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From: Thomas Gleixner <tglx@linutronix.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	John Stultz <john.stultz@linaro.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>
Subject: Re: [patch 38/44] posix-cpu-timers: Respect INFINITY for hard RTTIME limit
Date: Mon, 19 Aug 2019 22:29:13 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.1908192225350.4008@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190819200650.GE68079@gmail.com>

On Mon, 19 Aug 2019, Ingo Molnar wrote:
> * Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> > The RTIME limit expiry code does not check the hard RTTIME limit for
> > INFINITY, i.e. being disabled.  Add it.
> > 
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > ---
> >  kernel/time/posix-cpu-timers.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > --- a/kernel/time/posix-cpu-timers.c
> > +++ b/kernel/time/posix-cpu-timers.c
> > @@ -905,7 +905,7 @@ static void check_process_timers(struct
> >  		u64 softns, ptime = samples[CPUCLOCK_PROF];
> >  		unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
> >  
> > -		if (psecs >= hard) {
> > +		if (hard != RLIM_INFINITY && psecs >= hard) {
> >  			/*
> >  			 * At the hard limit, we just die.
> >  			 * No need to calculate anything else now.
> 
> Might make sense to mark this as a possible ABI change in the changelog: 
> if some weird code learned to rely on this (arguably broken) behavior 
> then the bug turned into an ABI.

Will do, though that would be really interesting to see the offending
case. That limit is in seconds and RLIM_INFINITY is at least INT_MAX which
means 68 years. :)

I stumbled over it when I tried to consolidate that duplicated code in that
area. I'll amend the changelog to be more clear.

