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 0596DC7EE23 for ; Tue, 23 May 2023 07:46:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 696E2900003; Tue, 23 May 2023 03:46:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 646226B0078; Tue, 23 May 2023 03:46:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53476900003; Tue, 23 May 2023 03:46:07 -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 38AE36B0075 for ; Tue, 23 May 2023 03:46:07 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 0A11AAE110 for ; Tue, 23 May 2023 07:46:07 +0000 (UTC) X-FDA: 80820736374.11.BC21A54 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf26.hostedemail.com (Postfix) with ESMTP id 12E50140015 for ; Tue, 23 May 2023 07:46:03 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=fdDAJd9C; spf=pass (imf26.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1684827964; 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=HE8Z1r+4tl2uPWUmoH+B2Mu5/vsobbHlaWuGe2SIGH0=; b=MTOf+K8uheXL+37orvjFQEzE4fys5dRg+04LXdviQFs7LDstaSL1zPWGFaX6h5ITE1T9TW IdQNAeJvxP+VdrRTbN1bk1JK5cvGiOhJAyY+Xftd4NmzFvWVWwm3+na68ordcck4QliOH6 Y4Db+63acI/JEH0T63l172NPQ2FnN7c= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1684827964; a=rsa-sha256; cv=none; b=vEWpbo6POowyysmcIrZsgjvdUyisFgYJBI9GbprTOUxsmT+UEdbTRXhus2bNC+giRORr4x nYi52tT22Moo2g9uJEKy8WSIWdHUoOS4SVEObFR8nyXSZPRj2plqguWXUY8iZe1cw3zOZK d3a4CnP7HPDGjTbSf6vz+nOAobl2eoE= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=fdDAJd9C; spf=pass (imf26.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 3D5F820400; Tue, 23 May 2023 07:46:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1684827962; h=from:from:reply-to: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; bh=HE8Z1r+4tl2uPWUmoH+B2Mu5/vsobbHlaWuGe2SIGH0=; b=fdDAJd9CyqjSrnt3PsKFrRrefe+mjo30LoRyztAS20x9AjqcNg0GWxXukwc7b7Mec4DBU4 H2vA0ca3ogceMD5R470OfC6cnigF7Zs4pCd0kXnpxTxrWqW/elZntnFtZf6bKqamEiGKab 59gKyP6W/faL+zy8JQV+buAk5mtGmmY= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0386B13588; Tue, 23 May 2023 07:46:01 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id lSB7OTlvbGSPJwAAMHmgww (envelope-from ); Tue, 23 May 2023 07:46:01 +0000 Date: Tue, 23 May 2023 09:46:01 +0200 From: Michal Hocko To: Linus Torvalds Cc: David Rientjes , David Hildenbrand , Andrew Morton , Alex Shi , Johannes Weiner , Matthew Wilcox , Alexander Duyck , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch] mm, debug: allow suppressing panic on CONFIG_DEBUG_VM checks Message-ID: References: <53dd9df8-e88f-f466-89f9-3fa141a10267@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: 12E50140015 X-Rspam-User: X-Stat-Signature: rh98ojpnf5y6aou7kfinfwchkwsnqp88 X-Rspamd-Server: rspam03 X-HE-Tag: 1684827963-398945 X-HE-Meta: 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 QDTU1iWm zjMmdSw5eLEHPlld0pzSVexwnHL00woPSWPQ+SugfY3uwhY+6u9nX94Hga6Lfj9LiM/2f32HYjtqeLFwfD/HD9WWjLLAIXjCVqowQXNMFIqHF7yCHyOTlF9dkUq29coVskxyXNvbchO8CueL5EC++ZsM50f0uBwl3JTDWfbvGm0FvV/1Ir1UJOJYcRBETM9iyEslnj1uAiT/wgqOGZ2apYJRgsFXYANMDldUb 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: On Mon 22-05-23 11:48:52, Linus Torvalds wrote: > On Mon, May 22, 2023 at 11:39 AM David Rientjes wrote: > > > > I think VM_BUG_ON*() and friends are used to crash the kernel for > > debugging so that we get a crash dump and because some variants don't > > exist for VM_WARN_ON(). > > I do think that from a VM developer standpoint, I think it should be > fine to just effectively turn VM_BUG_ON() into WARN_ON_ONCE() together > with panic_on_warn. This is a very good idea. VM_BUG_ON has always been rather special and from my past experience people are not really sure when to use it. It is a conditional thing so it cannot be really used for really BUG_ON cases. Turning them into VM_WARN (not sure about ONCE) makes a lot of sense because as you say you can make them panic easily. -- Michal Hocko SUSE Labs