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 X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 264A4C2BA04 for ; Wed, 12 May 2021 19:23:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EEA3261418 for ; Wed, 12 May 2021 19:23:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379861AbhELTUX (ORCPT ); Wed, 12 May 2021 15:20:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:50920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244789AbhELQvL (ORCPT ); Wed, 12 May 2021 12:51:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 655A061D6B; Wed, 12 May 2021 16:18:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620836307; bh=L//eVip2ugc2dnjIBpAAQDQ5bs6VSLdTVlefG5+qRtA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PCahJ434qSX6HMll2gzCnwvtr9P7pgnLaS8yTWe/kfyDY35szSoSKBnIqQ8cTdZBP cHEZnJw9W2t7VFfSsTSt2yws2nHP3ji05EbvFHGz/c/OMDrLzrH/MMaHsWaXrH23RZ e675KJj4fAGjxjalactwCfv7C4MzdIeDJY90mtQ8= Date: Wed, 12 May 2021 17:50:31 +0200 From: Greg Kroah-Hartman To: Vlastimil Babka Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Oliver Glitta , David Rientjes , Christoph Lameter , Pekka Enberg , Joonsoo Kim , "Paul E. McKenney" , Andrew Morton , Linus Torvalds , Sasha Levin Subject: Re: [PATCH 5.10 518/530] mm, slub: enable slub_debug static key when creating cache with explicit debug flags Message-ID: References: <20210512144819.664462530@linuxfoundation.org> <20210512144836.780038842@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 12, 2021 at 05:35:28PM +0200, Vlastimil Babka wrote: > On 5/12/21 4:50 PM, Greg Kroah-Hartman wrote: > > From: Vlastimil Babka > > > > [ Upstream commit 1f0723a4c0df36cbdffc6fac82cd3c5d57e06d66 ] > > > > Commit ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") > > introduced a static key to optimize the case where no debugging is > > enabled for any cache. The static key is enabled when slub_debug boot > > parameter is passed, or CONFIG_SLUB_DEBUG_ON enabled. > > > > However, some caches might be created with one or more debugging flags > > explicitly passed to kmem_cache_create(), and the commit missed this. > > Thus the debugging functionality would not be actually performed for > > these caches unless the static key gets enabled by boot param or config. > > > > This patch fixes it by checking for debugging flags passed to > > kmem_cache_create() and enabling the static key accordingly. > > > > Note such explicit debugging flags should not be used outside of > > debugging and testing as they will now enable the static key globally. > > btrfs_init_cachep() creates a cache with SLAB_RED_ZONE but that's a > > mistake that's being corrected [1]. rcu_torture_stats() creates a cache > > with SLAB_STORE_USER, but that is a testing module so it's OK and will > > start working as intended after this patch. > > > > Also note that in case of backports to kernels before v5.12 that don't > > have 59450bbc12be ("mm, slab, slub: stop taking cpu hotplug lock"), > > static_branch_enable_cpuslocked() should be used. > > > > [1] https://lore.kernel.org/linux-btrfs/20210315141824.26099-1-dsterba@suse.com/ > > > > Link: https://lkml.kernel.org/r/20210315153415.24404-1-vbabka@suse.cz > > Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") > > Signed-off-by: Vlastimil Babka > > Reported-by: Oliver Glitta > > Acked-by: David Rientjes > > Cc: Christoph Lameter > > Cc: Pekka Enberg > > Cc: Joonsoo Kim > > Cc: "Paul E. McKenney" > > Signed-off-by: Andrew Morton > > Signed-off-by: Linus Torvalds > > Signed-off-by: Sasha Levin > > Uh, rather not release this to stable without the followup fix: > https://lore.kernel.org/linux-mm/20210504120019.26791-1-vbabka@suse.cz/ Is that in Linus's tree yet? If so, what is the git id? thanks, greg k-h