Thanks,

	tglx

  reply	other threads:[~2019-08-19 20:29 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-19 14:31 [patch 00/44] posix-cpu-timers: Cleanup and consolidation Thomas Gleixner
2019-08-19 14:31 ` [patch 01/44] posix-timers: Cleanup forward declarations and includes Thomas Gleixner
2019-08-20 12:20   ` Frederic Weisbecker
2019-08-20 13:03     ` Thomas Gleixner
2019-08-20 13:48   ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 02/44] alarmtimers: Avoid rtc.h include Thomas Gleixner
2019-08-20 13:49   ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 03/44] posix-timer: Use a callback for cancel synchronization Thomas Gleixner
2019-08-20  2:21   ` Christoph Hellwig
2019-08-20 13:08     ` Thomas Gleixner
2019-08-20 13:59   ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] posix-timers: Use a callback for cancel synchronization on PREEMPT_RT tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 04/44] posix-cpu-timers: Fixup stale comment Thomas Gleixner
2019-08-20 14:26   ` Frederic Weisbecker
2019-08-20 17:57     ` Thomas Gleixner
2019-08-20 20:48       ` Frederic Weisbecker
2019-08-20 21:43         ` Thomas Gleixner
2019-08-20 22:56           ` Frederic Weisbecker
2019-08-21 13:31             ` Thomas Gleixner
2019-08-21 15:51               ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 05/44] posix-cpu-timers: Sanitize bogus WARNONS Thomas Gleixner
2019-08-21 11:34   ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 06/44] posix-cpu-timers: Remove tsk argument from run_posix_cpu_timers() Thomas Gleixner
2019-08-21 11:36   ` Frederic Weisbecker
2019-08-23  2:12   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-19 14:31 ` [patch 07/44] posix-cpu-timers: Simplify sighand locking in run_posix_cpu_timers() Thomas Gleixner
2019-08-21 12:09   ` Frederic Weisbecker
2019-08-21 13:25     ` Thomas Gleixner
2019-08-21 15:42       ` Frederic Weisbecker
2019-08-21 17:13         ` Thomas Gleixner
2019-08-19 14:31 ` [patch 08/44] posix-cpu-timers: Provide task validation functions Thomas Gleixner
2019-08-19 14:31 ` [patch 09/44] posix-cpu-timers: Use common permission check in posix_cpu_clock_get() Thomas Gleixner
2019-08-19 14:31 ` [patch 10/44] posix-cpu-timers: Use common permission check in posix_cpu_timer_create() Thomas Gleixner
2019-08-19 14:31 ` [patch 11/44] posix-cpu-timers: Provide quick sample function for itimer Thomas Gleixner
2019-08-19 14:31 ` [patch 12/44] itimers: Use quick sample function Thomas Gleixner
2019-08-19 14:31 ` [patch 13/44] posix-cpu-timers: Sample directly in timer check Thomas Gleixner
2019-08-19 14:31 ` [patch 14/44] posix-cpu-timers: Rename thread_group_cputimer() and make it static Thomas Gleixner
2019-08-19 14:31 ` [patch 15/44] posix-cpu-timer: Comsolidate thread group sample code Thomas Gleixner
2019-08-19 19:07   ` Ingo Molnar
2019-08-19 14:31 ` [patch 16/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_set() Thomas Gleixner
2019-08-19 14:31 ` [patch 17/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_get() Thomas Gleixner
2019-08-19 14:31 ` [patch 18/44] posix-cpu-timers: Use clock ID in posix_cpu_timer_rearm() Thomas Gleixner
2019-08-19 14:32 ` [patch 19/44] posix-cpu-timer: Remove pointless return value check Thomas Gleixner
2019-08-19 14:32 ` [patch 20/44] posix-cpu-timers: Simplify sample functions Thomas Gleixner
2019-08-19 14:32 ` [patch 21/44] posix-cpu-timers: Get rid of pointer indirection Thomas Gleixner
2019-08-19 14:32 ` [patch 22/44] posix-cpu-timers: Sample task times once in expiry check Thomas Gleixner
2019-08-19 14:32 ` [patch 23/44] posix-cpu-timers: Move prof/virt_ticks into caller Thomas Gleixner
2019-08-19 14:32 ` [patch 24/44] posix-cpu-timers: Create a container struct Thomas Gleixner
2019-08-19 14:32 ` [patch 25/44] sched: Move struct task_cputime to types.h Thomas Gleixner
2019-08-19 14:32 ` [patch 26/44] posix-cpu-timers: Move expiry cache into struct posix_cputimers Thomas Gleixner
2019-08-19 14:32 ` [patch 27/44] posix-cpu-timers: Provide array based access to expiry cache Thomas Gleixner
2019-08-19 19:32   ` Ingo Molnar
2019-08-20 20:22     ` Thomas Gleixner
2019-08-19 14:32 ` [patch 28/44] posix-cpu-timers: Simplify timer queueing Thomas Gleixner
2019-08-19 14:32 ` [patch 29/44] posix-cpu-timers: Simplify set_process_cpu_timer() Thomas Gleixner
2019-08-19 14:32 ` [patch 30/44] posix-cpu-timers: Switch check_*_timers() to array cache Thomas Gleixner
2019-08-19 14:32 ` [patch 31/44] posix-cpu-timers: Remove the odd field rename defines Thomas Gleixner
2019-08-19 14:32 ` [patch 32/44] posix-cpu-timers: Provide array based sample functions Thomas Gleixner
2019-08-19 14:32 ` [patch 33/44] posix-cpu-timers: Make expiry checks array based Thomas Gleixner
2019-08-19 14:32 ` [patch 34/44] posix-cpu-timers: Remove cputime_expires Thomas Gleixner
2019-08-19 14:32 ` [patch 35/44] posix-cpu-timers: Switch thread group sampling to array Thomas Gleixner
2019-08-19 14:32 ` [patch 36/44] posix-cpu-timers: Get rid of zero checks Thomas Gleixner
2019-08-19 14:32 ` [patch 37/44] posix-cpu-timers: Consolidate timer expiry further Thomas Gleixner
2019-08-19 14:32 ` [patch 38/44] posix-cpu-timers: Respect INFINITY for hard RTTIME limit Thomas Gleixner
2019-08-19 20:06   ` Ingo Molnar
2019-08-19 20:29     ` Thomas Gleixner [this message]
2019-08-19 14:32 ` [patch 39/44] posix-cpu-timers: Get rid of 64bit divisions Thomas Gleixner
2019-08-19 14:32 ` [patch 40/44] posix-cpu-timers: Remove pointless comparisions Thomas Gleixner
2019-08-19 20:10   ` Ingo Molnar
2019-08-19 14:32 ` [patch 41/44] posix-cpu-timers: Deduplicate rlimit handling Thomas Gleixner
2019-08-19 14:32 ` [patch 42/44] posix-cpu-timers: Move state tracking to struct posix_cputimers Thomas Gleixner
2019-08-19 19:13   ` Ingo Molnar
2019-08-19 20:29     ` Thomas Gleixner
2019-08-19 14:32 ` [patch 43/44] posix-cpu-timers: Utilize timerqueue for storage Thomas Gleixner
2019-08-19 14:32 ` [patch 44/44] posix-cpu-timers: Expire timers directly Thomas Gleixner
2019-08-19 19:09   ` Ingo Molnar
2019-08-20 13:07   ` Thomas Gleixner
2019-08-20  2:18 ` [patch 00/44] posix-cpu-timers: Cleanup and consolidation Christoph Hellwig
2019-08-20 13:09   ` Thomas Gleixner

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