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 405A4C433EF for ; Mon, 28 Feb 2022 16:28:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA8BB8D0002; Mon, 28 Feb 2022 11:28:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B57D18D0001; Mon, 28 Feb 2022 11:28:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A20338D0002; Mon, 28 Feb 2022 11:28:26 -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 938268D0001 for ; Mon, 28 Feb 2022 11:28:26 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 61E2B215ED for ; Mon, 28 Feb 2022 16:28:26 +0000 (UTC) X-FDA: 79192721412.06.DE38CF8 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) by imf12.hostedemail.com (Postfix) with ESMTP id EF73440009 for ; Mon, 28 Feb 2022 16:28:25 +0000 (UTC) Received: by mail-wm1-f49.google.com with SMTP id bg16-20020a05600c3c9000b00380f6f473b0so6071555wmb.1 for ; Mon, 28 Feb 2022 08:28:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=BliGt+iPKuKGr4oLeNuQ/K/5nXnK23JHVRrUdB5Tty4=; b=Mt08F5B/Al0+2RudF6JL95dKNQ9fFfqz++XHh5fxjmdL6aF8yCVa63qI0wDVf5YH8F D2ZiWA8rZgPHTk9YYdYriyerp6DCVt33b+ORMLpXY++8MNmjhlqL4eXMVVsEF386UFZc C+7zaRsYrCbzTEgc9YmkaPtHWAcw90x7Fz7wk33Dl+VomcnbPiW35/ZCjDjfdUC2Lu7o 3qBrQSpnSbwaMS8bBInqDjX4r86wxiOQXMjLT7EJd/0FA0eoAKU+7Nl+HqqpR/EqUHnk tCzc8hHUW8vIb7CWEgE31naKa42QlYbyHYnmGQBs2zXeJI+x6OE/HdeZwEyr3UEk05FI yzmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=BliGt+iPKuKGr4oLeNuQ/K/5nXnK23JHVRrUdB5Tty4=; b=h5ctLjZmnD40TZfz/5+F1hobExE9OeFK7MaS29pPcFyhIdr99AXx/Rp9BoBDAhW/zv 84dM9JtGY9r9sM4zE2HBHSDs9KYThQpd0hk520H1WBW2wqDuQ6PxU9V7sFNW8t14PRav uw0BYI5kGWUsRjeIhEq1roMvmT4momzbQco96tplWqDPOPlKX26R0RWXsI52SQ+mGayU rH369bB1q+4+Ehi+l/orZ2Yi8N8N6yK0VF/RZQp/OzR1GHNxnSQcrtRb+49JhCEVY+qk fbvd0QvUAWNL9D74u+Y/2zuDHBWQ+8/nxFpyWHxQPtS2jaKinYJebFNT4QHUiXf+IMJW Yn/A== X-Gm-Message-State: AOAM531GPJR+jkyePQRbnS1HkmQrd3g7bDHeE5enI2S2C1Ngqks+Gzh1 6BWy53sISt9VjbCUKXjnSdTaCg== X-Google-Smtp-Source: ABdhPJxZIvUBldRsZFQEsWiZZluxxoz8ubHo63gOYgUKw80pFb+R/RqQoRzJITseDXlGGvaxWo6/4Q== X-Received: by 2002:a7b:c381:0:b0:37b:e01f:c1c0 with SMTP id s1-20020a7bc381000000b0037be01fc1c0mr13771904wmj.98.1646065704302; Mon, 28 Feb 2022 08:28:24 -0800 (PST) Received: from elver.google.com ([2a00:79e0:15:13:4ba9:ec5e:bee2:4388]) by smtp.gmail.com with ESMTPSA id e22-20020adf9bd6000000b001eda1017861sm11422337wrc.64.2022.02.28.08.28.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Feb 2022 08:28:23 -0800 (PST) Date: Mon, 28 Feb 2022 17:28:17 +0100 From: Marco Elver To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Vlastimil Babka , David Rientjes , Christoph Lameter , Joonsoo Kim , Pekka Enberg , Roman Gushchin , Andrew Morton , linux-mm@kvack.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, Oliver Glitta , Faiyaz Mohammed , Dmitry Vyukov , Eric Dumazet , Jarkko Sakkinen , Johannes Berg , Yury Norov , Arnd Bergmann , James Bottomley , Matteo Croce , Andrey Konovalov , Imran Khan , Zqiang Subject: Re: [PATCH] mm/slub: initialize stack depot in boot process Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.1.4 (2021-12-11) X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EF73440009 X-Stat-Signature: 673zkhri7a8hik8oqk5mwo6j3k5fa77h Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="Mt08F5B/"; spf=pass (imf12.hostedemail.com: domain of elver@google.com designates 209.85.128.49 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-HE-Tag: 1646065705-947095 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 Mon, Feb 28, 2022 at 03:09PM +0000, Hyeonggon Yoo wrote: > commit ba10d4b46655 ("mm/slub: use stackdepot to save stack trace in > objects") initializes stack depot while creating cache if SLAB_STORE_USER > flag is set. > > This can make kernel crash because a cache can be created in various > contexts. For example if user sets slub_debug=U, kernel crashes > because create_boot_cache() calls stack_depot_init(), which tries to > allocate hash table using memblock_alloc() if slab is not available. > But memblock is also not available at that time. > > This patch solves the problem by initializing stack depot early > in boot process if SLAB_STORE_USER debug flag is set globally > or the flag is set to at least one cache. > > [ elver@google.com: initialize stack depot depending on slub_debug > parameter instead of allowing stack_depot_init() can be called > in kmem_cache_init() for simplicity. ] > > Link: https://lkml.org/lkml/2022/2/28/238 This would be a better permalink: https://lore.kernel.org/all/YhyeaP8lrzKgKm5A@ip-172-31-19-208.ap-northeast-1.compute.internal/ > Fixes: ba10d4b46655 ("mm/slub: use stackdepot to save stack trace in objects") This commit does not exist in -next. I assume you intend that "lib/stackdepot: Use page allocator if both slab and memblock is unavailable" should be dropped now. > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > --- > include/linux/slab.h | 1 + > init/main.c | 1 + > mm/slab.c | 4 ++++ > mm/slob.c | 4 ++++ > mm/slub.c | 28 +++++++++++++++++++++++++--- > 5 files changed, 35 insertions(+), 3 deletions(-) [...] > > +/* Initialize stack depot if needed */ > +void __init kmem_cache_init_early(void) > +{ > +#ifdef CONFIG_STACKDEPOT > + slab_flags_t block_flags; > + char *next_block; > + char *slab_list; > + > + if (slub_debug & SLAB_STORE_USER) > + goto init_stack_depot; > + > + next_block = slub_debug_string; > + while (next_block) { > + next_block = parse_slub_debug_flags(next_block, &block_flags, &slab_list, false); > + if (block_flags & SLAB_STORE_USER) > + goto init_stack_depot; > + } > + > + return; > + > +init_stack_depot: > + stack_depot_init(); > +#endif > +} You can simplify this function to avoid the goto: /* Initialize stack depot if needed */ void __init kmem_cache_init_early(void) { #ifdef CONFIG_STACKDEPOT slab_flags_t flags = slub_debug; char *next_block = slub_debug_string; char *slab_list; for (;;) { if (flags & SLAB_STORE_USER) { stack_depot_init(); break; } if (!next_block) break; next_block = parse_slub_debug_flags(next_block, &flags, &slab_list, false); } #endif } ^^ with this version, it'd also be much easier and less confusing to add other initialization logic unrelated to stackdepot later after the loop (should it ever be required).