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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB454C74A22 for ; Wed, 10 Jul 2019 13:31:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A208A2064B for ; Wed, 10 Jul 2019 13:31:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=mengyan1223.wang header.i=@mengyan1223.wang header.b="mqTkj8cj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727255AbfGJNbo (ORCPT ); Wed, 10 Jul 2019 09:31:44 -0400 Received: from mengyan1223.wang ([89.208.246.23]:38742 "EHLO mengyan1223.wang" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725994AbfGJNbn (ORCPT ); Wed, 10 Jul 2019 09:31:43 -0400 Received: from xry111-laptop.lan (unknown [124.115.222.149]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client did not present a certificate) (Authenticated sender: xry111@mengyan1223.wang) by mengyan1223.wang (Postfix) with ESMTPSA id 6FA9465B50; Wed, 10 Jul 2019 09:31:39 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mengyan1223.wang; s=mail; t=1562765502; bh=+kX+n3hyhZoLMZ3AyyBvfYkQJJMtdOnst/LvSxzqXpA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=mqTkj8cjCJmnvx6exJv6Jpz9ro4dHyALrUSIGQySKxAAK7oXDazA9KzbOLauSQMMB 0W2qeRP2dxg1GG66cITqO2o+0b1cOJFAvl3CFRhQipG08u9LUa0B1OnV5wAOeVPs3+ MF4UV95XoZiUua8QoDJ/NjMogP9j4p8QwloD15BADBa5akXtZQRI9ONv5p+t0/+bJs M1Hy+GMkYv8bwtrWNBD3a8Kgbnq8m5/jUWhCIuoV/ICvmWx0ut4oK/s+hpC4LKlzNI RRe7LFprMh0bRG3g7bNhxZLAJDlKOshI9UowljkV8z7/QZ0WSoesbEcRkqLvQYgpIB sR5d0pIKH1Yzg== Message-ID: <4f0e830430f46c5f6b90656ec5d3b969d79fe6db.camel@mengyan1223.wang> Subject: Re: [GIT PULL] x86/topology changes for v5.3 From: Xi Ruoyao To: Jiri Kosina , Peter Zijlstra Cc: Thomas Gleixner , Kees Cook , Linus Torvalds , Ingo Molnar , Linux List Kernel Mailing , Borislav Petkov , Len Brown , Andrew Morton , "Rafael J. Wysocki" , Tony Luck , Bob Moore , Erik Schmauss , Josh Poimboeuf , Daniel Bristot de Oliveira Date: Wed, 10 Jul 2019 21:31:35 +0800 In-Reply-To: References: <201907091727.91CC6C72D8@keescook> <1ad2de95e694a29909801d022fe2d556df9a4bd5.camel@mengyan1223.wang> <20190710132144.GM3402@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.3 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-07-10 15:28 +0200, Jiri Kosina wrote: > On Wed, 10 Jul 2019, Jiri Kosina wrote: > > > > > BUG: unable to handle page fault for address: ffffffff9edc1598 > > > > > #PF: supervisor write access in kernel mode > > > > > #PF: error_code(0x0003) - permissions violation > > Hm, and it seems to explode on dereferencing the static_key* in %rsi > > ^^^ %rdi of > course > > > 21: 48 8b 37 mov (%rdi),%rsi > > 24: 83 e6 03 and $0x3,%esi > > 27: 48 09 c6 or %rax,%rsi > > 2a:* 48 89 37 mov %rsi,(%rdi) <-- trapping > > instruction > > > > which looks odd, as it derefenced it successfully just 3 instructions ago. It seems the MMU (I guess ?) allows to read it, but disallows to write it: "supervisor write access in kernel mode". -- Xi Ruoyao School of Aerospace Science and Technology, Xidian University