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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15C21C54FDF for ; Thu, 30 Jul 2026 09:07:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1285F6B00AB; Thu, 30 Jul 2026 05:07:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FF786B00AC; Thu, 30 Jul 2026 05:07:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F30A86B00AD; Thu, 30 Jul 2026 05:07:52 -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 CBF716B00AB for ; Thu, 30 Jul 2026 05:07:52 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 5539E1A095C for ; Thu, 30 Jul 2026 09:07:52 +0000 (UTC) X-FDA: 85044865584.21.3AA2970 Received: from mail-lf1-f42.google.com (mail-lf1-f42.google.com [209.85.167.42]) by imf28.hostedemail.com (Postfix) with ESMTP id 979CEC0003 for ; Thu, 30 Jul 2026 09:07:50 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=IBSzQR5v; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of iprintercanon@gmail.com designates 209.85.167.42 as permitted sender) smtp.mailfrom=iprintercanon@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785402470; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=jHwhbqYZcyFMLFasS7DHToFvnOjYKNx0LAh55A/C47Q=; b=z5wA7mOoogl9XDSRBHBFbshIf8KJvU237tvPQBt9zF9s/10dQsHMAIyXLdfCo0Q2+NGZGp NdGqkfYDTrAkKBtK0f92jF1zblcBdkc3aClaC0ZMkWn3In0ccure6XaPBWzsibWGh0TKKN 6C0qJ3j1Cm9onyPNaMN5DwVYJDmt9Fc= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=IBSzQR5v; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of iprintercanon@gmail.com designates 209.85.167.42 as permitted sender) smtp.mailfrom=iprintercanon@gmail.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785402470; b=gVtV0nyCTTj9VruY7WH/vBwPw8sCKm4OyAVzbWykm/uVIsz4l9QHoFaIMtdwASgKEb9Kup 4rWtCne0+ad65aOA1udbILB0qTpBEFAl69sWfAt9cwCfVkjF5IIn/Ln3tf7+WcJ7js2o/B qdoDH0XDr+GJkZg39Iv+M6I/WU2czHY= Received: by mail-lf1-f42.google.com with SMTP id 2adb3069b0e04-5b021916bd3so1811787e87.3 for ; Thu, 30 Jul 2026 02:07:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785402469; x=1786007269; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=jHwhbqYZcyFMLFasS7DHToFvnOjYKNx0LAh55A/C47Q=; b=IBSzQR5vzb44L1r17etIWeWh9M+SGN/4ic/urc+pg4ddfpSO62Ly9ovkfdyUi8m7d2 tK3C1coQs/bbICETSLZa3HH6lHSWe+D71Dgn/BCIbNqpwBI7F8N3LWQ349VRJ1mRlh2/ hSJQgu4o9B8cHJpKb3CgggHP1ywsMVu3rhIV0JyLgXfXqu3UEBX2w0qeWS+HcvVwHanU OdD1nUD3toBJiDe9Sav0FhT1D2cafMlaYX9jtVNnH6Y2DzmH0WCgX4G2or/IWlP2oXPw gzRulP9wrgfizld9PDl/L4d+PO+dk9yt4hOBk3lbZhiMrAJ9Wh5wRS63KcvPGCRbdNXz k2Iw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785402469; x=1786007269; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=jHwhbqYZcyFMLFasS7DHToFvnOjYKNx0LAh55A/C47Q=; b=ITGSNCDGvwk/eyHZEB5YrhWnIJ6GiLIIj5YkZIpAt+CVpXeWH71G8vc8gjcUcdR3sX J3oNVzm7utueLRgcVWOcq1eUd1SMTVYCH/RLaZcIF3yP97J1+D1/KH9Ic9q5jbWFJGOA