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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53FF5C4332F for ; Fri, 18 Nov 2022 09:19:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241648AbiKRJT6 (ORCPT ); Fri, 18 Nov 2022 04:19:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241891AbiKRJTd (ORCPT ); Fri, 18 Nov 2022 04:19:33 -0500 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26AEB167CE for ; Fri, 18 Nov 2022 01:19:32 -0800 (PST) Received: by mail-wr1-x42c.google.com with SMTP id g12so8274738wrs.10 for ; Fri, 18 Nov 2022 01:19:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=ywmGO6HZoPeDk5pta/Zgi0l/H8NSLfPp6KexyZfvyDg=; b=XPRDdbxSOzJuW1tJt8/WHHpRnL8IMglbnT7xSVVogruEXcIywo6nDWDMXJnhsh0Til +nQRhwutmq5nZmv8aI9NOzyY7aB/KemObkTtxVM8iPd54uYQwHa5VhbuNEG9JdA0/SrL FtFdJhWtJBOqEGSYQiJHuSZPgdwXaf49DGFIzFP7h9d3Ht6cLtqQsnN0EvnpT/jWWLOp U53ZDhnVotci6ISnopHFOrEe3RpHuPBKHfX+fFnHH/H4x4eDlURpDi2FoNBvgeFugSCo 2VU81DsEDzHP38mJ3akPjnbGRTBIKdmpcIKti0fFUr6f6iilXuI6bF572+m+jUp+zKMY eMYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ywmGO6HZoPeDk5pta/Zgi0l/H8NSLfPp6KexyZfvyDg=; b=eWvg4txfLPzlPPRj4/jeUVdj4+ho774G+fXnOjuvs7rIWJbSzdumT7F3oXMSdA4f/2 wyNFm1TM1wn03RM+B2GNAWTpMdWpgq/oxCIK1YsAm9WCpT6c7a+hu3Cj5OYV8v8L4sLx hjXvOsdlIUSKEYrgnxZ6ZTqkJtaP/0IrCetSfxR2JmjZqk/iX+HoVchM1OXHHd57KDO8 garPrgccPtE32/bQ7jod6VZzPPyrIIyJTiBQS8ZLCIgj4jEK0LoyqZyAJifLXMxUxAWU mgT0ftvhBFOe9AkQHZVmVvHfv44kn1HUZYVqyIUhVZbaGBm9RHxSc1kRlbKwSugip8YD u/nA== X-Gm-Message-State: ANoB5pnmsJjKSFJ+QwpESFyzztPNceM8S7xZdkUBmbqOmppY5oQVgBtj Vf3NThrBBVkwL4sB+O09CXIW3w== X-Google-Smtp-Source: AA0mqf4IvIt8ecYfLqqdpfe2Ie8mTRQ05q6WdL2M9MInxr9ONrK62RPNSh4FwljtDFBhkb48MVrNJQ== X-Received: by 2002:a5d:53cd:0:b0:231:355b:211c with SMTP id a13-20020a5d53cd000000b00231355b211cmr3562614wrw.509.1668763170487; Fri, 18 Nov 2022 01:19:30 -0800 (PST) Received: from elver.google.com ([2a00:79e0:9c:201:4799:a943:410e:976]) by smtp.gmail.com with ESMTPSA id l8-20020adfa388000000b002417f35767asm3200743wrb.40.2022.11.18.01.19.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Nov 2022 01:19:29 -0800 (PST) Date: Fri, 18 Nov 2022 10:19:24 +0100 From: Marco Elver To: Dave Hansen Cc: Naresh Kamboju , Peter Zijlstra , kasan-dev , X86 ML , open list , linux-mm , regressions@lists.linux.dev, lkft-triage@lists.linaro.org, Andrew Morton , Alexander Potapenko Subject: Re: WARNING: CPU: 0 PID: 0 at arch/x86/include/asm/kfence.h:46 kfence_protect Message-ID: References: <4208866d-338f-4781-7ff9-023f016c5b07@intel.com> <41ac24c4-6c95-d946-2679-c1be2cb20536@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41ac24c4-6c95-d946-2679-c1be2cb20536@intel.com> User-Agent: Mutt/2.2.7 (2022-08-07) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 17, 2022 at 03:54PM -0800, Dave Hansen wrote: > On 11/17/22 15:23, Marco Elver wrote: > > Yes - it's the 'level != PG_LEVEL_4K'. > > That plus the bisect made it pretty easy to find, thanks for the effort! > > Could you double-check that the attached patch fixes it? It seemed to > for me. Yes, that works - thanks! > The issue was that the new "No changes, easy!" check in the suspect > commit didn't check the cpa->force_split option. It didn't split down > to 4k and then all hell broke loose. > > Oh, and I totally misread the kfence ability to tolerate partial TLB > flushes. Sorry for the noise there! > diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c > index 220361ceb997..9b4e2ad957f6 100644 > --- a/arch/x86/mm/pat/set_memory.c > +++ b/arch/x86/mm/pat/set_memory.c > @@ -1727,7 +1727,8 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int primary) > /* > * No changes, easy! > */ > - if (!(pgprot_val(cpa->mask_set) | pgprot_val(cpa->mask_clr))) > + if (!(pgprot_val(cpa->mask_set) | pgprot_val(cpa->mask_clr)) > + && !cpa->force_split) > return ret; > > while (rempages) { Tested-by: Marco Elver