4.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dave Young <dyoung@xxxxxxxxxx>
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 <sd@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Fixes: 7b0a911478c7 ("efi/x86: Move the EFI BGRT init code to early init code")
Link: http://lkml.kernel.org/r/20170526113652.21339-6-matt@xxxxxxxxxxxxxxxxxxx
[ Rewrote the changelog to be more readable. ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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));