Re: [PATCH] time: Remove CONFIG_TIMER_STATS

2017-02-08 Thread John Stultz
On Wed, Feb 8, 2017 at 2:24 AM, Thomas Gleixner  wrote:
> On Tue, 7 Feb 2017, John Stultz wrote:
>> On Tue, Feb 7, 2017 at 3:40 PM, Kees Cook  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: <>, 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 
>> > Signed-off-by: Kees Cook 
>>
>> 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 
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Re: [PATCH] time: Remove CONFIG_TIMER_STATS

2017-02-08 Thread Thomas Gleixner
On Tue, 7 Feb 2017, John Stultz wrote:
> On Tue, Feb 7, 2017 at 3:40 PM, Kees Cook  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: <>, 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 
> > Signed-off-by: Kees Cook 
> 
> 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.

Thanks,

tglx
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Re: [PATCH] time: Remove CONFIG_TIMER_STATS

2017-02-07 Thread kbuild test robot
Hi Kees,

[auto build test WARNING on tip/timers/core]
[also build test WARNING on v4.10-rc7 next-20170207]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Kees-Cook/time-Remove-CONFIG_TIMER_STATS/20170208-080916
reproduce: make htmldocs

All warnings (new ones prefixed by >>):

   make[3]: warning: jobserver unavailable: using -j1.  Add '+' to parent make 
rule.
   include/linux/init.h:1: warning: no structured comments found
>> include/linux/hrtimer.h:108: warning: Excess struct/union/enum/typedef 
>> member 'start_pid' description in 'hrtimer'
>> include/linux/hrtimer.h:108: warning: Excess struct/union/enum/typedef 
>> member 'start_site' description in 'hrtimer'
>> include/linux/hrtimer.h:108: warning: Excess struct/union/enum/typedef 
>> member 'start_comm' description in 'hrtimer'
   include/linux/kthread.h:26: warning: Excess function parameter '...' 
description in 'kthread_create'
   kernel/sys.c:1: warning: no structured comments found
   drivers/dma-buf/seqno-fence.c:1: warning: no structured comments found
   include/drm/drm_drv.h:409: warning: No description found for parameter 'load'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'firstopen'
   include/drm/drm_drv.h:409: warning: No description found for parameter 'open'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'preclose'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'postclose'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'lastclose'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'unload'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'dma_ioctl'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'dma_quiescent'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'context_dtor'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'set_busid'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'irq_handler'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'irq_preinstall'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'irq_postinstall'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'irq_uninstall'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'debugfs_init'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'debugfs_cleanup'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_open_object'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_close_object'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'prime_handle_to_fd'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'prime_fd_to_handle'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_export'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_import'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_pin'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_unpin'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_res_obj'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_get_sg_table'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_import_sg_table'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_vmap'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_vunmap'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_prime_mmap'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'vgaarb_irq'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'gem_vm_ops'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'major'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'minor'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'patchlevel'
   include/drm/drm_drv.h:409: warning: No description found for parameter 'name'
   include/drm/drm_drv.h:409: warning: No description found for parameter 'desc'
   include/drm/drm_drv.h:409: warning: No description found for parameter 'date'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'driver_features'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'dev_priv_size'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'ioctls'
   include/drm/drm_drv.h:409: warning: No description found for parameter 
'num_ioctls'
   includ

Re: [PATCH] time: Remove CONFIG_TIMER_STATS

2017-02-07 Thread John Stultz
On Tue, Feb 7, 2017 at 3:40 PM, Kees Cook  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: <>, 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 
> Signed-off-by: Kees Cook 

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?

thanks
-john
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