4.11-stable review patch. If anyone has any objections, please let me know.
------------------ From: Dave Young <dyo...@redhat.com> 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 <s...@queasysnail.net> Signed-off-by: Dave Young <dyo...@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> Signed-off-by: Matt Fleming <m...@codeblueprint.co.uk> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> 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-m...@codeblueprint.co.uk [ Rewrote the changelog to be more readable. ] Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- 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)); -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html