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 36BEBEB64DC for ; Tue, 11 Jul 2023 15:35:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A1C246B0072; Tue, 11 Jul 2023 11:35:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9CC936B0075; Tue, 11 Jul 2023 11:35:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 86C316B0078; Tue, 11 Jul 2023 11:35:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 749696B0072 for ; Tue, 11 Jul 2023 11:35:13 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 3C88F402D9 for ; Tue, 11 Jul 2023 15:35:13 +0000 (UTC) X-FDA: 80999729706.08.0624903 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf13.hostedemail.com (Postfix) with ESMTP id 6206C20002 for ; Tue, 11 Jul 2023 15:35:11 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uUePYcj4; spf=pass (imf13.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1689089711; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=k0j7YIaKnFmVrWcUpImqiP9j2bqvdSmldf/CxJMiCJs=; b=gzS1qYvp6QzCvxoB1xTDpvclz3Z7MW5KOmt81418ELmUADIfhuFlXqJ/gXeLtTlrkQuOy8 6j2RBb+SFVNadxTUoqV19O56NiDaxbQXr8PNRdrYQLZoi2uTAOgBg4qitJAiS03qB0zNQI nl3cBbauK7kreJTU0t72g3C+YRBVGmE= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uUePYcj4; spf=pass (imf13.hostedemail.com: domain of broonie@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=broonie@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1689089711; a=rsa-sha256; cv=none; b=YVg4Zd0fmpeg+YDo0zNKMZbeZHTbD+gp4KXVx7QSognutcWgebq9FW/zJ3B6DO+8mzZFDW Rr041ANpPt1lKvZqKBnF89evKYZYirtzxCE4ZM4tgz0i64RWQ1Sh8LsTRqCk9CSdUaH7QA AW1KljK4K6KadFMCE0AUpo5RXzXCqcg= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 790936155A; Tue, 11 Jul 2023 15:35:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0273DC433C7; Tue, 11 Jul 2023 15:35:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689089710; bh=UXghBE2NE/kW/pRVkn/IvERI1bxXZoJhXe4i/ktt2/8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uUePYcj4YswI66LM2cxNpfR8NTSITOssW6XY7LlceoOoQ4i50geInh/FKf09BG3DL uLQuJKsTB1CzCAYUVRqKYrIcz7xpF7PrJ13E5twXvT70sbVRpu9YVosQhScwUP/kyu PKtVVB+GMHbis5hvWfoLOcmfXV1f26L+iGoXg6QD6FhqlngDy2RmQswqObrPdh4NVI nDkjPElO5QsZUUGQQMWk3Y2Ta+Bh7BWK8xJhlE0CPQHmvqJNcwkf87jXLEgaRTwkUO NUFGnnZjlPtviwjdsYXV7ETO7mJL6TTdw4A3giQgzutpOTTJniIEXpZymcOewKWOkn O+DRmo1O/ECuw== Date: Tue, 11 Jul 2023 16:34:59 +0100 From: Mark Brown To: Hugh Dickins Cc: Lorenzo Stoakes , Andrew Morton , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Huang Ying , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Ryan Roberts , linux-kernel@vger.kernel.org, linux-mm@kvack.org, regressions@leemhuis.info, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 12/32] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel() Message-ID: References: <696386a-84f8-b33c-82e5-f865ed6eb39@google.com> <42279f1f-7b82-40dc-8546-86171018729c@sirena.org.uk> <901ae88d-ad0c-4e9d-b199-f1566cc62a00@lucifer.local> <977ddee4-35f0-fcd1-2fd-1c3057e7ea2a@google.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="w4g5Ya+dx+5ErXu8" Content-Disposition: inline In-Reply-To: <977ddee4-35f0-fcd1-2fd-1c3057e7ea2a@google.com> X-Cookie: marriage, n.: X-Rspamd-Queue-Id: 6206C20002 X-Rspam-User: X-Stat-Signature: jmugtaidmiytfoewc36jjttjtj64iiri X-Rspamd-Server: rspam01 X-HE-Tag: 1689089711-593454 X-HE-Meta: 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 ehf5Msqm NLZVbFIa5t8lKlFtktKMJfOZ5TdBaxdXTjq2xwD4MbynrBOQOLX0/HZfRmRQvX3xlW0WtnZU1L1jG+7Sndl7CZyK8nnhYEfrMNK3wDoQDL6JZz24xRKoWza6gwD76kWGKCp6fzUIo9aYHdI66MPbljvJL/coY1h9BFLeHlBWRH8CmxQutXNdsPnYxAAEIm1JGod7mjTiD8IW6+ZNtH9NCTX8fGFLUuLlCjB442KdRnYlEcmU3+J2WVWMLUIb2jYokQklTCZZ4FICwHPa6VrNoeltD3wZWH8LSOMB1hKy8AeN7UlogZaw0Rf7oaiAZIWODSgOWFF2tzwjmzHR2pc85KNwdA86vr+T7yhOztinPvth9U33A7+x5zZGc8y9uflDPmv+4VIAXWdAnbT8= 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: --w4g5Ya+dx+5ErXu8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jul 10, 2023 at 09:34:42PM -0700, Hugh Dickins wrote: > This feels like one of those bugs which depends on the code size in > some way (a bit like those bugs we used to have, where a function was > mistakenly marked __init, then in some configs its code landed on a > page which got freed at startup - I'm not saying this is that at all, > just saying it feels weird in that way). > Yet your bisection converges convincingly, which I wouldn't expect > in that case. Yes, it smells like code size or something other than the commit itself, I have seen this sort of behaviour before where something nearby in history introduced something which was then triggered by whatever the bisect points at. > I suppose I should ask you to try reverting this 0d1c81edc61e alone > from 6.5-rc1: the consistency of your bisection implies that it will > "fix" the issues, and it is a commit which we could drop. It makes > me a little nervous, applying userspace-pagetable validation to kernel > pagetables, so I don't want to drop it; and it would really be cargo- > culting to drop it without understanding. But we could drop it. I did look at that, it doesn't revert cleanly by itself. Your other suggestions are all good - I'll poke at them. My suspicion is that there's some longer standing breakage elsewhere and your series (or even just this patch) just happens to push into happening reliably, had it not been a mm change and a memory related bug I'd probably have just discounted the bisect result. --w4g5Ya+dx+5ErXu8 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEyBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmStdqMACgkQJNaLcl1U h9B2ygf3WcoveZBcNCDFtF0/hH7JWuCVAeL856Ci/azCtT0y2w6cpUP3VO1xTxDr m8YfCM2mWlg/iKZ6yC1FkJvgr1m2ZjGA+Q2awiZUiZt/htJOgDnQ3KMRt8jGvSs3 ctdg8gdYBz4LK9TOz5LPKX5UsjiDBcebYEWqAkgvy3ZSGdubnQ8WqlEmDXT/dlOL 3xE4fyDXFPMtZThRYoE0wrN5EwVLJTaE7O/8TpLhPxK2iXbQCgASZhSfe23CCKKF k5C2XwR97eTiT/uwJtN2aYy/y+ay7+8Do7JEGu2hMJBm8/X7ZUrLtms8MaKNvTGJ 83r2M8FrNLXbhVdHNQJ249P5rF99 =ztfN -----END PGP SIGNATURE----- --w4g5Ya+dx+5ErXu8--