Le Vendredi, Août 21, 2020 20:04 CEST, Jan Kiszka <[email protected]> a 
écrit:

> On 20.08.20 15:46, François Legal via Xenomai wrote:
> > Using RTNet with multiple interfaces, xenomai 3.1 with linux 4.4
> > Whenever a posix RT thread calls recvmsg (), I get this error.
> >
> > I could track this down to line 422 in udp.c :     msg = rtnet_get_arg(fd, 
> > &_msg, u_msg, sizeof(_msg));
> >
> > If I disassemble the kernel, the failing instruction (at 0x80272444) is a 
> > nop in arm_copy_from_user
> > Am I doing anything wrong ?
>
> Maybe you are passing an invalid pointer to recvmsg, directly or in its
> message structures. That would cause an exception which is fixed up but
> also reported. Do you get an error in return?
>

So, I checked, and the same happens on calls to sendto ().
I doubt the pointer passed is invalid, as I don't get that kind of problems 
with 3.0.9.
Upon return from recvmsg or sendto, I get -1 with errno set to 14.
Also, I checked in ipipe_base.h, exception #0 seem to be an instruction/data 
access exception, which seems very weird to me for a NOP instruction that does 
not appear to be on a line/page boundary.

François

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


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