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 4018CC61CE7 for ; Sat, 7 Jun 2025 14:12:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 85F846B0088; Sat, 7 Jun 2025 10:12:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 811096B0089; Sat, 7 Jun 2025 10:12:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 700B16B008A; Sat, 7 Jun 2025 10:12:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 4EF316B0088 for ; Sat, 7 Jun 2025 10:12:10 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id F3DDE162230 for ; Sat, 7 Jun 2025 14:12:09 +0000 (UTC) X-FDA: 83528793978.24.1A45A93 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) by imf04.hostedemail.com (Postfix) with ESMTP id B034A40010 for ; Sat, 7 Jun 2025 14:12:06 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=RksD7TO5; spf=pass (imf04.hostedemail.com: domain of dave.hansen@intel.com designates 192.198.163.12 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749305527; 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=tOsURfwpu5JIYYGzjKsueBWYxy8LFs6ja4Urw/zMLwY=; b=GRlRkraEoqOe5413uhpPMOAnAfCj5pnvMhlXv/hBPDTznKZIfIhyPDzR583VXUi1h2ql+y dll52iZYC9Xms+A/pD++szJ5HW8foVC7YsAe/znED+AB9ObS4PpLi9khs4fk99L06Xn6Gg umhgY/8jaC9Adf6904waYfOw3ke0K7g= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=RksD7TO5; spf=pass (imf04.hostedemail.com: domain of dave.hansen@intel.com designates 192.198.163.12 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1749305527; a=rsa-sha256; cv=none; b=PupC2bVejxWJ9pUbDNPFhdWdsMxZK8EoxMXP8ypEjzYSSXRitXw4K/oHjMVhvuTEdQ+tey MjZYqji5s7FTzn4c7NgIBb2imQeyAWWb39WZY10ggHo3tgTcsgPbdGKcu4C3c1x2CBq4U+ bpFakhyHHz09O8ZMX54zFGBJV53/9xE= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1749305527; x=1780841527; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=tOsURfwpu5JIYYGzjKsueBWYxy8LFs6ja4Urw/zMLwY=; b=RksD7TO5gSpjMHVH86Sw48oiAe+Pdy+6ym2GhpRk15np9ynrBniBSmVM YSGrcw2zNWOs7zPxqWwegEdmPSnWhj1LT0NVwQMI/vdBmSIuTQF5pPVnA xB+L47TO8p6NkwEOL+bpGYyc8HHKTtOBUZJUAtFDo5xD5V3w2Rr72vZbK UKx2TaCFCsLtr/kP7QYFaa/lc0zIlIAfWXsvln8R1EbL3Mj2INn0ffiVn qSGcltiQIFnQgZ2uwSLt4IPdXZXRX81wR0KB5aHGHPEgTExc9E5jwvT5B rIEGeJs8dl0sdzKXu8LtilAAdj24v1pqhIgl2wBn+V1FpKZ1UKz0oGzuf g==; X-CSE-ConnectionGUID: G79KwwAkS8eCqWAkm9jyzQ== X-CSE-MsgGUID: yot8TPkcQLWuhd6M9vJPMw== X-IronPort-AV: E=McAfee;i="6800,10657,11457"; a="55231456" X-IronPort-AV: E=Sophos;i="6.16,218,1744095600"; d="scan'208";a="55231456" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2025 07:12:05 -0700 X-CSE-ConnectionGUID: tBMhaICIR3CN1VGkDijZZw== X-CSE-MsgGUID: QIrKOpfMQBC9VEoVh73s9Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,218,1744095600"; d="scan'208";a="169264059" Received: from msatwood-mobl.amr.corp.intel.com (HELO [10.125.111.75]) ([10.125.111.75]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2025 07:12:03 -0700 Message-ID: <34a2bfa5-30e1-4ba0-ac36-bf07a0d60d97@intel.com> Date: Sat, 7 Jun 2025 07:12:02 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Large modules with 6.15 [was: [PATCH v4 6/6] percpu/x86: Enable strict percpu checks via named AS qualifiers] To: Uros Bizjak Cc: Jiri Slaby , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-bcachefs@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, Nadav Amit , Dennis Zhou , Tejun Heo , Christoph Lameter , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Linus Torvalds , Andy Lutomirski , Brian Gerst , Peter Zijlstra , Shung-Hsi Yu , Alexei Starovoitov References: <20250127160709.80604-1-ubizjak@gmail.com> <20250127160709.80604-7-ubizjak@gmail.com> <02c00acd-9518-4371-be2c-eb63e5d11d9c@kernel.org> <9767d411-81dc-491b-b6da-419240065ffe@kernel.org> <6412d84a-edc3-4723-89f1-b2017fb0d1ea@intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: B034A40010 X-Rspamd-Server: rspam09 X-Stat-Signature: jupz4e4p5k839cgwfnerrf3z9w7w36zt X-HE-Tag: 1749305526-711473 X-HE-Meta: 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 MTI5miQm RF8hd9cXKdOZqnvbw8Siz/kzOtySL7bEwKZ80PrMNPouqXP8wdWwsONP0vEhcCbF659YflK1TasCSZXZXGD+V2HNLODv9lFyDQ4DtBRD6jQ1XJ06ldllscu/isFdKS2RXAUH7n6Wq2jEOM1vyvnCmKo17vUD4HOkOwSGPyld7OdkGWEUz0WVyKLUhB2DXR4kFm+gRYjLo1NuO6u1YAc0Ocawjbt4kub6y61ww9KB4ftaPgtruAA/WTJeLCcdjR6CARUvYsRo2YIdMXwRTcJlg4RrvAw== 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 6/7/25 01:52, Uros Bizjak wrote: > Let me reiterate what the patch brings to the table. It prevents > invalid references of per cpu variables to non-percpu locations. Yes, it's a very useful mechanism. That's exactly why I want to preserve it for developers or things like 0day that do build tests and don't care about modules quadrupling in size. > Hiding these checks behind the CONFIG_EXPERT option breaks the > intention of the patch. IMO, it should be always enabled to avoid > errors, mentioned in the previous paragraph, already during the > development time. I agree, it should always be enabled ... eventually. But now now. That's why we're having this conversation: it's breaking too many things and needs to be disabled. > I'm much more inclined to James' proposal. Maybe we can disable these > checks in v6.15 stable series, but leave them in v6.16? This would > leave a couple of months for distributions to update libbpf. I'd be worried that it will hit a whole bunch of folks doing 6.16 work. I was expecting to revert it _everywhere_ for now, if we go the revert route. James, by partial revert, did you mean to revert in stable but not mainline? I assumed you meant to just revert patch 6/6 of the series (stable and mainline) but leave 1-5 in place so turning it back on later was easier.