Using PGDIR_SHIFT to identify espfix64 addresses on 5-level systems was wrong, and it resulted in panics due to unhandled double faults. Use P4D_SHIFT instead, which is correct on 4-level and 5-level machines.

This fixes a panic when running x86 selftests on 5-level machines.

Fixes: 1d33b219563f ("x86/espfix: Add support for 5-level paging") Cc: stable@vger.kernel.org Cc: "Kirill A. Shutemov" kirill@shutemov.name Cc: Dave Hansen dave.hansen@intel.com Signed-off-by: Andy Lutomirski luto@kernel.org --- arch/x86/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 74136fd16f49..c4e5b0a7516f 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -360,7 +360,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) * * No need for ist_enter here because we don't use RCU. */ - if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY && + if (((long)regs->sp >> P4D_SHIFT) == ESPFIX_PGD_ENTRY && regs->cs == __KERNEL_CS && regs->ip == (unsigned long)native_irq_return_iret) {