Messages in this thread Patch in this message | | | Date | Mon, 16 Oct 2017 11:30:47 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: PROBLEM: Kernel BUG in mfgpt_tick (cs5535-clockevt.c) on ALIX 2c3 - null call |
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On Thu, 12 Oct 2017, David Kozub wrote: > On Thu, 12 Oct 2017, Thomas Gleixner wrote: > > On Thu, 12 Oct 2017, Daniel Lezcano wrote: > > The real question is why > > > > /* Set the clock scale and enable the event mode for CMP2 */ > > val = MFGPT_SCALE | (3 << 8); > > > > cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP, val); > > > > is in the setup code at all. > > > > The obvious place for this is in mfgpt_set_periodic() which gets called > > when the clock event and the handler is set up in the core code. Up to that > > point the interrupt handler is protected against shared interrupts via the > > is_shutdown() check. > > It is, but only after clockevents_config_and_register. But mfgpt_tick is > called before that (just after setup_irq).
Right, but the protection against the spurious interrupt there is not sufficient. See patch below.
Thanks,
tglx
8<-------------------
--- a/drivers/clocksource/cs5535-clockevt.c +++ b/drivers/clocksource/cs5535-clockevt.c @@ -117,7 +117,8 @@ static irqreturn_t mfgpt_tick(int irq, void *dev_id) /* Turn off the clock (and clear the event) */ disable_timer(cs5535_event_clock); - if (clockevent_state_shutdown(&cs5535_clockevent)) + if (clockevent_state_detached(&cs5535_clockevent) || + clockevent_state_shutdown(&cs5535_clockevent)) return IRQ_HANDLED; /* Clear the counter */
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