Re: [PATCH 05/12] perf tools: Read also the end of the kernel

[Jiri Olsa]

On Fri, May 24, 2019 at 03:46:07PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, May 24, 2019 at 03:17:17PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, May 24, 2019 at 03:15:06PM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Wed, May 08, 2019 at 03:20:03PM +0200, Jiri Olsa escreveu:
> > > > We mark the end of kernel based on the first module,
> > > > but that could cover some bpf program maps. Reading
> > > > _etext symbol if it's present to get precise kernel
> > > > map end.
> > > 
> > > Investigating... Have you run 'perf test' before hitting the send
> > > button? :-)
> > 
> > <SNIP>
> > 
> > > [root@quaco c]# perf test -v 1
> > >  1: vmlinux symtab matches kallsyms                       :
> > <SNIP>
> > > --- start ---
> > > ERR : 0xffffffff8cc00e41: __indirect_thunk_end not on kallsyms
> > <SNIP>
> > > test child finished with -1
> > > ---- end ----
> > > vmlinux symtab matches kallsyms: FAILED!
> > > [root@quaco c]#
> > 
> > So...
> > 
> > [root@quaco c]# grep __indirect_thunk_end /proc/kallsyms
> > ffffffff8cc00e41 T __indirect_thunk_end
> > [root@quaco c]# grep -w _etext /proc/kallsyms
> > ffffffff8cc00e41 T _etext
> > [root@quaco c]#
> > 
> > [root@quaco c]# grep -w ffffffff8cc00e41 /proc/kallsyms
> > ffffffff8cc00e41 T _etext
> > ffffffff8cc00e41 T __indirect_thunk_end
> > [root@quaco c]#
> > 
> > Lemme try to fix this.
> 
> So, I got this right before your patch:
> 
> commit 1d1c54c5bbf55256e691bedb47b0d14745043e80
> Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Date:   Fri May 24 15:39:00 2019 -0300
> 
>     perf test vmlinux-kallsyms: Ignore aliases to _etext when searching on kallsyms
>     
>     No need to search for aliases for the symbol that marks the end of the
>     kernel text segment, the following patch will make such symbols not to
>     be found when searching in the kallsyms maps causing this test to fail.
>     
>     So as a prep patch to avoid breaking bisection, ignore such symbols.
>     
>     Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>     Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
>     Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>     Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
>     Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
>     Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>     Cc: Song Liu <songliubraving@xxxxxx>
>     Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
>     Cc: Thomas Richter <tmricht@xxxxxxxxxxxxx>
>     Link: https://lkml.kernel.org/n/tip-qfwuih8cvmk9doh7k5k244eq@xxxxxxxxxxxxxx
>     Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

works for me

Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>

thanks,
jirka