Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753708AbdCPOg1 (ORCPT ); Thu, 16 Mar 2017 10:36:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:32930 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753683AbdCPOgX (ORCPT ); Thu, 16 Mar 2017 10:36:23 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ard Biesheuvel , Linus Torvalds , Matt Fleming , Peter Zijlstra , Thomas Gleixner , linux-efi@vger.kernel.org, Ingo Molnar Subject: [PATCH 4.10 19/48] efi/arm: Fix boot crash with CONFIG_CPUMASK_OFFSTACK=y Date: Thu, 16 Mar 2017 23:30:03 +0900 Message-Id: <20170316142921.749143958@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170316142920.761502205@linuxfoundation.org> References: <20170316142920.761502205@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1851 Lines: 59 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ard Biesheuvel commit d1eb98143c56f24fef125f5bbed49ae0b52fb7d6 upstream. On ARM and arm64, we use a dedicated mm_struct to map the UEFI Runtime Services regions, which allows us to map those regions on demand, and in a way that is guaranteed to be compatible with incoming kernels across kexec. As it turns out, we don't fully initialize the mm_struct in the same way as process mm_structs are initialized on fork(), which results in the following crash on ARM if CONFIG_CPUMASK_OFFSTACK=y is enabled: ... EFI Variables Facility v0.08 2004-May-17 Unable to handle kernel NULL pointer dereference at virtual address 00000000 [...] Process swapper/0 (pid: 1) ... __memzero() check_and_switch_context() virt_efi_get_next_variable() efivar_init() efivars_sysfs_init() do_one_initcall() ... This is due to a missing call to mm_init_cpumask(), so add it. Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1488395154-29786-1-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/efi/arm-runtime.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/firmware/efi/arm-runtime.c +++ b/drivers/firmware/efi/arm-runtime.c @@ -65,6 +65,7 @@ static bool __init efi_virtmap_init(void bool systab_found; efi_mm.pgd = pgd_alloc(&efi_mm); + mm_init_cpumask(&efi_mm); init_new_context(NULL, &efi_mm); systab_found = false;