Messages in this thread | | | Date | Thu, 26 Oct 2017 14:57:41 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: Query regarding __hrtimer_get_next_event() |
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On Thu, 26 Oct 2017, Neeraj Upadhyay wrote: > We have one query regarding the __hrtimer_get_next_event(). > The expires_next.tv64 is set to 0 if it is < 0. We observed > an hrtimer interrupt storm for one of the hrtimers with > below properties: > > * Expires for the hrtimer was set to KTIME_MAX. > * cpu base was HRTIMER_BASE_REALTIME with negative base->offset. > * Due to below sub, expires overflowed to a negative value and > expires_next.tv64 was set to 0 > expires = ktime_sub(hrtimer_get_expires(timer), base->offset); > * Due to this, clockevent was programmed to min_delta_ns, everytime > as __hrtimer_get_next_event() returned 0. > > > This may not be a valid use case (queuing a hrtimer with KTIME_MAX) > expires, but should we guard the hrtimer next event code against > this by using KTIME_MAX upper bound. Is something like below a > proper way to guard it? Or am I missing something here?
Can you please explain how you managed to have a negative base->offset?
Thanks,
tglx
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