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 348D6C433EF for ; Thu, 3 Feb 2022 23:19:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 548B26B0071; Thu, 3 Feb 2022 18:19:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4F7786B0072; Thu, 3 Feb 2022 18:19:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3978B6B0074; Thu, 3 Feb 2022 18:19:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 25E6E6B0071 for ; Thu, 3 Feb 2022 18:19:17 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id D2C2F20C75 for ; Thu, 3 Feb 2022 23:19:16 +0000 (UTC) X-FDA: 79103036754.01.6FF0949 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf07.hostedemail.com (Postfix) with ESMTP id 359AB40002 for ; Thu, 3 Feb 2022 23:19:16 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 79DCEB835F0; Thu, 3 Feb 2022 23:19:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4669C340E8; Thu, 3 Feb 2022 23:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1643930353; bh=QAHuBZ+lX2RUpSHwgEocw6rmoaPtXDKxXRloyq8ZEec=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=CjspKTS1bIPfibcKITrREBKeKQlZmkOykOg6E5BXy0zEwtnZIRsD4PFTz6byuzX9r +lFOI56eEYmixY6vm3Qq137KAT2W9/9MD417k/Q5JaOKMvDs+3P27ZGynHSXbyEx35 c/dnEzqXOQRUU29oM0utwLQvmRN+owV/pen03xtc= Date: Thu, 3 Feb 2022 15:19:12 -0800 From: Andrew Morton To: Roman Gushchin Cc: , , Alexander Egorenkov , Waiman Long , Tejun Heo , Johannes Weiner , Shakeel Butt , Jeremy Linton , Subject: Re: [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock Message-Id: <20220203151912.87d47b82c1bc3f0d56be0e3a@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: nil X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 359AB40002 X-Stat-Signature: dhoque15yzjzf97si388muypddmt4hue Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=CjspKTS1; dmarc=none; spf=pass (imf07.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1643930356-156534 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 Tue, 1 Feb 2022 14:33:04 -0800 Roman Gushchin wrote: > Alexander reported a circular lock dependency revealed by the mmap1 > ltp test: > LOCKDEP_CIRCULAR (suite: ltp, case: mtest06 (mmap1)) > > ... > > Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") I'm thinking it needs cc:stable. It sounds unlikely that we'll hit it in real life, but lockdep splats are concerning and I expect downstream kernel consumers will end up merging this anyway, for this reason.