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From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	john stultz <johnstul@us.ibm.com>
Subject: Re: [RT] Race condition on bug output.
Date: Wed, 7 Dec 2005 09:33:55 +0100	[thread overview]
Message-ID: <20051207083355.GA22190@elte.hu> (raw)
In-Reply-To: <1133926493.6724.109.camel@localhost.localdomain>


* Steven Rostedt <rostedt@goodmis.org> wrote:

> Hi Ingo,
> 
> I found a race condition in my kernel which can also be found in 
> yours. When I trigger the printk in check_periodic_interval, 
> interrupts are turned on in release_console_sem.  Unfortunately, this 
> can have an interrupt go off there (since they are turned back on 
> there) and the write_lock system_time_lock will be taken again, thus 
> producing a deadlock.
> 
> I'm not sure if this is the best solution, but this was the easiest.
> 
> Maybe the CONFIG_PARANOID_GENERIC_TIME should be added in the warnings 
> in init/main.c too?
> 
> Since interrupts are kept off in the ktimer (hrtimer, whatever) in 
> printk, this does not affect those patches.  This is a PREEMPT_RT only 
> problem.

thanks, applied.

	Ingo

      reply	other threads:[~2005-12-07  8:33 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-07  3:34 Steven Rostedt
2005-12-07  8:33 ` Ingo Molnar [this message]

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