On 12.08.2021 22:31, Thomas Gleixner wrote: > clock_was_set() can be invoked from preemptible context. Use raw_cpu_ptr() > to check whether high resolution mode is active or not. It does not matter > whether the task migrates after acquiring the pointer. > > Fixes: e71a4153b7c2 ("hrtimer: Force clock_was_set() handling for the HIGHRES=n, NOHZ=y case") > Reported-by: Mike Galbraith <efault@xxxxxx> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> This fixes the following issue: BUG: using smp_processor_id() in preemptible [00000000] code: hwclock/227 > --- > kernel/time/hrtimer.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > --- a/kernel/time/hrtimer.c > +++ b/kernel/time/hrtimer.c > @@ -944,10 +944,11 @@ static bool update_needs_ipi(struct hrti > */ > void clock_was_set(unsigned int bases) > { > + struct hrtimer_cpu_base *cpu_base = raw_cpu_ptr(&hrtimer_bases); > cpumask_var_t mask; > int cpu; > > - if (!hrtimer_hres_active() && !tick_nohz_active) > + if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active) > goto out_timerfd; > > if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) { > @@ -958,9 +959,9 @@ void clock_was_set(unsigned int bases) > /* Avoid interrupting CPUs if possible */ > cpus_read_lock(); > for_each_online_cpu(cpu) { > - struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu); > unsigned long flags; > > + cpu_base = &per_cpu(hrtimer_bases, cpu); > raw_spin_lock_irqsave(&cpu_base->lock, flags); > > if (update_needs_ipi(cpu_base, bases)) > Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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