From: Steven Rostedt <rostedt@goodmis.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
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: Tue, 22 Apr 2014 14:16:50 -0400 [thread overview]
Message-ID: <20140422141650.7f43d5ba@gandalf.local.home> (raw)
In-Reply-To: <20140422134802.73fc1fa4@gandalf.local.home>
On Tue, 22 Apr 2014 13:48:02 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> I need to take a deeper look into the actual code. But as trylocks on
> UP are nops (always succeed), and if it expects to be able to do
> something in a critical section that is protected by spinlocks (again
> nops on UP), this would be broken for UP.
Reading the code, I see it's broken. We should add something like this:
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
diff --git a/kernel/timer.c b/kernel/timer.c
index cc34e42..a03164a 100644
--- 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
+
/*
* Called by the local, per-CPU timer interrupt on SMP.
*/
@@ -1467,7 +1473,7 @@ void run_local_timers(void)
return;
}
- if (!spin_do_trylock(&base->lock)) {
+ if (timer_should_raise_softirq(&base->lock)) {
raise_softirq(TIMER_SOFTIRQ);
return;
}
next prev parent reply other threads:[~2014-04-22 18:16 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 ` BUG: spinlock trylock failure on UP, i.MX28 3.12.15-rt25 Sebastian Andrzej Siewior
2014-04-22 13:46 ` 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 [this message]
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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