From ce4dda3f02aca959bdd18b596513791d77b8b7e1 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 2 Dec 2016 13:29:22 +0100 Subject: [PATCH] s390: fix machine check panic stack switch For system damage machine checks or machine checks due to invalid PSW fields the system will be stopped. In order to get an oops message out before killing the system the machine check handler branches to .Lmcck_panic, switches to the panic stack and then does the usual machine check handling. The switch to the panic stack is incomplete, the stack pointer in %r15 is replaced, but the pt_regs pointer in %r11 is not. The result is a program check which will kill the system in a slightly different way. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 161f4e66f67d..1a450d220f56 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -958,7 +958,7 @@ ENTRY(mcck_int_handler) .Lmcck_panic: lg %r15,__LC_PANIC_STACK - aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) + la %r11,STACK_FRAME_OVERHEAD(%r15) j .Lmcck_skip # -- 2.20.1