On Fri, 25 Aug 2017 12:31:17 +0200
Thomas Gleixner <[email protected]> wrote:
> -__visible void __irq_entry smp_trace_reschedule_interrupt(struct pt_regs
> *regs)
> -{
> - /*
> - * Need to call irq_enter() before calling the trace point.
> - * __smp_reschedule_interrupt() calls irq_enter/exit() too (in
> - * scheduler_ipi(). This is OK, since those functions are allowed
> - * to nest.
> - */
> - ipi_entering_ack_irq();
> - trace_reschedule_entry(RESCHEDULE_VECTOR);
> + if (trace_irqvectors_enabled()) {
> + /*
> + * scheduler_ipi() might call irq_enter() as well, but
> + * nested calls are fine.
> + */
> + irq_enter();
> + trace_reschedule_entry(RESCHEDULE_VECTOR);
> + }
> +
> inc_irq_stat(irq_resched_count);
> scheduler_ipi();
> - trace_reschedule_exit(RESCHEDULE_VECTOR);
> - exiting_irq();
> +
> + if (trace_irqvectors_enabled()) {
> + trace_reschedule_exit(RESCHEDULE_VECTOR);
> + irq_exit();
This is racy. If the static key gets changed on one and not the other,
we lose the irq_enter/irq_exit match.
-- Steve
> + }
> }
>
> __visible void __irq_entry smp_call_function_interrupt(struct pt_regs *regs)
>
