Re: Kernel panic with PREEMPT_RT_FULL and UIO driver

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

On Wed, Dec 21, 2011 at 11:48:36AM +0100, Lukas Erlinghagen wrote:
> Dear list,
> 
> we're getting the kernel panic postet below on our system (Kernel
> version is 3.0.3-rt11, the platform is an embedded PowerPC 440 in a
Are you aware that there are newer versions available? 3.0.14-rt31 is
the most recent 3.0 release. Don't know if it has any uio fixes though.

> Virtex 5 FPGA, the device controlled by the UIO driver is a
> Freescale MFR4310 controller, and the interrupt is triggered by a
> high-active interrupt pin). This panic only occurs when using
> CONFIG_PREEMPT_RT_FULL, and only under high interrupt load on the
> MFR.
> 
> I've also included our IRQ handler (registered with IRQF_ONESHOT)
> and IRQ control function.
> 
> Is there something fundamentally wrong we're doing, and if so, where
> can I find information on The Right Way to write UIO drivers for the
> RT kernel?
> 
> Thanks in advance for any insight you can provide.
> 
> Kernel panic:
> 
> ------------[ cut here ]------------
> kernel BUG at kernel/rtmutex.c:724!
That's a recursive spinlock. Try enabling CONFIG_PROVE_LOCKING.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html