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 C228DC433F5 for ; Fri, 20 May 2022 16:42:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 381F86B0071; Fri, 20 May 2022 12:42:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3300F6B0072; Fri, 20 May 2022 12:42:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F74A6B0073; Fri, 20 May 2022 12:42:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 113E16B0071 for ; Fri, 20 May 2022 12:42:59 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id E42A521A29 for ; Fri, 20 May 2022 16:42:58 +0000 (UTC) X-FDA: 79486690836.02.7E7BEBD Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf28.hostedemail.com (Postfix) with ESMTP id 3319BC0029 for ; Fri, 20 May 2022 16:42:30 +0000 (UTC) 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-out1.suse.de (Postfix) with ESMTPS id E7EF421B0B; Fri, 20 May 2022 16:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1653064976; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=bLqQdn9HN5Q/zAvC6Hk4QDRgTKfhEBhanRUuT3mU5pA=; b=igafjCptMEV96uVLVKjnxoDCXAr0C7f6sVRpvSX9tPGhJtTxOzhDBhfXPXiJghYdyexRt/ OVlnUM9mGYOKK9TBJTurx2f23M+UlCnDwq8bHhBVF8OM5fZFq/wu4xGs+UdA/wzpyJ5nmA an/giytymusbucxLuECJ0nQzxTlpzEc= 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 C5C9E13AF4; Fri, 20 May 2022 16:42:56 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id jZFXLxDFh2JAMwAAMHmgww (envelope-from ); Fri, 20 May 2022 16:42:56 +0000 Date: Fri, 20 May 2022 18:42:55 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Tadeusz Struk Cc: Tejun Heo , Hillf Danton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzbot+e42ae441c3b10acf9e9d@syzkaller.appspotmail.com Subject: Re: [PATCH] cgroup: don't queue css_release_work if one already pending Message-ID: <20220520164255.GB17335@blackbody.suse.cz> References: <20220412192459.227740-1-tadeusz.struk@linaro.org> <20220414164409.GA5404@blackbody.suse.cz> <20220422100400.GA29552@blackbody.suse.cz> <20220519112319.2455-1-hdanton@sina.com> <25fb057a-077f-b601-dcb7-130071c733db@linaro.org> <489592f6-b783-7bdb-2cc8-0c8e35ebc674@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <489592f6-b783-7bdb-2cc8-0c8e35ebc674@linaro.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3319BC0029 X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=igafjCpt; spf=pass (imf28.hostedemail.com: domain of mkoutny@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mkoutny@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-Stat-Signature: 5usuzrgz7xfrpupoickm4ktr3jr9aaky X-HE-Tag: 1653064950-385965 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 Fri, May 20, 2022 at 09:38:12AM -0700, Tadeusz Struk wrote: > as this is a result of enqueuing the same css->destroy_work onto the same WQ, > one on the rcu path and one on the css_release path. > I will prototype it today and test with syzbot. In my understanding, you'd need two independent work_structs in a css, not two separate workqueues to put the single entry on. Michal