From patchwork Mon Mar 15 15:34:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 12139869 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 1F611C433E0 for ; Mon, 15 Mar 2021 15:36:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE63A64E76 for ; Mon, 15 Mar 2021 15:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231578AbhCOPf7 (ORCPT ); Mon, 15 Mar 2021 11:35:59 -0400 Received: from mx2.suse.de ([195.135.220.15]:51336 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233668AbhCOPfp (ORCPT ); Mon, 15 Mar 2021 11:35:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8C8F8AC23; Mon, 15 Mar 2021 15:35:44 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Paul E . McKenney" , linux-btrfs@vger.kernel.org, David Sterba , Vlastimil Babka , Oliver Glitta Subject: [PATCH] [PATCH] mm, slub: enable slub_debug static key when creating cache with explicit debug flags Date: Mon, 15 Mar 2021 16:34:15 +0100 Message-Id: <20210315153415.24404-1-vbabka@suse.cz> X-Mailer: git-send-email 2.30.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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/ Reported-by: Oliver Glitta Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") Signed-off-by: Vlastimil Babka Acked-by: David Rientjes --- mm/slub.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 350a37f30e60..cd6694ad1a0a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3827,6 +3827,15 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags) { +#ifdef CONFIG_SLUB_DEBUG + /* + * If no slub_debug was enabled globally, the static key is not yet + * enabled by setup_slub_debug(). Enable it if the cache is being + * created with any of the debugging flags passed explicitly. + */ + if (flags & SLAB_DEBUG_FLAGS) + static_branch_enable(&slub_debug_enabled); +#endif s->flags = kmem_cache_flags(s->size, flags, s->name); #ifdef CONFIG_SLAB_FREELIST_HARDENED s->random = get_random_long();