Re: [PATCH] perf report: Fix segfault with '-F phys_daddr'

[Ravi Bangoria <ravi.bangoria@linux.ibm.com>]

On 11/12/19 7:48 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Nov 12, 2019 at 07:28:06PM +0530, Ravi Bangoria escreveu:
>>
>>
>> On 11/12/19 4:34 PM, Arnaldo Carvalho de Melo wrote:
>>> Em Tue, Nov 12, 2019 at 11:19:46AM +0530, Ravi Bangoria escreveu:
>>>> If perf.data file is not recorded with mem-info, adding 'phys_daddr'
>>>> to output field in perf report results in segfault. Fix that.
>>>>
>>>> Before:
>>>>     $ ./perf record ls
>>>>     $ ./perf report -F +phys_daddr
>>>>     Segmentation fault (core dumped)
>>>>
>>>> After:
>>>>     $ ./perf report -F +phys_daddr
>>>>     Samples: 11  of event 'cycles:u', Event count (approx.): 1485821
>>>>     Overhead  Data Physical Address  Command  Shared Object  Symbol
>>>>       22.57%  [.] 0000000000000000   ls       libc-2.29.so   [.] __strcoll_l
>>>>       21.87%  [.] 0000000000000000   ls       ld-2.29.so     [.] _dl_relocate_object
>>>>       ...
>>>
>>> Shouldn't we instead just bail out and state that this isn't possible
>>> and leave the user wondering why what was asked isn't presented?
>>
>> You mean popup with something like "phys_daddr is not available in perf.data"
>> and also don't show that column in perf report?
> 
> Just bail out completely, something like:
> 
> 
>     $ ./perf report -F +phys_daddr
>     "phys_daddr" is not available in perf.data, use 'record -e some,thing' to have it.

Sure. Thanks for the suggestion. Will re-spin.

Ravi