Re: misc oprofile-tests updates

On Fri, 2016-04-01 at 17:21 +0200, Michael Petlan wrote:
> On Wed, 30 Mar 2016, Will Schmidt wrote:
> > Hi Oprofile devs,
> >
> > A handful of changes to the oprofile-tests suite, for consideration.
> >
> > I stumbled across an issue while running the tests, dug in a bit, and came
> > out with this short series of patches to improve things.  Most of the
> > changes are cosmetic, but a couple will affect the suite behavior, most
> > notably that more of the tests will be runnable as a normal user, and we
> > will successfully run more tests as root when the kptr_restrict mode is
> > in restricted mode, where we previously would have punted.  (Additional
> > detail in the patch descriptions.)
> >
> > I've tested these changes against an older (0.9.8) install, as well as
> > against latest (1.2.0git), no new issues in my testing.
> >
> > As a user:
> > before:  49/49 tests passed.
> > after:   74/78 to 78/78 tests passed.  (depending on the value of kptr_restrict)
> >
> > As root:
> > No notable changes.  My latest run showed
> > after:  113/117 to 117/117 tests passed.  (depending on kptr_restrict)
> >
> > Thanks,
> > -Will
> >
> 
> Hi,
> 
> I have run the testsuite with your patches on a few machines and I like
> the changes. Thank you for them.
> 
> I am interested in the failures related to the value of kptr_restrict.
> Could you please provide more information about your testing?
>
> Which kptr_restrict values it passes with? Which values it fails with?
> Which kernel versions, archs, systems have you used?

I'm mostly power focused, so ppc64 and ppc64le arches on power7 and
power8 hardware.    I do some sniff tests on x86.  The distro flavor
varies, mostly fedora based, but some RHEL/SuSE/Ubuntu installs
sprinkled in from time to time. 

For the kernel versions, at a glance the oldest I've run against is
2.6.32.*, and newest is 4.2.0.*.  All distro provided kernels.

> I have met an issue with incorrect kallsyms detection (see the patch
> I have sent recently). I noticed that issue by running the patched suite
> where it was reporting "set kptr_restrict to 0" despite having it 0.

Is that the blurb that now looks like so: ? 
        fail  "    Failed to obtain the kernel symbols from kallsyms."
        print "Verify the test is being run as root or that "
        print "/proc/sys/kernel/kptr_restrict is set to 0."
        send "The current value of kptr_restrict is: "

The alternative path into that error message would be if something else
went wrong such that the expected symbol was not found in the
opreport.  


> Also please try to run
> 
> grep -e ' _stext' -e ' _text' -e ' _etext' /proc/kallsyms

Each of my boxes returns roughly the following.  
power:
c000000000000000 T _stext
c000000000000000 T _text
c000000000950000 R _etext
x86:
ffffffff81000000 T _text
ffffffff810001c8 T _stext
ffffffff8177a6f2 T _etext

when kptr_restrict is 2, the values are always zero'd out, regardless of
if I run that grep as root or user.
when kptr_restrict is 1, the values are zero for user, valid for root.
and when kptr_restrict is 0, values are always valid.

> on the box(es) where you tested the suite and send the output. In case
> your kernel's kallsyms file has the _stext symbol, could you also try
> to run the tests against oprofile with my patch if anything changes.

I don't see any obvious changes in output with your patch applied.  The
_stext and _text values on the power systems appear to always be the
same, at the bottom of the kernel address space, so would not make a
difference there.  On the x86* boxes I've got, that value varies just a
little bit,.. I'm not sure how significant that delta is in the grand
scheme of things, I don't expect a whole lot of symbols are in the
*[000]-*[1c8] range that I'd be missing. :-)


What arch/kernel versions are you seeing the problem with?  I'll look
closer/deeper if I can.  

Thanks,
-Will


> 
> Thank you!
> 
> Michael
> 
> >
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> 



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