Updating from 0303 to 0505 has problems

[Quentin Barnes]

On Tue, May 08, 2007 at 03:14:49PM -0500, Quentin Barnes wrote:
>I wanted to start pushing some of my systemtap runtime changes back
>to the mailing list, so I just updated Systemtap on my ARM system
>from 20070303 to 20070505 to verify my work.
>
>With 0505 I'm getting dozens of new "eof" failures such as:
>
>	FAIL: systemtap.base/add.stp shutdown (eof)

I upgraded from 2.6.20.4 to 2.6.21.1 and still have the problem, so I
continued researching it.

It seems to be an intermittent problem.  I can run the same test
several times in a row.  Sometimes it will pass just fine where
other times I'll get the (eof) failure.

Here's a run that works:
================
Pass 5: starting run.
systemtap starting probe
PASS: systemtap.base/be_order.stp startup
PASS: systemtap.base/be_order.stp load generation
systemtap ending probe
systemtap test success
systemtap test success
PASS: systemtap.base/be_order.stp shutdown and output
Pass 5: run completed in 400usr/1280sys/2862real ms.
metric: systemtap.base/be_order.stp     8240    8680    16931   180     70      250     0       0       0       0       0       0       400     1280    2862
testcase /usr/src/systemtap-20070505/testsuite/systemtap.base/be_order.exp completed in 22 seconds
================

Here's the same test, but from a run when it fails:
================
Pass 5: starting run.
systemtap starting probe
PASS: systemtap.base/be_order.stp startup
PASS: systemtap.base/be_order.stp load generation
poll warning: Interrupted system call
systemtap ending probe
systemtap test success
systemtap test success
Pass 5: run completed in 440usr/1520sys/3159real ms.^M
FAIL: systemtap.base/be_order.stp shutdown (eof)
testcase /usr/src/systemtap-20070505/testsuite/systemtap.base/be_order.exp completed in 22 seconds
================

Looking at stap_run.exp, it's looking for "systemtap ending probe\n
systemtap test success".  When I run stap directly on the .stp file,
it always outputs the right string.  Is this some sort of race condition
where sometimes "expect" is seeing the end-of-file condition on the file
descriptor before expect has a chance to match the pattern?  Any ideas
to try out?

Quentin