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 67FEFC2BD09 for ; Wed, 3 Jul 2024 14:11:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 00F486B008A; Wed, 3 Jul 2024 10:11:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F008F6B008C; Wed, 3 Jul 2024 10:11:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC8B06B0092; Wed, 3 Jul 2024 10:11:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id BDC666B008A for ; Wed, 3 Jul 2024 10:11:43 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 59AF180C62 for ; Wed, 3 Jul 2024 14:11:43 +0000 (UTC) X-FDA: 82298629686.01.1BA00D2 Received: from mail-ej1-f49.google.com (mail-ej1-f49.google.com [209.85.218.49]) by imf08.hostedemail.com (Postfix) with ESMTP id 566A2160020 for ; Wed, 3 Jul 2024 14:11:41 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=LCUy6YWu; spf=pass (imf08.hostedemail.com: domain of mjguzik@gmail.com designates 209.85.218.49 as permitted sender) smtp.mailfrom=mjguzik@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1720015889; a=rsa-sha256; cv=none; b=z3DTMYBGdX28zTX1pi3lqWse3eoEMuGLnw9V/RXZFsV7GnzgDjToet2HxS7Fm8qajwpFxR lwEtwGkTBtjW09/Tpq4x/OJNzdRD4aHCUqNRnXwyqZ/gYe1MwY/M8sFW0mDJ2nkjFU1fCc M659NrNnuE5vPK4E6axYY4A3dSP7c4Y= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=LCUy6YWu; spf=pass (imf08.hostedemail.com: domain of mjguzik@gmail.com designates 209.85.218.49 as permitted sender) smtp.mailfrom=mjguzik@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1720015889; 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=o+jfOfJ3/jY+788L7avbBrQiHekIeiMO253ikR1T3ag=; b=jGdSsSU1BiFazILWMFrpMyS2GOQd2NJoRRIXzsXNjwny0zM7BwrXuJo0i+EYMfkfSILijH XzjP1y7nSLKrlLLSqaCTrDLqnuvTVkOFdSuzSMJJKmqxcyIqUcIHI6TAPrIZFqi/+7qsFP +2qGgAB7d3crAU2XcEajNIkK/BtkuhM= Received: by mail-ej1-f49.google.com with SMTP id a640c23a62f3a-a7241b2fe79so603921166b.1 for ; Wed, 03 Jul 2024 07:11:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1720015900; x=1720620700; 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=o+jfOfJ3/jY+788L7avbBrQiHekIeiMO253ikR1T3ag=; b=LCUy6YWukLeKbUWI9+NgQfeqcXtOuzecToG3DCY1PtI6XNdIpAPru7TQeQJjmyRgd7 bgczoXWWX+B3fxcyuKBd5UYBUqrlRODhG7NTht/+YfqCFhhcmmC+Uc/jUssreU1lX57P UhEDQnbDxr/TiFjOpJuw8zKIARU72qfGsrDZk+FsKSuDOP3HFGokqLEzCT4vfrNFHsqr iE4D+ZDbF78VxH+hVJXVo2P9tyEvY7iELQ0TJV+bsPHrOW7K50BMjnHeznVYDTMUqezY 6YSesmLn+1/bhzOZIFhPFZZ4tm+6khHCC/qojYe6J6xqd1fFrqgHIcPnRdAogQ1xksMt TBfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720015900; x=1720620700; 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=o+jfOfJ3/jY+788L7avbBrQiHekIeiMO253ikR1T3ag=; b=hIjnzBEf9wGR0R5U9XKJTyoaQl9247RBmC7l9WYtRYk5JxyhfFzJMh5bjVp7Ax9rIY gNz/AncrO+0T7PJM7t3HZwVUdvhy1zYOLHd8wqUcf+NI3Hejs+E9KGhm3g7IqqGrVFlz hRWQ/i4RUqtqTy+hbI2RDASBxAtGq442n5aaf2cbUdC09/Q0sEm5EaQBNgwJNFQt0mni FqQZ8N7nv7VCwtpw+VL/J95cfOLshei6/0dn/oOL4ZhUZE+lxJQBIr7KDfAsKAYVHBlT KTgXjmnjfSMPNU7tOsjnz8FBzige3FZAg9KZxt5W/bVY63yeiZ/XsTUEzq7EVd7SVJox o2yw== X-Forwarded-Encrypted: