Re: Backward compatibility for insn probe point

[Maynard Johnson <maynardj@us.ibm.com>]

David Smith wrote:
> Maynard Johnson wrote:
>> Frank has already made the changes in runtime/itrace.c to support
>> backward compatibility with older utrace.
>> I wanted to test the insn probe point on an older utrace, so I built
>> and installed systemtap 0.9.5 on a ppc970 blade running RHEL 5.3.  I
>> ran the following simple test:
>>
>> # stap -c /bin/ls simple-test.stp /bin/ls -o simple-out -k -vvv 
>>      where simple-test.stp is . . .
>> =========simple-test.stp ========================
>> global instrs = 0
>>
>> probe begin {
>> 	printf("systemtap starting probe\n")
>> }
>>
>> probe process(@1).insn {
>> 	instrs += 1
>> }
>>
>> probe end { printf("systemtap ending probe\n")
>> printf("itraced = %d\n", instrs)
>> }
>> ==================================
>>
>> The result of the above test is that the stap command hangs at
>> "stapio:start_cmd:195 execing target_cmd /bin/ls".  If I Ctl-C the
>> job, it finished (i.e, I see "Pass 5: run completed ..."), but the
>> output file contents indicate the insn probe was not hit (i.e.,
>> "itraced = 0").
>>
>> Any suggestions on where to look for the problem?
> 
> I took a look at this and fixed it.  For more details, see
Excellent!  Thanks much.  I hadn't gotten very far debugging this -- too many other irons in the fire, I'm afraid.  I will test it out on ppc64 RHEL 5 and Fedora 11 and let you know my results.

-Maynard 
> <http://sources.redhat.com/bugzilla/show_bug.cgi?id=10091>.
>