4.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Omar Sandoval <[email protected]> commit 6f6266a561306e206e0e31a5038f029b6a7b1d89 upstream. Reserving a runtime region results in splitting the EFI memory descriptors for the runtime region. This results in runtime region descriptors with bogus memory mappings, leading to interesting crashes like the following during a kexec: general protection fault: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1 #53 Hardware name: Wiwynn Leopard-Orv2/Leopard-DDR BW, BIOS LBM05 09/30/2016 RIP: 0010:virt_efi_set_variable() ... Call Trace: efi_delete_dummy_variable() efi_enter_virtual_mode() start_kernel() ? set_init_arg() x86_64_start_reservations() x86_64_start_kernel() start_cpu() ... Kernel panic - not syncing: Fatal exception Runtime regions will not be freed and do not need to be reserved, so skip the memmap modification in this case. Signed-off-by: Omar Sandoval <[email protected]> Signed-off-by: Matt Fleming <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Dave Young <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Jones <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/platform/efi/quirks.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_ad return; } + /* No need to reserve regions that will never be freed. */ + if (md.attribute & EFI_MEMORY_RUNTIME) + return; + size += addr % EFI_PAGE_SIZE; size = round_up(size, EFI_PAGE_SIZE); addr = round_down(addr, EFI_PAGE_SIZE);
