From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932649AbbKDKrX (ORCPT ); Wed, 4 Nov 2015 05:47:23 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:38451 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932340AbbKDKrU (ORCPT ); Wed, 4 Nov 2015 05:47:20 -0500 From: Matt Fleming To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Matt Fleming , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Andy Lutomirski , Borislav Petkov , "Huang, Ying" , Laszlo Ersek , Paolo Bonzini , stable@vger.kernel.org Subject: [GIT PULL] EFI urgent fix Date: Wed, 4 Nov 2015 10:47:16 +0000 Message-Id: <1446634037-10251-1-git-send-email-matt@codeblueprint.co.uk> X-Mailer: git-send-email 2.6.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Folks, the LKP robot reported an issue with Paolo's recent bug fix that syncs the identity mapping in 'initial_page_table'. Turns out that KERNEL_PGD_PTRS is not the correct constant to use when copying to the lower region because that's every PGD from PAGE_OFFSET to the end of the addressable memory. Crucially, KERNEL_PGD_PTRS > KERNEL_PGD_BOUNDARY and so the patch ends up trashing some of the kernel mappings in 'initial_page'table, leading to boot crashes on 32-bit SMP when bringing APs online. The following changes since commit 9ee870feaa9e0c6abef95a3b1fc518d88adfa2d3: Merge branch 'x86/cpufeature' into x86/urgent, to pick up pending Intel MID change (2015-11-03 12:00:40 +0100) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git tags/efi-urgent for you to fetch changes up to 5965d1bbeba70fe3626e4537f4729283cb0e75f7: x86/setup: Fix recent boot crash on 32-bit SMP machines (2015-11-04 09:26:24 +0000) ---------------------------------------------------------------- * Avoid trashing the kernel mappings in 'initial_page_table' when copying the identity mapping from 'swapper_pg_dir'. This bug was introduced by a bug fix in v4.3 which erroneously copies too many entries from 'swapper_pg_dir'. ---------------------------------------------------------------- Matt Fleming (1): x86/setup: Fix recent boot crash on 32-bit SMP machines arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: [GIT PULL] EFI urgent fix Date: Wed, 4 Nov 2015 10:47:16 +0000 Message-ID: <1446634037-10251-1-git-send-email-matt@codeblueprint.co.uk> Return-path: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Matt Fleming , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andy Lutomirski , Borislav Petkov , "Huang, Ying" , Laszlo Ersek , Paolo Bonzini , stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-efi@vger.kernel.org Folks, the LKP robot reported an issue with Paolo's recent bug fix that syncs the identity mapping in 'initial_page_table'. Turns out that KERNEL_PGD_PTRS is not the correct constant to use when copying to the lower region because that's every PGD from PAGE_OFFSET to the end of the addressable memory. Crucially, KERNEL_PGD_PTRS > KERNEL_PGD_BOUNDARY and so the patch ends up trashing some of the kernel mappings in 'initial_page'table, leading to boot crashes on 32-bit SMP when bringing APs online. The following changes since commit 9ee870feaa9e0c6abef95a3b1fc518d88adfa2d3: Merge branch 'x86/cpufeature' into x86/urgent, to pick up pending Intel MID change (2015-11-03 12:00:40 +0100) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git tags/efi-urgent for you to fetch changes up to 5965d1bbeba70fe3626e4537f4729283cb0e75f7: x86/setup: Fix recent boot crash on 32-bit SMP machines (2015-11-04 09:26:24 +0000) ---------------------------------------------------------------- * Avoid trashing the kernel mappings in 'initial_page_table' when copying the identity mapping from 'swapper_pg_dir'. This bug was introduced by a bug fix in v4.3 which erroneously copies too many entries from 'swapper_pg_dir'. ---------------------------------------------------------------- Matt Fleming (1): x86/setup: Fix recent boot crash on 32-bit SMP machines arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)