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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Tom Cook <tom.k.cook@gmail.com>,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: Tracers+cyclictest causing kernel oops
Date: Tue, 21 May 2013 13:16:55 +0200	[thread overview]
Message-ID: <519B57A7.1010901@linutronix.de> (raw)
In-Reply-To: <CAFSh4UwD5yyJrtKwUaOX-uiUuzVf7YaDbM4vbZ1EFZBf6F1JHg@mail.gmail.com>

please CC the list.

On 05/11/2013 06:43 PM, Tom Cook wrote:
> Okay, I've built the same kernel config but without kgdb enabled.
> Running cyclictest with a tracer enabled (-f in this case) causes the
> crash below.
> 
> I'm not big on debugging these things yet.  Since cyclictest works
> without the tracers enabled and causes a crash with them enabled, the
> problem must be in the tracers themselves, right?  Actually, 'echo
> function > current_tracer' has the same effect.
> 
> Is that trace really saying that the processor is in mode 0?  AFAICT,
> ARM does not have a mode 0 unless you truncate the mode number to four
> bits - in which case mode '0' is user mode.  The process name seems to
> be a red herring - repeating this can turn up almost any process
> running on the system, from interrupt handler threads to bash.
> 
> Is this a known problem?  Any tips on figuring it out?

Not known until you brought that up. I just booted x86 with kgdb=y and
did "echo function > current_tracer" with no side effects. I don't have
ARM at hand right now. Do you do anything kgdb related besides enabling
it in the kernel?

> 
> Thanks,
> Tom

Sebastian

  parent reply	other threads:[~2013-05-21 11:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-26  8:04 Tracers+cyclictest causing kernel oops Tom Cook
2013-04-29  7:16 ` Tom Cook
2013-05-03 16:05   ` Sebastian Andrzej Siewior
2013-05-12  5:14     ` Tom Cook
     [not found]     ` <CAFSh4UwD5yyJrtKwUaOX-uiUuzVf7YaDbM4vbZ1EFZBf6F1JHg@mail.gmail.com>
2013-05-21 11:16       ` Sebastian Andrzej Siewior [this message]
2013-05-21 15:20         ` Tom Cook
2013-05-27  8:02           ` Uwe Kleine-König
2013-05-27 21:23             ` Tom Cook
2013-05-28  6:53               ` Uwe Kleine-König
2013-06-21 11:01                 ` Tom Cook
2013-05-31  9:23           ` Sebastian Andrzej Siewior
2013-05-31  9:31             ` Tom Cook
2013-06-21 11:21             ` Tom Cook
2013-06-21 14:17               ` Tom Cook
2013-06-21 14:58                 ` Tom Cook
2013-06-21 15:00               ` Sebastian Andrzej Siewior

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