stap --rlimit-stack=1 does not behave as expected in RHEL6.4

stap --rlimit-stack=1 does not behave as expected in RHEL6.4

[Hien Nguyen]

Under RHEL6.4 and systemtap-1.8x, I run the rlimit.exp testcase, it 
failed this test

FAIL: rlimit STACK small


Upon looking under the hood, it looks like the test doing this and 
expecting stap to crash or fail.

exec stap --rlimit-stack=1 -p4 systemtap.base/rlimit.stp

However, stap did not crash and successfully built the stap-xxx.ko.

I saw a bug filed on this, but there is no follow up

http://sourceware.org/bugzilla/show_bug.cgi?id=13977

I wonder if anyone run into this same issue.

Thanks, Hien.

Re: stap --rlimit-stack=1 does not behave as expected in RHEL6.4

[David Smith]

On 06/19/2013 05:55 PM, Hien Nguyen wrote:
> Under RHEL6.4 and systemtap-1.8x, I run the rlimit.exp testcase, it
> failed this test
> 
> FAIL: rlimit STACK small
> 
> 
> Upon looking under the hood, it looks like the test doing this and
> expecting stap to crash or fail.
> 
> exec stap --rlimit-stack=1 -p4 systemtap.base/rlimit.stp
> 
> However, stap did not crash and successfully built the stap-xxx.ko.
> 
> I saw a bug filed on this, but there is no follow up
> 
> http://sourceware.org/bugzilla/show_bug.cgi?id=13977
> 
> I wonder if anyone run into this same issue.
> 
> Thanks, Hien.

After looking at this one for awhile, I decided to just remove the
"STACK small" test. I verified that the stap executable is calling
setrlimit() correctly, and the new stack limit is getting set correctly
on the process. However, the RHEL6 kernel ignores that limit (perhaps
because the stack is already larger than that?). Since there is no point
in fighting the kernel here, I just removed that test.

-- 
David Smith
dsmith@redhat.com
Red Hat
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