Re: [PATCH] time: Remove CONFIG_TIMER_STATS

From	John Stultz <john.stultz@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] time: Remove CONFIG_TIMER_STATS
Date	2017-02-08 19:10 +0100
Message-ID	<t8EQO-3Ed-9@gated-at.bofh.it> (permalink)
References	<t8nGi-ZA-19@gated-at.bofh.it> <t8s3g-3Oc-5@gated-at.bofh.it> <t8xFD-7xu-3@gated-at.bofh.it>
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On Wed, Feb 8, 2017 at 2:24 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Tue, 7 Feb 2017, John Stultz wrote:
>> On Tue, Feb 7, 2017 at 3:40 PM, Kees Cook <keescook@chromium.org> wrote:
>> > Currently CONFIG_TIMER_STATS exposes process information across namespaces:
>> >
>> > kernel/time/timer_list.c print_timer():
>> >
>> >         SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
>> >
>> > /proc/timer_list:
>> >
>> >  #11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570
>> >
>> > Given that the tracer can give the same information, this patch entirely
>> > removes CONFIG_TIMER_STATS.
>> >
>> > Suggested-by: Thomas Gleixner <tglx@linutronix.de>
>> > Signed-off-by: Kees Cook <keescook@chromium.org>
>>
>> I don't have an issue with this, but I worry this would break some
>> tooling out there. Should it be marked as deprecated first?
>>
>> Or maybe just pulling the band-aid off is the best way?
>
> I think we should just kill it.
>
> No tools can really rely on the behaviour of that file because it depends
> on CONFIG_TIMER_STATS and the information available there is just a random
> snapshot of queued timers at a given point of time, which is in no way
> usefull.

Fair enough.

Acked-by: John Stultz <john.stultz@linaro.org>

Thread

[PATCH] time: Remove CONFIG_TIMER_STATS Kees Cook <keescook@chromium.org> - 2017-02-08 00:50 +0100
  Re: [PATCH] time: Remove CONFIG_TIMER_STATS John Stultz <john.stultz@linaro.org> - 2017-02-08 05:30 +0100
    Re: [PATCH] time: Remove CONFIG_TIMER_STATS Thomas Gleixner <tglx@linutronix.de> - 2017-02-08 11:30 +0100
      Re: [PATCH] time: Remove CONFIG_TIMER_STATS John Stultz <john.stultz@linaro.org> - 2017-02-08 19:10 +0100
  Re: [PATCH] time: Remove CONFIG_TIMER_STATS kbuild test robot <lkp@intel.com> - 2017-02-08 05:50 +0100

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