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=-11.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 F27D4C31E4C for ; Fri, 14 Jun 2019 14:40:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAE052133D for ; Fri, 14 Jun 2019 14:40:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="dKcaYIc8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728912AbfFNOk1 (ORCPT ); Fri, 14 Jun 2019 10:40:27 -0400 Received: from terminus.zytor.com ([198.137.202.136]:37211 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728210AbfFNOk0 (ORCPT ); Fri, 14 Jun 2019 10:40:26 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x5EEeDX21735706 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Fri, 14 Jun 2019 07:40:13 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x5EEeDX21735706 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019051801; t=1560523213; bh=MTIomEjR0QGw2Y/B1esgMdBm8zLW2TjMINe9+/UbZw8=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=dKcaYIc8B3jJkXC26NehlU+BlKN/18Sn83o6rZT+Sgw0mA6B21TVcF3xeJu9xqNt2 LfszzEOdPOz2Ub7jkKtA1C9L1gPkForhBSv1j04JzzyHDnDovgEFpRASi9MagWMQ0R OZpgbiqpQxXQu5CHeK/T6C3/blbi4xw3aZbhhjj6TYhKZtvjLQfOaEBTV6J2SoOw7B 2CtOKJrPTvdeZmo76nvX7VmG+oW3MGAD93Q8lSULAPl6tikwyaAEex6K95ibsGYFO2 nbKitfAqr+BrmYxOMPIMnkgM4PfThQdVM/ibfQJ2MDTJvVCcbY9yFQE8d4PaaJj80J 6noge/6ltFrFg== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x5EEeCAi1735701; Fri, 14 Jun 2019 07:40:12 -0700 Date: Fri, 14 Jun 2019 07:40:12 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Andrey Ryabinin Message-ID: Cc: bp@alien8.de, linux-kernel@vger.kernel.org, mingo@kernel.org, dvyukov@google.com, tglx@linutronix.de, kirill@shutemov.name, stable@vger.kernel.org, aryabinin@virtuozzo.com, glider@google.com, hpa@zytor.com Reply-To: hpa@zytor.com, glider@google.com, stable@vger.kernel.org, aryabinin@virtuozzo.com, kirill@shutemov.name, tglx@linutronix.de, mingo@kernel.org, dvyukov@google.com, linux-kernel@vger.kernel.org, bp@alien8.de In-Reply-To: <20190614143149.2227-1-aryabinin@virtuozzo.com> References: <20190614143149.2227-1-aryabinin@virtuozzo.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/kasan: Fix boot with 5-level paging and KASAN Git-Commit-ID: f3176ec9420de0c385023afa3e4970129444ac2f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f3176ec9420de0c385023afa3e4970129444ac2f Gitweb: https://git.kernel.org/tip/f3176ec9420de0c385023afa3e4970129444ac2f Author: Andrey Ryabinin AuthorDate: Fri, 14 Jun 2019 17:31:49 +0300 Committer: Thomas Gleixner CommitDate: Fri, 14 Jun 2019 16:37:30 +0200 x86/kasan: Fix boot with 5-level paging and KASAN Since commit d52888aa2753 ("x86/mm: Move LDT remap out of KASLR region on 5-level paging") kernel doesn't boot with KASAN on 5-level paging machines. The bug is actually in early_p4d_offset() and introduced by commit 12a8cc7fcf54 ("x86/kasan: Use the same shadow offset for 4- and 5-level paging") early_p4d_offset() tries to convert pgd_val(*pgd) value to a physical address. This doesn't make sense because pgd_val() already contains the physical address. It did work prior to commit d52888aa2753 because the result of "__pa_nodebug(pgd_val(*pgd)) & PTE_PFN_MASK" was the same as "pgd_val(*pgd) & PTE_PFN_MASK". __pa_nodebug() just set some high bits which were masked out by applying PTE_PFN_MASK. After the change of the PAGE_OFFSET offset in commit d52888aa2753 __pa_nodebug(pgd_val(*pgd)) started to return a value with more high bits set and PTE_PFN_MASK wasn't enough to mask out all of them. So it returns a wrong not even canonical address and crashes on the attempt to dereference it. Switch back to pgd_val() & PTE_PFN_MASK to cure the issue. Fixes: 12a8cc7fcf54 ("x86/kasan: Use the same shadow offset for 4- and 5-level paging") Reported-by: Kirill A. Shutemov Signed-off-by: Andrey Ryabinin Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: kasan-dev@googlegroups.com Cc: stable@vger.kernel.org Cc: Link: https://lkml.kernel.org/r/20190614143149.2227-1-aryabinin@virtuozzo.com --- arch/x86/mm/kasan_init_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 8dc0fc0b1382..296da58f3013 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -199,7 +199,7 @@ static inline p4d_t *early_p4d_offset(pgd_t *pgd, unsigned long addr) if (!pgtable_l5_enabled()) return (p4d_t *)pgd; - p4d = __pa_nodebug(pgd_val(*pgd)) & PTE_PFN_MASK; + p4d = pgd_val(*pgd) & PTE_PFN_MASK; p4d += __START_KERNEL_map - phys_base; return (p4d_t *)p4d + p4d_index(addr); }