5Xw0u0Nboqk01GB0K+HTTqa+E481EUVmHOUFzYD9HuqBOOiT0S b4e+L6bchhVn2gB4QEzPRZIBJlvnEhI= Received: by mail-lf1-f48.google.com with SMTP id 2adb3069b0e04-5452c1daabeso4239016e87.1 for ; Wed, 19 Feb 2025 02:59:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=easyb-ch.20230601.gappssmtp.com; s=20230601; t=1739962748; x=1740567548; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=TvUqBXo7pX3OGufaHCVvGrqItUXzyJoYQX0buW7FGwM=; b=YNvDPfhwQV829K8l65WypeqSGktjixX57EI+GVtMOjovuSwqZdQA2kT8EW9y8wLrW8 ael3SVWgmHm/F8S0jGyv2I+zFAY/iTOfKS6X7mkwVaxIGf9CwFIHAsl83hRBjZZ97lLD 0DePsxx9/5aVf1hep3tUuLliPBUjRgnngiWkY99oTnP8YT7c71gxv02Si/i1GjRlGByr 8WOZnmspUeIPmzMR3wZjIRbexNWcwNm6TA4xIE2DFpe6hChZ0msVIeDdIPOAQYoJh3YB Z1hPKt/M2QAUcAlqf+fmm+W4FyQXWFxpAvoUxdV6BKM/IOD6mP1uDw1xIHgONfQi6JfI o5DA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739962748; x=1740567548; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TvUqBXo7pX3OGufaHCVvGrqItUXzyJoYQX0buW7FGwM=; b=buHq6KGM6Ys0dnz36aAwutuGkWxStPJcbsXrzxZr1tlqf0r8j5tXvQckHUQpNrvGg9 SJE8+0aDv2PQzAjob1hGHHidD4/iU/7wKMEBYbLi7EnWVW5dnsJj68RnrPtUL7rvo6R7 CT8dWQ5gIsmeZvAUFnAGSNvTJ+b5LCyGM+tqM6BP0wO5kcT/YXXPmU0lyBkI8yTFr5ve r8TODOihrGAWpB16d1+BBbYtUrn4x49XNBIZ7kFxMPX6+pnPiHHRYJgfQxix9AycfV2R vXjQV+tdtL/kbRDEV+CG17F7XHEN95V0W/x2WM+rmy2oYqmu5YyMHVO4fdGTHl20UpNZ Z7Wg== X-Forwarded-Encrypted: i=1; AJvYcCWKfgbtwULnNDc+2tH1yHNvDFBjJ9fEQumYyUGD2rzI3ndnxX/A+YexIpBaHm+tRH3GG6EFMrupmA==@kvack.org X-Gm-Message-State: AOJu0Yw28DSansD8bARfAkCPMXy13VaRGP9TZCbFQEoCXaPxmEVgLm0F NJQ2CFQCCT/T+fnFIYzeXosg+SX0nIlAYNyR1ZbvWPzvWIsoIlrCgbmyrqMYiUCuZtxtL4iDNaw /gGyMM4i+p6LAgLdjgd4uDHYMKKkiIU6IeI1ZOg== X-Gm-Gg: ASbGncsK6oTmEqj5iDMVnEqkZtA4ECNccdyv1S/NQZ+Pd9fohyQh4biuVXOiEtT3wAR mYFRFkCDJItYdGXzReupYBiZFCY16ypQL2K2yVSkZRZg/YFf/EMo47TSe2vX/8DJsV6RpobnkDK yfJ+tKwMlm/4RBieqGj45PoNirnQ== X-Google-Smtp-Source: AGHT+IFDf2xMI1aCLfZeNkHbqTc1fxdjKU8LMLIa3hxyXKQN16RxmxbrXD8qMf75n+E2fkiXk1K0zktwSDgaBlo61MM= X-Received: by 2002:a05:6512:158b:b0:545:2cb6:af31 with SMTP id 2adb3069b0e04-5452fe426cdmr6409842e87.15.1739962747645; Wed, 19 Feb 2025 02:59:07 -0800 (PST) MIME-Version: 1.0 References: <20250217024924.57996-1-zhengqi.arch@bytedance.com> In-Reply-To: <20250217024924.57996-1-zhengqi.arch@bytedance.com> From: Ezra Buehler Date: Wed, 19 Feb 2025 11:58:31 +0100 X-Gm-Features: AWEUYZlJLxDsFiFpyrhpbMagLjwKnctzA_YuuA29jDCzt3ZkPaZaHYpVKVWkXxU Message-ID: Subject: Re: [PATCH v3] arm: pgtable: fix NULL pointer dereference issue To: Qi Zheng Cc: linux@armlinux.org.uk, david@redhat.com, hughd@google.com, ryan.roberts@arm.com, akpm@linux-foundation.org, muchun.song@linux.dev, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ezra