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 E15E5D6C287 for ; Tue, 19 Nov 2024 19:30:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5645C6B0083; Tue, 19 Nov 2024 14:30:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 513F06B0088; Tue, 19 Nov 2024 14:30:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3DCA06B0089; Tue, 19 Nov 2024 14:30:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 1D4EA6B0083 for ; Tue, 19 Nov 2024 14:30:52 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 436CEA036B for ; Tue, 19 Nov 2024 19:30:51 +0000 (UTC) X-FDA: 82803835464.21.6417434 Received: from mail-yb1-f180.google.com (mail-yb1-f180.google.com [209.85.219.180]) by imf20.hostedemail.com (Postfix) with ESMTP id 2C0FB1C0005 for ; Tue, 19 Nov 2024 19:29:45 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=soleen-com.20230601.gappssmtp.com header.s=20230601 header.b=B6WJMYQc; dmarc=pass (policy=none) header.from=soleen.com; spf=pass (imf20.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.219.180 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1732044558; 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=ErTS0IiytaK2L1arGFQ99J+dEynjCDrSs7AnKL0EeSI=; b=uOr/PNfE1kLZXRgq13/bb8ro2XeKWTg9Xp/ElTaA2ws+C+r+QVOZyduLx64DhIisQ1CNeq NIaE/lQOILgrUAhBsv79qDLnKAj7Nplmexnt9MI9x/GOe3Q1OQ9B83EVyopo/s3lPHgnQI jCLu8quf96HjzoO1euEQFBIZ90HV+1E= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=soleen-com.20230601.gappssmtp.com header.s=20230601 header.b=B6WJMYQc; dmarc=pass (policy=none) header.from=soleen.com; spf=pass (imf20.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.219.180 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1732044558; a=rsa-sha256; cv=none; b=X/+MblMUp4KmmZpvhFHT3npTuvLSClQEuzJ6RGra9kLwBxoHwVjkVWqiVAKsdCwuS06W6r kavdu7KgPrLiiE1yBDbDroE6Qmfqeg3BkSu0jORoQg5YZFOsPkt3mBu5tiZwp2NVIIz5yK 9QkCGlCoeenXh7EUmvZ8+kE01Dn2YcI= Received: by mail-yb1-f180.google.com with SMTP id 3f1490d57ef6-e38866c8b2dso2719790276.2 for ; Tue, 19 Nov 2024 11:30:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen-com.20230601.gappssmtp.com; s=20230601; t=1732044648; x=1732649448; 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=ErTS0IiytaK2L1arGFQ99J+dEynjCDrSs7AnKL0EeSI=; b=B6WJMYQceI1cXv5Br471QPIXQaMryxZf2UNZORmxgs3egVxJkoyDrZWSyChnNFEn/o hfe9VDYPSCneGjiTCBPpUJvlMu/maS39lpOHeYjS2LrwfMU8EfXt4XtZ7XHpy3NlZo18 CNprDCpqf8sEU4d3axQORqd6HFs57hAe4a8eUZWownsXGqk8X2Hfq61Av+F5OPUZ2+A9 UlIKPGZibtIHn8IjxvMe8XDZ4V8YHxPnH7G9R2goXTc/db+rtAUJUZrHaNOFJt0siE9n S7/FnYWOCKI0ySJPoWDHqdutgzsP70HK1rcWC+/yM3bZPCkXGgb4iPQvr4ueWmXe59s6 WjBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732044648; x=1732649448; 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=ErTS0IiytaK2L1arGFQ99J+dEynjCDrSs7AnKL0EeSI=; b=HcetwB4e9CX/GdUyxBICDTQTkGHwUFr3SPMZ/7S+at9OCSEMXaH7IYJ1+QVF7lWaF3 nwTXGsRD0L4WsxSZz6YHa7j4rPgBPQp2ESWhQ4yCmDLJESfHVLgvTkQzVrZipv/vbadg 9Ygn9aBdX7V+z7aujyrTG3YQgLyjUoFuG4IlEjAsZFiij4TNfx6DhHbZKBGstGajyEHb llchbvXK22Wp8IpNLppz1jOtMmm/K/a72zRgu/rTbhzenCsmrYc/dWdjq3tc7w1h7tWL +zRSRW6AxyoyuvAW0qvQlE+M0mr8BMrwvTO34j/OE2TrLPe/7BMxUaw80NKmmVNE2NEG 7cjg== X-Forwarded-Encrypted: i=1; AJvYcCUTxCkxQNAQ4SXvnuoTuM5dhhuBWAJsr9Zw0KCYrDij3/6h+qMuxUE1C9aQOm/Mv14+ZaJ2qX8F0Q==@kvack.org X-Gm-Message-State: AOJu0Yye3AYLJLHcj0Noac2sBfkL6iSXZFD8Z6tEAICR3+3+xRCMdydV r+FeW7EO5uGHOLp8wzDGyrmRn6V4tgXBGkfdfpljiWFQUHXmbvLYuir0PeAQ0eSkUJoVsJQrKKT hAZ9NXRdwsFHnQILebpOy4letTe8OeNH5/+IpXg== X-Google-Smtp-Source: AGHT+IGeeI56h/sev1LuUuQX42ZZFRn2zwkBnX1+PaPri6U3dBBz6r4jAnu/fpiH2SeyIRClL3Q6/I20StkdogT6U+0= X-Received: by 2002:a05:6902:10c3:b0:e38:c366:52b6 with SMTP id 3f1490d57ef6-e38c3666028mr1691523276.23.1732044648351; Tue, 19 Nov 2024 11:30:48 -0800 (PST) MIME-Version: 1.0 References: <20241116175922.3265872-1-pasha.tatashin@soleen.com> <2024111938-anointer-kooky-d4f9@gregkh> In-Reply-To: