From 0986d97741150b307775d56f587a73ea873a4f4d Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 9 Feb 2016 16:23:39 +0100 Subject: [PATCH] s390: fix DAT off memory access, e.g. on kdump commit 204ee2c56431 ("s390/irqflags: optimize irq restore") optimized irqrestore to really only care about interrupts and adapted the remaining low level users. One spot (memcpy_real) was not touched, though - fix it. Otherwise a kdump kernel will fail while reading the old kernel. As we re-enable irqs with a non-standard function we have to tell lockdep about that. Fixes: 204ee2c56431 ("s390/irqflags: optimize irq restore") Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/mm/maccess.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index fec59c067d0d..350b0acd7f52 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -101,7 +101,9 @@ int memcpy_real(void *dest, void *src, size_t count) local_irq_save(flags); __arch_local_irq_stnsm(0xfbUL); rc = __memcpy_real(dest, src, count); - local_irq_restore(flags); + if (!arch_irqs_disabled_flags(flags)) + trace_hardirqs_on(); + __arch_local_irq_ssm(flags); return rc; }