From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 783478C1F; Wed, 20 Sep 2023 08:43:59 +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-out2.suse.de (Postfix) with ESMTPS id A55041FDDA; Wed, 20 Sep 2023 08:43:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1695199437; 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=GjxBNZGORuJZTEppU8GKxjtCs5dciR43Qw/lEOGS50I=; b=EQnrAlU/3fuFatTWKEmawTXMpJeQzH/U6qvScECWhU41Pu6gX6JI12bG3Nr+YOhd9n7IOo q8G2eBepsmnJIuhaaiZ09mWIDB/3QPPqGQwfCCcOqZZEnyN5J9MY7jj18kpt1ks8tb3pEO K+ubfa53ezr2wkkyOZuUPYWxTXmLf34= 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 7EDBD132C7; Wed, 20 Sep 2023 08:43:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ZkT2G82wCmWvXQAAMHmgww (envelope-from ); Wed, 20 Sep 2023 08:43:57 +0000 Date: Wed, 20 Sep 2023 10:43:56 +0200 From: Michal Hocko To: Jeremi Piotrowski Cc: Greg Kroah-Hartman , stable@vger.kernel.org, patches@lists.linux.dev, Shakeel Butt , Johannes Weiner , Roman Gushchin , Muchun Song , Tejun Heo , Andrew Morton , linux-kernel@vger.kernel.org, regressions@lists.linux.dev, mathieu.tortuyaux@gmail.com Subject: Re: [REGRESSION] Re: [PATCH 6.1 033/219] memcg: drop kmem.limit_in_bytes Message-ID: References: <20230917191040.964416434@linuxfoundation.org> <20230917191042.204185566@linuxfoundation.org> <20230920081101.GA12096@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230920081101.GA12096@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> On Wed 20-09-23 01:11:01, Jeremi Piotrowski wrote: > On Sun, Sep 17, 2023 at 09:12:40PM +0200, Greg Kroah-Hartman wrote: > > 6.1-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > Hi Greg/Michal, > > This commit breaks userspace which makes it a bad commit for mainline and an > even worse commit for stable. > > We ingested 6.1.54 into our nightly testing and found that runc fails to gather > cgroup statistics (when reading kmem.limit_in_bytes). The same code is vendored > into kubelet and kubelet fails to start if this operation fails. 6.1.53 is > fine. Could you expand some more on why is the file read? It doesn't support writing to it for some time so how does reading it helps in any sense? Anyway, I do agree that the stable backport should be reverted. > > Address this by wiping out the file completely and effectively get back to > > pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration. > > On reads, the runc code checks for MEMCG_KMEM=n by checking > kmem.usage_in_bytes. If it is present then runc expects the other cgroup files > to be there (including kmem.limit_in_bytes). So this change is not effectively > the same. > > Here's a link to the PR that would be needed to handle this change in userspace > (not merged yet and would need to be propagated through the ecosystem): > > https://github.com/opencontainers/runc/pull/4018. Thanks. Does that mean the revert is still necessary for the Linus tree or do you expect that the fix can be merged and propagated in a reasonable time? -- Michal Hocko SUSE Labs