From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Stanislav Meduna <stano@meduna.org>,
"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
Linux ARM Kernel <linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25
Date: Wed, 23 Apr 2014 09:14:33 +0200 [thread overview]
Message-ID: <53576859.8060706@linutronix.de> (raw)
In-Reply-To: <20140422141650.7f43d5ba@gandalf.local.home>
On 04/22/2014 08:16 PM, Steven Rostedt wrote:
> --- a/kernel/timer.c
> +++ b/kernel/timer.c
> @@ -1447,6 +1447,12 @@ static void run_timer_softirq(struct softirq_action *h)
> __run_timers(base);
> }
>
> +#ifdef CONFIG_SMP
> +#define timer_should_raise_softirq(lock) !spin_do_trylock(lock)
> +#else
> +#define timer_should_raise_softirq(lock) 1
> +#endif
> +
No. The lock may be taken but it also may be available no matter if UP
or not. With this patch applied the lockdep splat will go away but the
FULL_NO_HZ people will come back because the timer softirq is scheduled
even if no timer has expired.
Sebastian
WARNING: multiple messages have this Message-ID (diff)
From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25
Date: Wed, 23 Apr 2014 09:14:33 +0200 [thread overview]
Message-ID: <53576859.8060706@linutronix.de> (raw)
In-Reply-To: <20140422141650.7f43d5ba@gandalf.local.home>
On 04/22/2014 08:16 PM, Steven Rostedt wrote:
> --- a/kernel/timer.c
> +++ b/kernel/timer.c
> @@ -1447,6 +1447,12 @@ static void run_timer_softirq(struct softirq_action *h)
> __run_timers(base);
> }
>
> +#ifdef CONFIG_SMP
> +#define timer_should_raise_softirq(lock) !spin_do_trylock(lock)
> +#else
> +#define timer_should_raise_softirq(lock) 1
> +#endif
> +
No. The lock may be taken but it also may be available no matter if UP
or not. With this patch applied the lockdep splat will go away but the
FULL_NO_HZ people will come back because the timer softirq is scheduled
even if no timer has expired.
Sebastian
next prev parent reply other threads:[~2014-04-23 7:14 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-14 19:24 BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 Stanislav Meduna
2014-04-14 23:45 ` Stanislav Meduna
2014-04-14 23:45 ` Stanislav Meduna
2014-04-15 22:08 ` Stanislav Meduna
2014-04-15 22:08 ` Stanislav Meduna
2014-04-17 16:29 ` BUG: spinlock trylock failure on UP - reverting timer patches helps Stanislav Meduna
2014-04-17 16:29 ` Stanislav Meduna
2014-04-17 22:55 ` Stanislav Meduna
2014-04-17 22:55 ` Stanislav Meduna
2014-04-17 23:10 ` jordan
2014-04-17 23:10 ` jordan
2014-04-18 1:15 ` jordan
2014-04-18 1:15 ` jordan
2014-04-18 1:15 ` jordan
2014-04-18 14:45 ` Stanislav Meduna
2014-04-18 14:45 ` Stanislav Meduna
2014-04-18 15:09 ` jordan
2014-04-18 15:09 ` jordan
2014-04-22 11:54 ` BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 Sebastian Andrzej Siewior
2014-04-22 11:54 ` Sebastian Andrzej Siewior
2014-04-22 13:46 ` Steven Rostedt
2014-04-22 13:46 ` Steven Rostedt
2014-04-22 14:09 ` Peter Zijlstra
2014-04-22 14:09 ` Peter Zijlstra
2014-04-23 8:10 ` Sebastian Andrzej Siewior
2014-04-23 8:10 ` Sebastian Andrzej Siewior
2014-04-23 8:50 ` Peter Zijlstra
2014-04-23 8:50 ` Peter Zijlstra
2014-04-22 16:51 ` Sebastian Andrzej Siewior
2014-04-22 16:51 ` Sebastian Andrzej Siewior
2014-04-22 17:48 ` Steven Rostedt
2014-04-22 17:48 ` Steven Rostedt
2014-04-22 18:16 ` Steven Rostedt
2014-04-22 18:16 ` Steven Rostedt
2014-04-23 7:14 ` Sebastian Andrzej Siewior [this message]
2014-04-23 7:14 ` Sebastian Andrzej Siewior
2014-04-23 8:49 ` Peter Zijlstra
2014-04-23 8:49 ` Peter Zijlstra
2014-04-23 12:15 ` Steven Rostedt
2014-04-23 12:15 ` Steven Rostedt
2014-05-02 18:38 ` Sebastian Andrzej Siewior
2014-05-02 18:38 ` Sebastian Andrzej Siewior
2014-05-02 19:01 ` Thomas Gleixner
2014-05-02 19:01 ` Thomas Gleixner
2014-05-02 19:36 ` Thomas Gleixner
2014-05-02 19:36 ` Thomas Gleixner
2014-05-02 19:37 ` Sebastian Andrzej Siewior
2014-05-02 19:37 ` Sebastian Andrzej Siewior
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