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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6EE17C433F5 for ; Fri, 15 Oct 2021 08:27:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5687660249 for ; Fri, 15 Oct 2021 08:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232842AbhJOI3d (ORCPT ); Fri, 15 Oct 2021 04:29:33 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:42144 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234200AbhJOI3Y (ORCPT ); Fri, 15 Oct 2021 04:29:24 -0400 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-out1.suse.de (Postfix) with ESMTPS id DA3BC2196D; Fri, 15 Oct 2021 08:27:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1634286437; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XH1hXLqLnxkTOtk+fqniTFsoIzBDMQNj7gJXWTZhb68=; b=jTXff+NMj4KD+TPpQ+au1XtLgKxtztE7sl4HB7sergBRGa9YK94vEEQZrKw+RxZuAWE8Cv VDYramXzOdK7OdMM5EAOzc3Kib/P2ysbmXsBpCwA4/982L3XG2fWGjtgYKkPWJALlFACg/ 48X2R8E4Y/zC4FNoK0BWli6e307iHT0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1634286437; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XH1hXLqLnxkTOtk+fqniTFsoIzBDMQNj7gJXWTZhb68=; b=uGC9lMi8Azr/5HCWiZsASoGhDPKCA28O9ceP3c8nt+FWh/BCJPe7hEC0Owi/vo8JiM2QAH XuA7L7dyGqWV80Cw== 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 838AE13B87; Fri, 15 Oct 2021 08:27:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id DTlAH2U7aWHKCQAAMHmgww (envelope-from ); Fri, 15 Oct 2021 08:27:17 +0000 Message-ID: <137e4211-266f-bdb3-6830-e101c27c3be4@suse.cz> Date: Fri, 15 Oct 2021 10:27:17 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [lib/stackdepot] 1cd8ce52c5: BUG:unable_to_handle_page_fault_for_address Content-Language: en-US To: Mike Rapoport Cc: kernel test robot , 0day robot , Dmitry Vyukov , Marco Elver , Vijayanand Jitta , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Geert Uytterhoeven , Oliver Glitta , Imran Khan , LKML , lkp@lists.01.org, Andrew Morton , linux-mm@kvack.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kasan-dev@googlegroups.com References: <20211014085450.GC18719@xsang-OptiPlex-9020> <4d99add1-5cf7-c608-a131-18959b85e5dc@suse.cz> From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/14/21 12:16, Mike Rapoport wrote: > On Thu, Oct 14, 2021 at 11:33:03AM +0200, Vlastimil Babka wrote: >> On 10/14/21 10:54, kernel test robot wrote: >> >> In my local testing of the patch, when stackdepot was initialized through >> page owner init, it was using kvmalloc() so slab_is_available() was true. >> Looks like the exact order of slab vs page_owner alloc is non-deterministic, >> could be arch-dependent or just random ordering of init calls. A wrong order >> will exploit the apparent fact that slab_is_available() is not a good >> indicator of using memblock vs page allocator, and we would need a better one. >> Thoughts? > > The order of slab vs page_owner is deterministic, but it is different for > FLATMEM and SPARSEMEM. And page_ext_init_flatmem_late() that initializes > page_ext for FLATMEM is called exactly between buddy and slab setup: Oh, so it was due to FLATMEM, thanks for figuring that out! > static void __init mm_init(void) > { > ... > > mem_init(); > mem_init_print_info(); > /* page_owner must be initialized after buddy is ready */ > page_ext_init_flatmem_late(); > kmem_cache_init(); > > ... > } > > I've stared for a while at page_ext init and it seems that the > page_ext_init_flatmem_late() can be simply dropped because there is anyway > a call to invoke_init_callbacks() in page_ext_init() that is called much > later in the boot process. Yeah, but page_ext_init() only does something for SPARSEMEM, and is empty on FLATMEM. Otherwise it would be duplicating all the work. So I'll just move page_ext_init_flatmem_late() below kmem_cache_init() in mm_init(). Thanks again!