Freeze using Linux function tracer on Xenomai 2.6

Jan Kiszka jan.kiszka at
Wed Aug 21 19:03:16 CEST 2019

On 21.08.19 17:43, Radu Rendec via Xenomai wrote:
> Hi Everyone,
> I know Xenomai 2.6 has been obsolete for a long time now, but I'm stuck
> with a legacy environment that I have to support.
> Having said that, I enabled the Linux function tracer in the kernel
> configuration and I experience a complete system freeze when I try to
> activate it. Basically I'm doing this:
>    mount debugfs /sys/kernel/debug/ -t debugfs
>    echo function > /sys/kernel/debug/tracing/current_tracer
> At that point I get a freeze. The system eventually reboots, but after
> 10 minutes or so - even though no hardware watchdog is enabled.
> I'm running Xenomai 2.6.5 on Linux 3.2.102, on a PowerPC e300 (Freescale
> MPC8378). Only Busybox init, sshd and a Busybox shell are running at the
> time this happens.
> Can anyone think of any reason why this might happen or how I can figure
> out what goes wrong?

I never hacked on ppc, but I would bet that ftrace & Co. was never hardened 
there for use under Xenomai. Then, it may work for some time by luck and later 
crash randomly.

Maybe the ipipe tracer worked there.


Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

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