i=1; AJvYcCUEe+zQ902FXNnLC5ZJgWLNmZAfMf1xFlSCKUQDXw4EKoLcJfNC+ItSZoeq52iQwz5k0/nA9oYOtqY/OE38nBU/G6U= X-Gm-Message-State: AOJu0YxV//VTGvzrSjJbhmAwRt+vTrJJ9QB/5hC5aIRJ36P7uDEYqBOo +W37k/TmBMv5066OAgpmHtIyyVjSBd1Zp3rMMTiZeTPxjBHcbEX+ckOSxonkOI2TRepfXf7l0Yd dCwQ8UDdM/y80tphNGLWpEW5Y1UA= X-Google-Smtp-Source: AGHT+IE3jD545xz4CdEoFN2qZKeLPkj9TIBo3lb9j/pQ0Q6mPtJJR+TY7Q/5JydaEL8odgHFIZ7STtFK6v5V18RVLNg= X-Received: by 2002:a17:906:594:b0:a72:40b4:c845 with SMTP id a640c23a62f3a-a75144badc1mr687998366b.51.1720015899409; Wed, 03 Jul 2024 07:11:39 -0700 (PDT) MIME-Version: 1.0 References: <3g3arsrwnyvv562v2rsfv2ms4ht4mk45vwdkvssxkrjhfjtpdz@umyx5tl2du7o> <6knlkefvujkry65gx6636u6e7rivqrn5kqjovs4ctjg7xtzrmo@2zd4wjx6zcym> <20240703-haftstrafe-anbringen-88ed445e77a4@brauner> In-Reply-To: <20240703-haftstrafe-anbringen-88ed445e77a4@brauner> From: Mateusz Guzik Date: Wed, 3 Jul 2024 16:11:25 +0200 Message-ID: Subject: Re: [linux-next:master] [lockref] d042dae6ad: unixbench.throughput -33.7% regression To: Christian Brauner Cc: Linus Torvalds , kernel test robot , oe-lkp@lists.linux.dev, lkp@intel.com, Linux Memory Management List , linux-kernel@vger.kernel.org, ying.huang@intel.com, feng.tang@intel.com, fengwei.yin@intel.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: frmzisgn9ndzdr5h4gbf1ikeftbregfa X-Rspamd-Queue-Id: 566A2160020 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1720015901-752482 X-HE-Meta: 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 rY0oL+GR K9XXElysMifMYuS29XJVptabdxwbXep901XNMjbo5Prr90KaTxao2QrFb6qkOztlwtBDamtCvjQGIvwCPDWGLZylxdKdgAgAf0IOEbVDSVn8H0S4PlkFwcJWnFXz2oIaFQ4pYcRVLmx8iDwbajGQFtzDUz/tZQSucZ/yNYJ5Fvy+XCQlkLCgROg7GbukJBIw+kArC+WL/hE+Fuf1T+1tFoCQB6Bl8p7ZBPVOIQi+dz1ziurYjaXu4qu+CgBnXoBrN6mWixA4j3Wwz5pyMVO2m5keCWPUdAhMLFvE7qB5jetedk7A1eWU3SKl8ofr2UL9AhSbF4WlgRcOXj0JnPLEGJ+vna91xCEPoLgtfx8mKouBeh2I6tBlu5ASYV+467uYVDDT6 X-Bogosity: Ham, tests=bogofilter, spamicity=0.003840, 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 Wed, Jul 3, 2024 at 4:09=E2=80=AFPM Christian Brauner wrote: > > > As a side note this is where I should also note the *current* LSM hooks > > are racy as is. Suppose you can stat a particular file now, but a chow= n > > to 1234 means you can't. Then your stat call can race against chown + > > other ops. You can end up in a state where LSMs gave a green light and > > only then the state changed to one you are not allowed to look at. This > > Fwiw, we've discussed this before. And my opinion is that we should > absolute not care about this. I have no interest in complicating path > lookup or any codepath to make these hooks less racy. This raciness they > have to deal with. This is not a comment on your patch but just that the > raciness of security hooks is not a problem we should care to solve > imho. If we go down that road we'll all slowly go insane trying to give > state change guarantees to layers that hook into the VFS in really odd > locations. Well I noted I have no interest in working on it anyway, so... I think we are good here on this front :) --=20 Mateusz Guzik