Dn94iWan4PoEDtGT4b4tEGiEh5tsD8KxhMgTzikQafiFkLY245zFq3Q5Dye85zGbA3po I5RNnCvu1Hi0aaQ2AwVO0+wbYQ9e7yuG1NRFaGCPQNrSlPHXPK2Jxzhe7bUJOIv0azA+ TqltZOhC12Czzro0Oh4fqBdUH+xxYV9z91JYAB0U1DzlrpgBlQZKm5pIUJKvlPwa7k+c SCEQ== X-Gm-Message-State: AOJu0YwpEUZqmxnJL6sduYvVE5mN8S8GcxolQddpXu1/f3u+frpjgB6+ leaFo8jdhm8DKCAeFP2kG8RNMWKKm585/6TeMgX4lpLBmaFF1Kh+8bWq X-Gm-Gg: AR+sD10AdDMlKUZSjTQ3KQHs3QAhbsStGV5YKiScUJsAXSLc5t0QCLtbrpsKPf+2ucT Mlk3a9tZT2oLHhrzg2Jqd5I/DeEivuWsl7X9tS/I69wmbfNzdirmq9T0QPHUAK4bkjThan6vezS EtOsz19MoucsI2UW22/qRI2mWYEvv6G1bLaqbsxtU8YSjPp/7oc/O6B/yftfjZPqurUhPfDAdVh 5vXCQBahS08KJ6BwnJyKW8KqclmK3vrFq+f1X6xp0XRosQTbjZ28d3TqPBre/+gvxfSn/VX3avr ckOdcsn6T9lSon3X66LnEO5seiTCdv1DBKV+5vh2eZBXfLUFn0oW6BWNmqH2wfDZFT0eZ5MIgUN CvnRDVDIOK2lqWJr4HXFT1xxAF28asMP1IL+SE8Rq1BAGThG5XnnfIFUO0Xcfrq64y3js/qfIvF V+VDu7B1aE3lwIoz3MZ7C9DBiK4+2roLxnMLtKLMqXcfAXwIYUAUjpfGjfWCGHBC9gw7+231rP/ VVdZ6G2zLAFWj0wRieI5EZINdHo2M/omJ48DdDz8UnsNuHUteieTIZytrepspsEeERH X-Received: by 2002:a05:6512:108d:b0:5aa:8822:c946 with SMTP id 2adb3069b0e04-5b2db37ec16mr338558e87.48.1785402468876; Thu, 30 Jul 2026 02:07:48 -0700 (PDT) Received: from localhost.localdomain (46-138-176-102.dynamic.spd-mgts.ru. [46.138.176.102]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b2db942de5sm216643e87.10.2026.07.30.02.07.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jul 2026 02:07:48 -0700 (PDT) From: Artem Lytkin To: Matthew Wilcox Cc: linux-mm@kvack.org, akpm@linux-foundation.org, urezki@gmail.com, shivamkalra98@zohomail.in, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmalloc: make vm_struct.nr_pages an unsigned long Date: Thu, 30 Jul 2026 12:07:27 +0300 Message-ID: <20260730090727.65911-1-iprintercanon@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: <20260729175708.7074-1-iprintercanon@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 979CEC0003 X-Rspam-User: X-Stat-Signature: 74rjuriscyxn9fx34c5tgxyigxp77oux X-HE-Tag: 1785402470-913311 X-HE-Meta: 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 4z+ynxgr 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 29, 2026 at 07:28:36PM +0100, Matthew Wilcox wrote: > I'm not saying we shouldn't fix this, but it's all theoretical for now, > right? The 2^32 page part is, yes, and my opening sentence pointed at the wrong thing. What went wrong twice wasn't a page count, it was a byte count. nr_pages is unsigned int, so nr_pages << PAGE_SHIFT is 32-bit arithmetic and wraps at 4GiB of bytes, which is 2^20 pages. In vread_iter() that made /proc/kcore hand back zeros for a 4GiB area as a successful read, and any machine with more than 4GiB of memory can allocate one. So the reachable part is 4GiB and the 16TiB framing was me leading with the wrong number. To answer the other half of it, and Andrew's question too: no report behind any of this, I found it reading the code. v2 says so in as many words. Artem