From: Pasha Tatashin Date: Tue, 19 Nov 2024 14:30:10 -0500 Message-ID: Subject: Re: [RFCv1 0/6] Page Detective To: Roman Gushchin Cc: Greg KH , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org, akpm@linux-foundation.org, corbet@lwn.net, derek.kiernan@amd.com, dragan.cvetic@amd.com, arnd@arndb.de, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, tj@kernel.org, hannes@cmpxchg.org, mhocko@kernel.org, shakeel.butt@linux.dev, muchun.song@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, shuah@kernel.org, vegard.nossum@oracle.com, vattunuru@marvell.com, schalla@marvell.com, david@redhat.com, willy@infradead.org, osalvador@suse.de, usama.anjum@collabora.com, andrii@kernel.org, ryan.roberts@arm.com, peterx@redhat.com, oleg@redhat.com, tandersen@netflix.com, rientjes@google.com, gthelen@google.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 2C0FB1C0005 X-Stat-Signature: 3b8yyk6desqtz3wfmkf3pd5jbwdxnwzu X-HE-Tag: 1732044585-38154 X-HE-Meta: U2FsdGVkX1+waY84QMQjY04vn5nlT35/CQVyVOJp9OaNw/aB6iBPaKzToEqREL3cpN7m3yf4XHqnUvTKg5x3eLjI8ESwe75yZHZXsBk5lz/WhjmQTAPbo+IRjPA+8a5KX6zesn70mQAZpsNVIYDUrjQVLJmpeBwQcuESBaqzffT1xpZLQzJftX1izWQH9NQ9vEMYZgojqF2kbUaGA1eXf2V+aQTERwsP7Cd+DXYL52wWa3+24jse2UpcQadupEJML/pmCBDe3qnqg9Mn3Rx+T6wcLUa5DZdeRXVhCaqBaMqDfbBf5WOO131PHfsZSzbAUpgVyxS5CxUWF7+r4BwP5HyFLDFg8evRQllbYwD4bE63u8Ubmd0tZq62GSle2FlE62P37Tp1AICIG40cNtcrSQs901Avshspu30WNyhnAUrzFhEjtcNF9Pu/lXnuMWpWeF5InqgVe1pPmaMMw3h4Dnkf/EodzoN6oDKP2cgzU17eNW9k86pUI5c1xPiaNDiWkw0zYbg7pOToiyh1Mq4PDCnW6wnYMteoShWRXYtpGACNqWdEzVQho3Syy49eg6EclGtjTxFa1q1rhu1/S87Qt0L0wwEsqa9JSZUFBms2QfBlsFwWg0mVvIbGutbIMDSvBb4Cn9wuTk9CvBKwqDAAJpA/cdhpWHuFinBg15GmVYnSsulCU4zxCSbR76zmd/ct+lULwLTYQtikxfOiLcSQBk93SLCKM2z+IK3YJA8XENdiyCul/iFUFMAKY4IaicfHLaJ2bij6mvsnpNdOHSLX2NHtkdHAlUEN8EJWd+bjEZwNkegd7S03Y2oBNOwgffkl6TxOjOz31fZv0i363MARSeVYQ7yyyzZ6gWrm+JIVKMESXPE3UeMUnUaRxflvjhmS2CbgZM4SKcfAsSAGlmNcmQHuzIZD4ocmwRPT7R1zW5vCKV58qNdQc7goEoISFDfbKLeDuktaUYgizBPAYx2 IWMjYVUh Ew3fs8oKWkNL2gSzTx8RAS3DZtypDWDjW756OTgI67IbzrXJVsMxPV65nQhZXsLKh/q9kwjkg7GPG2eMoev43jUwFAo5eTsJZHRddL/+y3GQNd+JkJTC4bNrd8onPg3IYvLfPF0EnKx7Orj80gtRoKQtS+hV1hEikqhydg39LtxA2uQmpBFg0f4eq/POMOKOQNcn3kTsPSBmnyNiM/QtQOog0+Uth+XNycdFbp5h9aq8oJ7q/GgcJVIyt8EE1tydxs5o/ZP8kawhirssYkMKygkHTq54svLWurqFB4/gV6eLSdhQZi31ccJEggw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 Tue, Nov 19, 2024 at 1:23=E2=80=AFPM Roman Gushchin wrote: > > On Tue, Nov 19, 2024 at 10:08:36AM -0500, Pasha Tatashin wrote: > > On Mon, Nov 18, 2024 at 8:09=E2=80=AFPM Greg KH wrote: > > > > > > On Mon, Nov 18, 2024 at 05:08:42PM -0500, Pasha Tatashin wrote: > > > > Additionally, using crash/drgn is not feasible for us at this time,= it > > > > requires keeping external tools on our hosts, also it requires > > > > approval and a security review for each script before deployment in > > > > our fleet. > > > > > > So it's ok to add a totally insecure kernel feature to your fleet > > > instead? You might want to reconsider that policy decision :) > > > > Hi Greg, > > > > While some risk is inherent, we believe the potential for abuse here > > is limited, especially given the existing CAP_SYS_ADMIN requirement. > > But, even with root access compromised, this tool presents a smaller > > attack surface than alternatives like crash/drgn. It exposes less > > sensitive information, unlike crash/drgn, which could potentially > > allow reading all of kernel memory. > > The problem here is with using dmesg for output. No security-sensitive > information should go there. Even exposing raw kernel pointers is not > considered safe. I am OK in writing the output to a debugfs file in the next version, the only concern I have is that implies that dump_page() would need to be basically duplicated, as it now outputs everything via printk's.