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 5097DC04A95 for ; Mon, 26 Sep 2022 00:10:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229655AbiIZAK1 (ORCPT ); Sun, 25 Sep 2022 20:10:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229605AbiIZAK0 (ORCPT ); Sun, 25 Sep 2022 20:10:26 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D550C24BD1; Sun, 25 Sep 2022 17:10:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664151024; x=1695687024; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=47gt1TEuPE8j169uNoQ5XLe249DFPFUls31iYOWmThs=; b=EzYCOOtDhjk5Tp9vv03jwRek3NmJNCZ7PNGBQAzVeQy21e3WpCRx6MHg 9sCac9XY7zjP4HnZTrjg1aCOrJJn9NOLb2f3cqWLgNJ6cVzHGSAOQEVTA kH6TgGTSgxGgVz0LonweFMyvhhL9a8kTkc5S9FAx49bC528adrkthN+6k I0pDqr79XmviKJBl/UNNZ5bV11Qf+sQTunUyjZu/fjQE7S6KXo3w0jssI Ifgkk+LzxNLtqehcqwb+9aHtheigxRLeU3Xu43GO3OBXapi08aRO1L4TJ Vckjdy1LxRNeFUO+SHRHczy7ItXseOwFjot93Qytl0e6KCeZrFybBPSfQ w==; X-IronPort-AV: E=McAfee;i="6500,9779,10481"; a="364938685" X-IronPort-AV: E=Sophos;i="5.93,345,1654585200"; d="scan'208";a="364938685" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Sep 2022 17:10:23 -0700 X-IronPort-AV: E=Sophos;i="5.93,345,1654585200"; d="scan'208";a="763247523" Received: from obyrd-mobl2.amr.corp.intel.com (HELO [10.212.210.57]) ([10.212.210.57]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Sep 2022 17:10:21 -0700 Message-ID: Date: Sun, 25 Sep 2022 17:10:19 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [syzbot] WARNING in __change_page_attr_set_clr Content-Language: en-US To: Alexei Starovoitov , Linus Torvalds , tech-board@lists.linuxfoundation.org, Song Liu , Kernel Team Cc: Borislav Petkov , brijesh.singh@amd.com, Dan Williams , Dave Hansen , "H. Peter Anvin" , jane.chu@oracle.com, "Kirill A. Shutemov" , LKML , Andy Lutomirski , Ingo Molnar , Peter Zijlstra , seanjc@google.com, syzkaller-bugs , Thomas Gleixner , Tom Lendacky , X86 ML , Alexei Starovoitov , Daniel Borkmann , John Fastabend , "open list:BPF (Safe dynamic programs and tools)" References: <00000000000076f3a305e97e9229@google.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 9/25/22 14:55, Alexei Starovoitov wrote: > And, sorry, "flip ro/rw every time" is not a good idea from > security pov. > There is a much better solution that stalled on the code review. > In the meantime we'll land a quick fix to re-enable boot in -next > in the coming days. Peter, I remember an earlier version of your patch having some various enforcement modes. Since the strict enforcement has actually broken a few things, should we resurrect the nicer soft detection mode? Or, maybe make the soft one the only mode for now? Alexei, the "quick fix" looks sane to me at first glance. Is there something in there that's not viable long-term? Also, the intention here was not to force any issues. I thought the earlier discussion resulted in a bpf fix and applying Peter's patch was intended to catch _future_ issues. I should have double-checked before applying it. My apologies.