Commit-ID: d1eb98143c56f24fef125f5bbed49ae0b52fb7d6 Gitweb: http://git.kernel.org/tip/d1eb98143c56f24fef125f5bbed49ae0b52fb7d6 Author: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> AuthorDate: Wed, 1 Mar 2017 19:05:54 +0000 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 2 Mar 2017 08:11:19 +0100 efi/arm: Fix boot crash with CONFIG_CPUMASK_OFFSTACK=y 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: <stable@xxxxxxxxxxxxxxx> # v4.5+ 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> --- drivers/firmware/efi/arm-runtime.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c index 349dc3e..974c5a3 100644 --- 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; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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