dtrace pid provider on entry == Trace/BPT trap process

[Mark Johnston]

On Tue, Sep 05, 2017 at 12:58:22PM +0200, Andreas Longwitz wrote:
> I use FreeBSD 10.3-STABLE r317936 with updated /usr/lib/dtrace/ip.c and
> see an issue that in my opinion should have been solved in r269342:

10.3 would be missing a number of other fixes for issues that might
cause the symptom you're seeing. Unfortunately, userland DTrace is not
very usable on FreeBSD before 11.0.

> I run a simple program looptest, that loops around a sprintf() call and
> want to check this program with
> 
> dtrace -n 'pid$target:libc.so.*::entry {@[probefunc] = count();}' -p
> $(pgrep looptest)
> dtrace: description 'pid$target:libc.so.*::entry ' matched 3863 probes
> 
> After some seconds I hit CTRL-C and see
> 
>   __vfprintf                                                   741685
>   localeconv_l                                                 741685
>   memset                                                       741685
>   sprintf                                                      741685
>   vsprintf                                                     741685
>   __sfvwrite                                                  1483369
>   memcpy                                                      2225052
> 
> and at the same time looptest stops with
>    Trace/BPT trap (Speicherabzug geschrieben)
> and on the console I see the kernel message
>    pid 67550 (looptest), uid 1003: exited on signal 5 (core dumped)
> 
> The trap does not occur all the time, but it is no problem to repeat the
> trap.