Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753053AbdFLP2u (ORCPT ); Mon, 12 Jun 2017 11:28:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39688 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752991AbdFLP2s (ORCPT ); Mon, 12 Jun 2017 11:28:48 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sabrina Dubroca , Dave Young , Ard Biesheuvel , Matt Fleming , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-efi@vger.kernel.org, Ingo Molnar Subject: [PATCH 4.11 049/150] efi/bgrt: Skip efi_bgrt_init() in case of non-EFI boot Date: Mon, 12 Jun 2017 17:24:16 +0200 Message-Id: <20170612152521.552786146@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170612152519.404936272@linuxfoundation.org> References: <20170612152519.404936272@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: 1957 Lines: 60 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Young commit 7425826f4f7ac60f2538b06a7f0a5d1006405159 upstream. Sabrina Dubroca reported an early panic: BUG: unable to handle kernel paging request at ffffffffff240001 IP: efi_bgrt_init+0xdc/0x134 [...] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ... which was introduced by: 7b0a911478c7 ("efi/x86: Move the EFI BGRT init code to early init code") The cause is that on this machine the firmware provides the EFI ACPI BGRT table even on legacy non-EFI bootups - which table should be EFI only. The garbage BGRT data causes the efi_bgrt_init() panic. Add a check to skip efi_bgrt_init() in case non-EFI bootup to work around this firmware bug. Tested-by: Sabrina Dubroca Signed-off-by: Dave Young Signed-off-by: Ard Biesheuvel Signed-off-by: Matt Fleming Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: 7b0a911478c7 ("efi/x86: Move the EFI BGRT init code to early init code") Link: http://lkml.kernel.org/r/20170526113652.21339-6-matt@codeblueprint.co.uk [ Rewrote the changelog to be more readable. ] Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/platform/efi/efi-bgrt.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/platform/efi/efi-bgrt.c +++ b/arch/x86/platform/efi/efi-bgrt.c @@ -36,6 +36,9 @@ void __init efi_bgrt_init(struct acpi_ta if (acpi_disabled) return; + if (!efi_enabled(EFI_BOOT)) + return; + if (table->length < sizeof(bgrt_tab)) { pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n", table->length, sizeof(bgrt_tab));