Re: BPF relocation 'perf test' entries failing was: Re: [GIT PULL 00/27] perf/core improvements and fixes

From: Thomas-Mich Richter
Date: Fri Jul 27 2018 - 02:27:41 EST


On 07/26/2018 09:14 PM, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jul 26, 2018 at 03:58:05PM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Thu, Jul 26, 2018 at 11:04:08PM +0530, Sandipan Das escreveu:
>>> I came across the same problem. Does the following patch fix it?
>
>>> https://lkml.org/lkml/2018/7/26/669
>
>> Oh my, that one was subtle... Checking...
>
> Right, when it said it was running:
>
> 40.3: BPF prologue generation
>
> In fact it was running:
>
> 40.4: BPF relocation checker
>
> That error message in the 'perf test -v' output:
>
> libbpf: Program 'func=sys_write' contains non-map related relo data pointing to section 65522
>
> Was the _expected_ one for "40.4: BPF relocation checker", then it
> failed when it couldn't run the off by one "last" subtest, duh.
>
> Thomas, this was a problem introduced by a patch from you, just for
> reference, this one:
>
> Fixes: 9ef0112442bd ("perf test: Fix subtest number when showing results")
>
> I should have caught this by running 'perf test' before/after applying
> that patch, I'll now make sure this is done before sending pull reqs
> upstream.
>
> In fact I did after, and thought, hey, some BPF related regression, I
> must've updated clang/llvm and something new appeared on the radar, so I
> went that direction and went nowhere, well, now I have an uptodate
> llvm/clang combo to play with BTF, pahole, etc 8-)
>
> Thanks!
>
> - Arnaldo



Sandipan,
thanks for fixing what I have messed up.

Arnaldo,
sorry for the hickup, I should have caught this too. In fact I ran
perf test before and after, but redirected the output and just
looked at the grep'ed lines on the screen....
I should be looked more carefully...

Apologies for the mess and thanks again for fixing this.

--
Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
--
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