Buehler , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0BB2D4000F X-Stat-Signature: t4cngyei9tnz4d8etegpnwwwhx6f5cim X-HE-Tag: 1739962749-504323 X-HE-Meta: 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 I7AXeldH 6RXuwNyfho8Awzl38thjyKlElw1pR7kOP/yGKsJh19CC81LAV6AbrUg+JMDlWDqPJUeZ35U1iiAqq+MUEdVFzxF0LF/FlQwIojusJgYwfEKIwvQMsL8mVRQTaOmpovsaz/gVFSU45z25KJoTPETAI7CauaWqgiIju4w6/u+oMtH1cKodk/GK7FLP8ahoySg6hajmu2vpw7NDFSRQY/UOZ+QrXQfHqw42NdmJsVoM/aTMRvc9lyVGkY/lVeGzmrfqtO3GsZu5FdE6QcwRxfhaG5FaGUOXadKeQY7DNwOuCxW3U1nnD5gbMQ4RRQY/nTc9qxF/uYraT/Pnm5c3oiYadVhrnu7XEC3/B1fDT8MmiSHeHuF0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.001754, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Feb 17, 2025 at 3:49=E2=80=AFAM Qi Zheng wrote: > > When update_mmu_cache_range() is called by update_mmu_cache(), the vmf > parameter is NULL, which will cause a NULL pointer dereference issue in > adjust_pte(): > > Unable to handle kernel NULL pointer dereference at virtual address 00000= 030 when read > Hardware name: Atmel AT91SAM9 > PC is at update_mmu_cache_range+0x1e0/0x278 > LR is at pte_offset_map_rw_nolock+0x18/0x2c > Call trace: > update_mmu_cache_range from remove_migration_pte+0x29c/0x2ec > remove_migration_pte from rmap_walk_file+0xcc/0x130 > rmap_walk_file from remove_migration_ptes+0x90/0xa4 > remove_migration_ptes from migrate_pages_batch+0x6d4/0x858 > migrate_pages_batch from migrate_pages+0x188/0x488 > migrate_pages from compact_zone+0x56c/0x954 > compact_zone from compact_node+0x90/0xf0 > compact_node from kcompactd+0x1d4/0x204 > kcompactd from kthread+0x120/0x12c > kthread from ret_from_fork+0x14/0x38 > Exception stack(0xc0d8bfb0 to 0xc0d8bff8) > > To fix it, do not rely on whether 'ptl' is equal to decide whether to hol= d > the pte lock, but decide it by whether CONFIG_SPLIT_PTE_PTLOCKS is > enabled. In addition, if two vmas map to the same PTE page, there is no > need to hold the pte lock again, otherwise a deadlock will occur. Just ad= d > the need_lock parameter to let adjust_pte() know this information. > > Reported-by: Ezra Buehler > Closes: https://lore.kernel.org/lkml/CAM1KZSmZ2T_riHvay+7cKEFxoPgeVpHkVFT= zVVEQ1BO0cLkHEQ@mail.gmail.com/ > Fixes: fc9c45b71f43 ("arm: adjust_pte() use pte_offset_map_rw_nolock()") > Cc: stable@vger.kernel.org > Signed-off-by: Qi Zheng > Acked-by: David Hildenbrand Tested-by: Ezra Buehler I confirm that this fixes our issue on the AT91SAM9G25-based GARDENA smart Gateway. However, unfortunately, I do not have a 4-core ARMv5 board at hand to test the CONFIG_SPLIT_PTE_PTLOCKS case. Cheers, Ezra.