From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Stanislav Meduna <stano@meduna.org>
Cc: "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>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25
Date: Tue, 22 Apr 2014 13:54:39 +0200 [thread overview]
Message-ID: <20140422115439.GA20669@linutronix.de> (raw)
In-Reply-To: <534DADF1.6060608@meduna.org>
* Stanislav Meduna | 2014-04-16 00:08:49 [+0200]:
>Hmm... how is it in the rt-case guaranteed that the timer interrupt
>does not preempt someone trying to modify the timer? The run_local_timers
>looks to have arrived via hardirq context. The spinlock in the tvec_base
>is a normal one and spin_lock_irqsave does not disable interrupts
>on rt, right?
this is, erm, harmless. We grab the timer lock via trylock in hardirq
context. If the lock is already taken then we fail to get it we go for
plan B. According to lockdep a trylock should not fail on UP. This is
true in general except for this timer case. I was thinking abour
disabling this lockdep check…
Sebastian
next prev parent reply other threads:[~2014-04-22 11:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <534C3606.7010206@meduna.org>
2014-04-14 23:45 ` BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 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 22:55 ` Stanislav Meduna
2014-04-17 23:10 ` jordan
2014-04-18 1:15 ` jordan
2014-04-18 14:45 ` Stanislav Meduna
2014-04-18 15:09 ` jordan
2014-04-22 11:54 ` Sebastian Andrzej Siewior [this message]
2014-04-22 13:46 ` BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 Steven Rostedt
2014-04-22 14:09 ` Peter Zijlstra
2014-04-23 8:10 ` Sebastian Andrzej Siewior
2014-04-23 8:50 ` Peter Zijlstra
2014-04-22 16:51 ` Sebastian Andrzej Siewior
2014-04-22 17:48 ` Steven Rostedt
2014-04-22 18:16 ` Steven Rostedt
2014-04-23 7:14 ` Sebastian Andrzej Siewior
2014-04-23 8:49 ` Peter Zijlstra
2014-04-23 12:15 ` Steven Rostedt
2014-05-02 18:38 ` Sebastian Andrzej Siewior
2014-05-02 19:01 ` Thomas Gleixner
2014-05-02 19:36 ` Thomas Gleixner
2014-05-02 19:37 ` Sebastian Andrzej Siewior
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