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From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
	peter@hurleysoftware.com, rjw@rjwysocki.net,
	torvalds@linux-foundation.org, tglx@linutronix.de,
	eparis@redhat.com, umgwanakikbuti@gmail.com, marcel@holtmann.org,
	ebiederm@xmission.com, davem@davemloft.net,
	fengguang.wu@intel.com
Subject: Re: [PATCH 7/7] sched: Use WARN_ONCE for the might_sleep() TASK_RUNNING test
Date: Fri, 31 Oct 2014 23:42:37 +0100	[thread overview]
Message-ID: <20141031224237.GA29704@redhat.com> (raw)
In-Reply-To: <20141031111549.857381983@infradead.org>

On 10/31, Peter Zijlstra wrote:
>
> In some cases this can trigger a true flood of output.
>
> Requested-by: Ingo Molnar <mingo@kernel.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>  kernel/sched/core.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -7301,7 +7301,7 @@ void __might_sleep(const char *file, int
>  	 * since we will exit with TASK_RUNNING make sure we enter with it,
>  	 * otherwise we will destroy state.
>  	 */
> -	if (WARN(current->state != TASK_RUNNING,
> +	if (WARN_ONCE(current->state != TASK_RUNNING,

Agreed, but sorry for off-topic, can't resist.

Sometimes I hate WARN_ONCE() because you can't reproduce the problem
once again without reboot.

Perhaps WARN_ON_RATELIMIT() should be used more often (not sure about
this particular case). Or, perhaps, we can add a special section for
these "__warned" variables and add, say, sysctl which clears that
section ?

Oleg.


  reply	other threads:[~2014-10-31 22:43 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-31 11:10 [PATCH 0/7] Various fixes for nested sleep stuff Peter Zijlstra
2014-10-31 11:10 ` [PATCH 1/7] sched,wait: Fix a kthread race with wait_woken() Peter Zijlstra
2014-10-31 22:13   ` Oleg Nesterov
2014-10-31 11:10 ` [PATCH 2/7] wait: Reimplement wait_event_freezable() Peter Zijlstra
2014-10-31 17:41   ` Peter Zijlstra
2014-10-31 21:38   ` Oleg Nesterov
2014-10-31 21:48     ` Peter Zijlstra
2014-10-31 21:53     ` Oleg Nesterov
2014-10-31 11:10 ` [PATCH 3/7] wait: Remove wait_event_freezekillable() Peter Zijlstra
2014-10-31 11:10 ` [PATCH 4/7] audit,wait: Fixup kauditd_thread wait loop Peter Zijlstra
2014-10-31 11:10 ` [PATCH 5/7] rfcomm: Fix broken wait construct Peter Zijlstra
2014-10-31 11:10 ` [PATCH 6/7] netdev: Fix sleeping inside wait event Peter Zijlstra
2014-10-31 11:10 ` [PATCH 7/7] sched: Use WARN_ONCE for the might_sleep() TASK_RUNNING test Peter Zijlstra
2014-10-31 22:42   ` Oleg Nesterov [this message]
2014-11-03  7:56     ` Peter Zijlstra

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