From 12dd19c159659ec9050f45dc8a2ff3c3917f4be3 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Sat, 13 Aug 2022 19:45:21 +0200 Subject: [PATCH] s390/boot: fix absolute zero lowcore corruption on boot Crash dump always starts on CPU0. In case CPU0 is offline the prefix page is not installed and the absolute zero lowcore is used. However, struct lowcore::mcesad is never assigned and stays zero. That leads to __machine_kdump() -> save_vx_regs() call silently stores vector registers to the absolute lowcore at 0x11b0 offset. Fixes: a62bc0739253 ("s390/kdump: add support for vector extension") Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik --- arch/s390/kernel/nmi.c | 2 +- arch/s390/kernel/setup.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c index 60ac66aab163..31cb9b00a36b 100644 --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -64,7 +64,7 @@ static inline unsigned long nmi_get_mcesa_size(void) * structure. The structure is required for machine check happening * early in the boot process. */ -static struct mcesa boot_mcesa __initdata __aligned(MCESA_MAX_SIZE); +static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE); void __init nmi_alloc_mcesa_early(u64 *mcesad) { diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index ed4fbbbdd1b0..74adb433c257 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -479,6 +479,7 @@ static void __init setup_lowcore_dat_off(void) put_abs_lowcore(restart_data, lc->restart_data); put_abs_lowcore(restart_source, lc->restart_source); put_abs_lowcore(restart_psw, lc->restart_psw); + put_abs_lowcore(mcesad, lc->mcesad); mcck_stack = (unsigned long)memblock_alloc(THREAD_SIZE, THREAD_SIZE); if (!mcck_stack)