stap early exit

[Jim Keniston <jkenisto at us dot ibm dot com>]

A SystemTap user at IBM is seeing his stap script terminate after a few
minutes, for no reason that he or I can figure out.  The final message
is:
stapio:cleanup_and_exit:229 closing control channel

Conversation below; script attached.

Any suggestions?

Thanks.
Jim

dvhltc@us.ibm.c... out of curiosity, what makes a "stap mytapset.stp"
stop collecting data?
dvhltc@us.ibm.... is there some internal buffer maximum?
kenistoj@us.ibm... Are you missing some data?
dvhltc@us.ibm.... well I run the command and it spits out data for a
while, then it stops and tells me how long it ran... but there is
nothing in my stp file that indicates loops or time limits
dvhltc@us.ibm.... just a couple probe definitions
kenistoj@us.ibm... No call to exit()?
dvhltc@us.ibm.... nope
kenistoj@us.ibm... Are you using stap -c?
dvhltc@us.ibm.... [provided pointer to mutex.stp]
dvhltc@us.ibm.... no I just ran stap
dvhltc@us.ibm.... "stap mutex.stp"
dvhltc@us.ibm.... then kicked off my load in another terminal
kenistoj@us.ibm... No, I don't understand why.
kenistoj@us.ibm... Weird.
kenistoj@us.ibm... Did you do CTRL-C or send stap a SIGINT or whatever?
dvhltc@us.ibm.... nope, nothing overtly stupid like that :-)
dvhltc@us.ibm.... more subtle ignorance here I think
kenistoj@us.ibm... How long did it run?
kenistoj@us.ibm... Minutes?
dvhltc@us.ibm.... ended with:
dvhltc@us.ibm.... stapio:cleanup_and_exit:229 closing control channel
Pass 5: run completed in 50usr/120sys/213446real ms.
Running rm -rf /tmp/stapKMvt3d

dvhltc@us.ibm.... so yeah, nearly 4 monutes
...
kenistoj@us.ibm... Is "stapio:cleanup_and_exit:229 closing control
channel" nearly or exactly what you saw, or an approximation?
dvhltc@us.ibm.... exactly
dvhltc@us.ibm.... copy/paste

(See attached file: mutex.stp)

Attachment: mutex.stp
Description: Binary data