linux-kernel - Re: [PATCH v1 0/2] perf report: Support annotation of code without symbols

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Date:   Thu, 20 Feb 2020 21:50:42 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v1 0/2] perf report: Support annotation of code without
 symbols



On 2/20/2020 8:06 PM, Jiri Olsa wrote:
> On Thu, Feb 20, 2020 at 08:03:18PM +0800, Jin, Yao wrote:
>>
>>
>> On 2/20/2020 7:56 PM, Jiri Olsa wrote:
>>> On Thu, Feb 20, 2020 at 08:59:00AM +0800, Jin Yao wrote:
>>>> For perf report on stripped binaries it is currently impossible to do
>>>> annotation. The annotation state is all tied to symbols, but there are
>>>> either no symbols, or symbols are not covering all the code.
>>>>
>>>> We should support the annotation functionality even without symbols.
>>>>
>>>> The first patch uses al_addr to print because it's easy to dump
>>>> the instructions from this address in binary for branch mode.
>>>>
>>>> The second patch supports the annotation on stripped binary.
>>>>
>>>> Jin Yao (2):
>>>>     perf util: Print al_addr when symbol is not found
>>>>     perf annotate: Support interactive annotation of code without symbols
>>>
>>> looks good, but I'm getting crash when annotating unresolved kernel address:
>>>
>>> jirka
>>>
>>>
>>
>> Thanks for reporting the issue.
>>
>> I guess you are trying the "0xffffffff81c00ae7", let me try to reproduce
>> this issue.
> 
> yes, I also checked and it did not happen before
> 
> jirka
> 


I can reproduce it now.

perf record -e cycles:u ls
perf report --stdio

     75.29%  ls       ld-2.27.so        [.] do_lookup_x
     23.64%  ls       ld-2.27.so        [.] __GI___tunables_init
      1.04%  ls       [unknown]         [k] 0xffffffff85c01210
      0.03%  ls       ld-2.27.so        [.] _start

Looks it's caused by skid.

Thanks
Jin Yao