Re: [PATCH] perf test: Fix probe testsuite with a new error message

[Veronika Molnarova <vmolnaro@redhat.com>]

On 10/10/24 16:40, Arnaldo Carvalho de Melo wrote:
> On Thu, Oct 10, 2024, 10:31 AM Veronika Molnarova <vmolnaro@redhat.com>
> wrote:
> 
>>
>>
>> On 10/10/24 14:50, Arnaldo Carvalho de Melo wrote:
>>> On Thu, Oct 10, 2024 at 09:48:52AM -0300, Arnaldo Carvalho de Melo wrote:
>>>> On Wed, Oct 09, 2024 at 10:16:20PM -0700, Namhyung Kim wrote:
>>>>> On my system, it's constantly failing because of new error message from
>>>>> perf probe.  It should update the regex pattern to match the message -
>>>>> "A function DIE doesn't have decl_line. Maybe broken DWARF?".
>>>>>
>>>>>   $ sudo head -n 2 /sys/kernel/debug/kprobes/blacklist | cut -f2
>>>>>   warn_thunk_thunk
>>>>>   asm_exc_divide_error
>>>>>
>>>>>   $ sudo perf probe warn_thunk_thunk
>>>>>   A function DIE doesn't have decl_line. Maybe broken DWARF?
>>>>>   A function DIE doesn't have decl_line. Maybe broken DWARF?
>>>>>   Probe point 'warn_thunk_thunk' not found.
>>>>>     Error: Failed to add events.
>>>>>
>>>>>   $ sudo perf probe asm_exc_overflow
>>>>>   Failed to find scope of probe point.
>>>>>     Error: Failed to add events.
>>>>
>>>> We discussed this in the past, I came up with a similar patch, Veronika
>>>> rightly pointed out that this may point to a real problem, Masami said
>>>> that since these are for DWARF from assembly those are known issues, I
>>>> suggested Veronika checked if the CU where the function came from was
>>>> generated from Assembly (there are DWARF tags that have that info), IIRC
>>>> she said she would try to do it.
>>>>
>>>> I'll try to find out the threads and see what happened.
>>>
>>> https://lore.kernel.org/all/ZvXhJLkJcR99Y2sF@google.com/T/#u
>>>
>>> Veronika, was there a v3?
>>>
>>> Thanks,
>> Well the patch was already applied upstream so we are talking about a fix
>> not v3, right?
> 
> 
> 
> 
> Can you provide a url for the patch that was applied upstream?
> 
> I just checked at
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/log/tools/perf/tests/shell/base_probe/test_adding_blacklisted.sh?h=perf-tools-next
> 
> And I'm not seeing it.

Well the patch adding the failing test case that you can see at

https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/log/tools/perf/tests/shell/base_probe/test_adding_blacklisted.sh?h=perf-tools-next

There was the whole patchset that contained the failing probe test case.
The patchset was applied and merged upstream so there won't be a v3 for 
the failing test case, instead we will send a fix patch resolving the 
mentioned issue. Hopefully this explains the confusion that I think
happened.

We will send the next patchset soon containing also the patch fixing
the probe issue with bad dwarf so if there will still be some confusion 
that should resolve that.

- Veronika

> 
> - Arnaldo
> 
> As Arnaldo mentioned, I got together a fix patch that checks
> 
>> the CU for the Assembly for blacklisted probe. Michael also suggested the
>> possibility to check multiple blacklisted probes if we are not able to
>> check
>> for the Assembly, so I also added that.
>>
>> I will send the fix patch soon as part of the perftool upstreaming patchset
>> to prevent conflicts happening. Hopefully, this can be at the start of the
>> next week if all of the checks pass.
>>
>> Thanks,
>> Veronika
>>>
>>> - Arnaldo
>>>
>>
>>
>