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 B46F6C4332F for ; Thu, 17 Nov 2022 23:54:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232026AbiKQXyp (ORCPT ); Thu, 17 Nov 2022 18:54:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233266AbiKQXyl (ORCPT ); Thu, 17 Nov 2022 18:54:41 -0500 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16A2BB7ED for ; Thu, 17 Nov 2022 15:54:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668729281; x=1700265281; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to; bh=ifNgXix6UY+4zxJYIfL1i9Cvl28acOJnPFX6Dwbdguc=; b=NYCzhENBnb4LjAWuEeQZwy3teGC1MQlHsjJ5thD5wmKpbmusknXlCH+a AxFOYB1M/NtGmfV6xysCirOjQsceFBE2+mq/bv4X3cKbB188y7h/9CAmW dFQszLIB0XjtbRozBxZIi2r9wHIkGr0wN/QW6wCNr+4/XYxRtnD9GvdqY Pq0jKad2dImD3PAGl0bFvHjUt/UGRBqzcUpXSstyTTj78YEEQSXHvoIi1 o116zQN53tyP3Nz2jhSAg7uInf30VIBLuL0sGHLYL+cc1H2BselIOfwgL B3cNB91rv/wb9Ebh93/W+d1MKVdY20bNBokgK7FZBUeQ/tUbqkurHQxsO Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="292709623" X-IronPort-AV: E=Sophos;i="5.96,172,1665471600"; d="scan'208";a="292709623" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2022 15:54:23 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="703530903" X-IronPort-AV: E=Sophos;i="5.96,172,1665471600"; d="scan'208";a="703530903" Received: from vrgatne-mobl4.amr.corp.intel.com (HELO [10.209.115.197]) ([10.209.115.197]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2022 15:54:22 -0800 Content-Type: multipart/mixed; boundary="------------Lh9aXApYj7BdK6v1bd25dwlY" Message-ID: <41ac24c4-6c95-d946-2679-c1be2cb20536@intel.com> Date: Thu, 17 Nov 2022 15:54:21 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: WARNING: CPU: 0 PID: 0 at arch/x86/include/asm/kfence.h:46 kfence_protect Content-Language: en-US To: Marco Elver 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 References: <4208866d-338f-4781-7ff9-023f016c5b07@intel.com> From: Dave Hansen In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------Lh9aXApYj7BdK6v1bd25dwlY Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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. 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! --------------Lh9aXApYj7BdK6v1bd25dwlY Content-Type: text/x-patch; charset=UTF-8; name="kfence.patch" Content-Disposition: attachment; filename="kfence.patch" Content-Transfer-Encoding: base64 ZGlmZiAtLWdpdCBhL2FyY2gveDg2L21tL3BhdC9zZXRfbWVtb3J5LmMgYi9hcmNoL3g4Ni9t bS9wYXQvc2V0X21lbW9yeS5jCmluZGV4IDIyMDM2MWNlYjk5Ny4uOWI0ZTJhZDk1N2Y2IDEw MDY0NAotLS0gYS9hcmNoL3g4Ni9tbS9wYXQvc2V0X21lbW9yeS5jCisrKyBiL2FyY2gveDg2 L21tL3BhdC9zZXRfbWVtb3J5LmMKQEAgLTE3MjcsNyArMTcyNyw4IEBAIHN0YXRpYyBpbnQg X19jaGFuZ2VfcGFnZV9hdHRyX3NldF9jbHIoc3RydWN0IGNwYV9kYXRhICpjcGEsIGludCBw cmltYXJ5KQogCS8qCiAJICogTm8gY2hhbmdlcywgZWFzeSEKIAkgKi8KLQlpZiAoIShwZ3By b3RfdmFsKGNwYS0+bWFza19zZXQpIHwgcGdwcm90X3ZhbChjcGEtPm1hc2tfY2xyKSkpCisJ aWYgKCEocGdwcm90X3ZhbChjcGEtPm1hc2tfc2V0KSB8IHBncHJvdF92YWwoY3BhLT5tYXNr X2NscikpCisJICAgICYmICFjcGEtPmZvcmNlX3NwbGl0KQogCQlyZXR1cm4gcmV0OwogCiAJ d2hpbGUgKHJlbXBhZ2VzKSB7Cg== --------------Lh9aXApYj7BdK6v1bd25dwlY--