Re: [PATCH rt] Fix latency histogram after "hrtimer: Set expiry time before switch_hrtimer_base()"

From: Steven Rostedt
Date: Mon Jun 30 2014 - 12:10:54 EST


On Sat, 28 Jun 2014 23:34:48 +0100
Ben Hutchings <ben@xxxxxxxxxxxxxxx> wrote:

> In an rt-kernel with CONFIG_MISSED_TIMER_OFFSETS_HIST enabled,
> __hrtimer_start_range_ns() now crashes, as new_base is not assigned
> before it is used.
>
> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> Tested-by: Carsten Emde <C.Emde@xxxxxxxxx>
> Cc: stable-rt@xxxxxxxxxxxxxxx

Thanks, I'm applying it now. Will need to go through the various tests
before I push it out.

-- Steve

> ---
> --- a/kernel/hrtimer.c
> +++ b/kernel/hrtimer.c
> @@ -1106,6 +1106,11 @@ int __hrtimer_start_range_ns(struct hrti
> #endif
> }
>
> + hrtimer_set_expires_range_ns(timer, tim, delta_ns);
> +
> + /* Switch the timer base, if necessary: */
> + new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
> +
> #ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
> {
> ktime_t now = new_base->get_time();
> @@ -1117,11 +1122,6 @@ int __hrtimer_start_range_ns(struct hrti
> }
> #endif
>
> - hrtimer_set_expires_range_ns(timer, tim, delta_ns);
> -
> - /* Switch the timer base, if necessary: */
> - new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
> -
> timer_stats_hrtimer_set_start_info(timer);
>
> leftmost = enqueue_hrtimer(timer, new_base);
>

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