Hello Sebastian, Am Dienstag, 27. August 2019, 15:22:01 CEST schrieb Sebastian Andrzej Siewior: > of course, !SMP. What about this: > > diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c > --- a/kernel/time/hrtimer.c > +++ b/kernel/time/hrtimer.c > @@ -934,7 +934,11 @@ void hrtimer_grab_expiry_lock(const struct hrtimer > *timer) { > struct hrtimer_clock_base *base = READ_ONCE(timer->base); > > +#ifdef CONFIG_SMP > if (timer->is_soft && base != &migration_base) { > +#else > + if (timer->is_soft && base && base->cpu_base) { > +#endif > spin_lock(&base->cpu_base->softirq_expiry_lock); > spin_unlock(&base->cpu_base->softirq_expiry_lock); > } Build error is gone and target system boots successfully, seems to work fine at first sight. Thanks for the quick response. Greets Alex