This is a note to let you know that I've just added the patch titled
efi/arm: Fix boot crash with CONFIG_CPUMASK_OFFSTACK=y
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
efi-arm-fix-boot-crash-with-config_cpumask_offstack-y.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d1eb98143c56f24fef125f5bbed49ae0b52fb7d6 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Date: Wed, 1 Mar 2017 19:05:54 +0000
Subject: efi/arm: Fix boot crash with CONFIG_CPUMASK_OFFSTACK=y
From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
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 <ard.biesheuvel@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1488395154-29786-1-git-send-email-ard.biesheuvel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
Patches currently in stable-queue which might be from ard.biesheuvel@xxxxxxxxxx are
queue-4.9/efi-arm-fix-boot-crash-with-config_cpumask_offstack-y.patch