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

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

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@redhat.com>
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@mns.spb.ru>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Kirill Smelkov <kirr@mns.spb.ru>
    Cc: Mike Galbraith <efault@gmx.de>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Tom Zanussi <tzanussi@gmail.com>
    LKML-Reference: <new-submission>
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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));