[Xenomai-help] Problem trying to find secondary mode switches.

[Xenomai-help] Problem trying to find secondary mode switches.

[Gilles Chanteperdrix]

Hi,

I am using the XNTRAPSW option to try and find secondary mode switches
in some piece of code for which I do not have the sources. I have
installed the usual signal handler which dumps the backtrace, just as in
ksrc/skins/native/snippet/sigxcpu.c. But the problem is that the
backtrace is not helpful, it show addresses in libpthread and
libpthread_rt global destructor sections.

By adding some printks in shadow.c I know that what causes the mode
switch is the linux arm syscall 78 aka gettimeofday.

So, my question is: is there any chance that the signal sent by send_sig
in xnshadow_relax could be received by another thread than send_sig
target ? If not, where should I look for the reason of this wrong
backtrace ?


-- 
                                                 Gilles Chanteperdrix

Re: [Xenomai-help] Problem trying to find secondary mode switches.

[Dmitry Adamushko]

Hi,

> [...]
> So, my question is: is there any chance that the signal sent by send_sig
> in xnshadow_relax could be received by another thread than send_sig
> target ?

Nop, as far as I can see. Anyway, you can easily verify it by printing
current->pid for the send_sig()'s target in xnshadow_relax() and
calling gettid() (not getpid()) in your signal handler.

> If not, where should I look for the reason of this wrong
> backtrace ?

Are you sure backtrace() is always workable on ARM? I just know that
it's not a case for MIPS..


>
> --
>                                                  Gilles Chanteperdrix

-- 
Best regards,
Dmitry Adamushko