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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 063A5C10F14 for ; Fri, 12 Apr 2019 16:50:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9752320850 for ; Fri, 12 Apr 2019 16:50:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9752320850 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ECB566B000C; Fri, 12 Apr 2019 12:50:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E79C26B000D; Fri, 12 Apr 2019 12:50:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D90066B0010; Fri, 12 Apr 2019 12:50:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by kanga.kvack.org (Postfix) with ESMTP id B74386B000C for ; Fri, 12 Apr 2019 12:50:35 -0400 (EDT) Received: by mail-qt1-f199.google.com with SMTP id x58so9340330qtc.1 for ; Fri, 12 Apr 2019 09:50:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:organization :from:in-reply-to:references:to:cc:subject:mime-version:content-id :date:message-id; bh=oNaOnJP5Pkva+H57ZtsndfrIrh/zoUcpLiQPmhV5R9g=; b=NU2pQfool/vT7eqhRzhKjXquzWj0qjFmo0Q66p2dqmEc3Is6r1xPATVfJ0ds3p1ygo L6wo9Ouajlk0+kSVJxB2HO6ptT0v+45p2rdw5ntMUZ7UvVkQk/vnjAZwgxRFWqiV73b9 oW3QmLuRaYrGDwtjOx0261rlXDwYXERXY6TaDzyR7OElj0ICC2iZW/Ttp3rOII6FPWDv Tkbv2JIbDU6pXXAdZ1BmPGnavF5OMQI2Rvv+HI8J+Us4Zk/vRnfjxkDOHKFpDBcCHoXL LFOn8u3M86YLBR9m03XPNSOZWsDkf1FFKIVTdY9nRFrGYHjeVHWgOHcJCdKw9SFcVykj a5zw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of dhowells@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=dhowells@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: APjAAAUg2jET0cSVX7E+5CRtnvha/LaO1W2rCEdMbix/6LiokXSmHIBR nkbTVBS+aoJZIhFeSFbdg5CRnicwSTtxao+14efWp1RWe+G+kPybJKA/3YF0F4DS/VHQDfLboLF wR+j3ZMVGmLmLer7k5hDhr2m/qC/QE/Upuqv6gNmYxYmcqTk6T0X/bskbVWlIm7xF1g== X-Received: by 2002:ac8:247c:: with SMTP id d57mr2821407qtd.308.1555087835507; Fri, 12 Apr 2019 09:50:35 -0700 (PDT) X-Google-Smtp-Source: APXvYqzeiV+IM4JivgyE1LocZSTkvaUun4Amjf2jDruxxxmHDxIiD3uiKGpwOjIkW/IZHX6V/Uya X-Received: by 2002:ac8:247c:: with SMTP id d57mr2821355qtd.308.1555087834666; Fri, 12 Apr 2019 09:50:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555087834; cv=none; d=google.com; s=arc-20160816; b=meJbA7ZL8JOFd/OfA9YzhxY36VqsTiujJfstST7XCvBzbPCrK1fYTHgOxNA5x1Oeks VXP5xEdQ2cPU4IYypQ+H1FH2R3gfnrjYwXtQLUjyFUuMi5gkZstNDpHpRDzXwASQbU5X +xcUpU1uGJohJvXVDlD6C4vb1ACNsMtKR3picWzKMmk1eeRIZcK+GdUXtuAO32ZPqsVW gtd+QmqYQ8Q9UFWH4h8oRDtsNFE1knfl4mTIBmhCDrHk0XQ5Hi1vQXHH7CrfSGu1RyH8 bz5/TEtSW9AssqydH7xYBo41cz9bBupxUwFR25aZtIvCj+phGE3wBFOEoLy/af/w5TdJ eiyQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:content-id:mime-version:subject:cc:to:references :in-reply-to:from:organization; bh=oNaOnJP5Pkva+H57ZtsndfrIrh/zoUcpLiQPmhV5R9g=; b=jf+Gu6yGtOGGLxGwnSsD6LZcc1uA8mit6L8YRfwAThvLxrmQoezsgDBLTbaOVB0Xla JfmirWnmXlC6/8a4G9zCNqgH6Fh2aqKdxGNZawC+HN9KVgxWCPOp1bP5gkH56FGHLi9R CYhxbvOMOD3Xk5Y+CMqXtT0SWXRMK9z+VI1VVORlX4qw1b8Y+HojPC54v724BJc9PmXs B9Vv6oov8lD0WxhEUYGGV2dO1Cy+RhYXn4+mBgqPt7K3HetHigV3vM+MJQz9up5nUUY+ psx2VKt2cqC3w/Q+i4Yy6RL6rQcYUEliCg9AH6JSqwRV10LLbEij8tnMsqlpfH8jw0KQ qSIA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dhowells@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=dhowells@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id f25si2549496qta.270.2019.04.12.09.50.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 Apr 2019 09:50:34 -0700 (PDT) Received-SPF: pass (google.com: domain of dhowells@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dhowells@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=dhowells@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9822D330255; Fri, 12 Apr 2019 16:50:33 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-98.rdu2.redhat.com [10.10.121.98]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4875E60BEC; Fri, 12 Apr 2019 16:50:31 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <5cae03c4.iIPk2cWlfmzP0Zgy%lkp@intel.com> <20190411193906.GA12232@hirez.programming.kicks-ass.net> <20190411195424.GL14281@hirez.programming.kicks-ass.net> <20190411211348.GA8451@worktop.programming.kicks-ass.net> <20190412105633.GM14281@hirez.programming.kicks-ass.net> To: Linus Torvalds Cc: dhowells@redhat.com, Peter Zijlstra , kernel test robot , LKP , Linux List Kernel Mailing , Linux-MM , linux-arch , Ingo Molnar , Thomas Gleixner , Will Deacon , Andy Lutomirski , Nadav Amit Subject: Re: 1808d65b55 ("asm-generic/tlb: Remove arch_tlb*_mmu()"): BUG: KASAN: stack-out-of-bounds in __change_page_attr_set_clr MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <5889.1555087830.1@warthog.procyon.org.uk> Date: Fri, 12 Apr 2019 17:50:30 +0100 Message-ID: <5890.1555087830@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 12 Apr 2019 16:50:33 +0000 (UTC) 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: Linus Torvalds wrote: > We should never have stack alignment bigger than 16 bytes. And > preferably not even that. At least one arch I know of (FRV) had instructions that could atomically load/store register pairs or register quads, but they had to be pair- or quad-aligned (ie. 8- or 16-byte), which made for more efficient code if you could use them. I don't know whether any arch we currently support has features like this (I know some have multi-reg load/stores, but they seem to require only word-alignment). David