[Xenomai] Some Information About compilation Xenomai and RT Patches

Stoidner, Christoph c.stoidner at arvero.de
Mon Jun 23 11:33:15 CEST 2014

Hi Gilles,

when a userspace application starts it calls the brk() syscall to enlarge it's heap space. In some cases the call leads to an NOMEM error in fcse_check_mmap_addr(). Since glibc does not handle NOMEM error at this place the a segfault exception appears.

It seems as this happens when brk() got an address above some limit, also when the process at all consumes less than 32MB RAM. E.g. busybox shell command "ls" is enough to get the segfault.


Von: Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org>
Gesendet: Freitag, 20. Juni 2014 13:50
An: Stoidner, Christoph; xenomai at xenomai.org
Betreff: Re: [Xenomai] Some Information About compilation Xenomai and RT Patches

On 06/20/2014 11:02 AM, Stoidner, Christoph wrote:
> My pending problem which I hope to solve soon is the fast context
> switch extension (FCSE) that allows better latency times on ARM9. In
> "guaranteed" mode it crashs when using addresses above 32MB.

What do you mean it crashes? Normally, an mmap call that would return
addresses above 32MB simply fails, because you can not use addresses
above 32MB in guaranteed mode.


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