Userland dtrace broken?

[Chris Nehren]

On Wed, Aug 29, 2012 at 14:01:15 +0100 , Matt Burke wrote:
> Following http://wiki.freebsd.org/DTrace/userland on 9.1-RC1, the example
> fails to work as demonstrated:
> 
> # dtrace -s pid.d -c test
> dtrace: script 'pid.d' matched 2 probes
> CPU     ID                    FUNCTION:NAME
>   1  59284                       main:entry
> dtrace: pid 25479 exited with status 1
> 
> #
> 
> 
> Also, I get hangs when trying to do pretty much anything with the pid:::entry
> 
> # dtrace -n 'pid$target::malloc:entry' -c 'echo x'
> dtrace: description 'pid$target::malloc:entry' matched 2 probes
> xCPU     ID                    FUNCTION:NAME
>   1  59311                     malloc:entry
> load: 0.43  cmd: dtrace 63737 [running] 8.93r 1.60u 4.19s 35% 25072k
> load: 0.88  cmd: echo 63738 [running] 45.10r 2.27u 18.75s 47% 1452k
> load: 1.19  cmd: dtrace 63737 [running] 70.32r 12.14u 33.27s 64% 25072k
> 
> # procstat -k 63737 63738
>   PID    TID COMM             TDNAME           KSTACK
> 63737 101505 dtrace           -                mi_switch
> sleepq_catch_signals sleepq_timedwait_sig _sleep do_wait
> __umtx_op_wait_uint_private amd64_syscall Xfast_syscall
> 63737 111024 dtrace           -                <running>
> 63738 101657 echo             -                mi_switch
> thread_suspend_switch ptracestop cursig ast doreti_ast
> 
> 
> I have previously tried using dtrace on 9.0R, but it was insta-panic. Is
> there anything I may have missed here?
> 
> 
> 
> make.conf:
> STRIP=
> CFLAGS+=-fno-omit-frame-pointer
> WITH_CTF=1
> 
> kernel config:
> include         GENERIC
> ident           DTRACE
> 
> makeoptions     DEBUG="-g"
> makeoptions     WITH_CTF=1
> options         KDTRACE_FRAME
> options         KDTRACE_HOOKS
> options         DDB_CTF
> options         DDB
> 

Relevant to my interests, too. I've followed the instructions on the
wiki / in the handbook (on 9.0/9.1-PRE) and only receive error messages.
Is DTrace supposed to be working properly on 9.x, or is it still
experimental?

It's nice to say that FreeBSD nominally supports DTrace, but if it
doesn't actually work then it needs to be labelled as such. I am fine
with it being experimental if that's the case, but saying so would help
manage expectations a lot better.

-- 
Thanks and best regards,
Chris Nehren
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