Re: [BUG] perf top -> annotate broken; bisected to 69aad6f1

[Kirill Smelkov]

On Tue, Jan 11, 2011 at 03:23:10PM -0200, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 11, 2011 at 03:11:24PM -0200, Arnaldo Carvalho de Melo escreveu:
> > Em Tue, Jan 11, 2011 at 07:35:20PM +0300, Kirill Smelkov escreveu:
> > > Hello up there,
> > > 
> > > Since 69aad6f1ee69546dea8535ab8f3da9f445d57328 (perf tools: Introduce
> > > event selectors; Jan 3 2011) annotating a symbol in perf top segfaults:
> > > 
> > >     Program received signal SIGSEGV, Segmentation fault.
> > >     [Switching to Thread 0xb714cb90 (LWP 4662)]
> > >     event_name (evsel=0x0) at util/parse-events.c:274
> > >     274             return __event_name(type, config);
> > >     (gdb) bt
> > >     #0  event_name (evsel=0x0) at util/parse-events.c:274
> > >     #1  0x0805f892 in display_thread (arg=0x9422448) at builtin-top.c:359
> > >     #2  0xb77234c0 in start_thread () from /lib/i686/cmov/libpthread.so.0
> > >     #3  0xb732b84e in clone () from /lib/i686/cmov/libc.so.6
> > > 
> > > 
> > > It used to work...
> > 
> > Thanks for the report, working on a fix.
> 
> Done, please test it and I'll add a Tested-by: you tag.
> 
> Thanks,
> 
> - Arnaldo
> 
> commit 347ad46af282994524510d62a4c70455929b6a9d
> Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Date:   Tue Jan 11 15:16:52 2011 -0200
> 
>     perf top: Fix annotate segv
>     
>     Before we had sym_counter, it was initialized to zero and we used that
>     as an index in the global attrs variable, now we have a list of evsel
>     entries, and sym_counter became sym_evsel, that remained initialized to
>     zero (NULL): b00m.
>     
>     Fix it by initializing it to the first entry in the evsel list.
>     
>     Bug-introduced: 69aad6f
>     Reported-by: Kirill Smelkov <kirr@xxxxxxxxxx>
>     Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>     Cc: Ingo Molnar <mingo@xxxxxxx>
>     Cc: Kirill Smelkov <kirr@xxxxxxxxxx>
>     Cc: Mike Galbraith <efault@xxxxxx>
>     Cc: Paul Mackerras <paulus@xxxxxxxxx>
>     Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>     Cc: Stephane Eranian <eranian@xxxxxxxxxx>
>     Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
>     LKML-Reference: <new-submission>
>     Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> 
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 4b995ee..568b195 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1473,6 +1473,8 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
>  		pos->attr.sample_period = default_interval;
>  	}
>  
> +	sym_evsel = list_entry(evsel_list.next, struct perf_evsel, node);
> +
>  	symbol_conf.priv_size = (sizeof(struct sym_entry) +
>  				 (nr_counters + 1) * sizeof(unsigned long));

Now it works again, thanks!

Tested-by: Kirill Smelkov <kirr@xxxxxxxxxx>
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