Re: [PATCH] perf report: Fix a bug on "--call-graph none" option

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Sep 30, 2015 at 01:34:00PM +0900, Namhyung Kim escreveu:
> The patch f9db0d0f1b2c ("perf callchain: Allow disabling call graphs
> per event") added an ability to enable/disable callchain recording per
> event.  But it had a problem when the enablement setting is changed at
> 'perf report' time using -g/--call-graph option.
> 
> For example, the following scenario will get a segfault.
> 
>   $ perf record -ag sleep 1
>   [ perf record: Woken up 1 times to write data ]
>   [ perf record: Captured and wrote 0.500 MB perf.data (2555 samples) ]
> 
>   $ perf report -g none
>   perf: Segmentation fault
>   -------- backtrace --------
>   perf[0x53a98a]
>   /usr/lib/libc.so.6(+0x335af)[0x7f4e91df95af]
> 
> This is because callchain_param.sort() callback was not set but it
> tried to call the function as it had the PERF_SAMPLE_CALLCHAIN bit.

Thanks, reproduced, tested the fix, applied.

- Arnaldo