[PATCH] perf c2c report: Properly check data presence in rb_tree loop

Jiri Olsa
2016-10-21T00:17:16Z

On Thu, Oct 20, 2016 at 06:02:24PM -0500, Kim Phillips wrote:

SNIP

> (gdb) bt
> #0 c2c_browser__update_nr_entries (hb=<optimized out>, hb=<optimized out>) at builtin-c2c.c:2142
> #1 perf_c2c__hists_browse (hists=0x8b2d90 <c2c+240>) at builtin-c2c.c:2287
> #2 perf_c2c_display (session=0x205b1a0) at builtin-c2c.c:2316
> #3 perf_c2c__report (argv=<optimized out>, argc=<optimized out>) at builtin-c2c.c:2621
> #4 cmd_c2c (argc=<optimized out>, argv=<optimized out>, prefix=<optimized out>) at builtin-c2c.c:2748
> #5 0x000000000048df61 in run_builtin (p=p@entry=0x8be168 <commands+72>, argc=argc@entry=2, argv=argv@entry=0x7fffffffddb0)
> at perf.c:358
> #6 0x00000000004249b6 in handle_internal_command (argv=0x7fffffffddb0, argc=2) at perf.c:420
> #7 run_argv (argv=0x7fffffffdb40, argcp=0x7fffffffdb4c) at perf.c:466
> #8 main (argc=2, argv=0x7fffffffddb0) at perf.c:610
> (gdb)
>
> All the above work fine when run under sudo.

ugh, stupid mistake.. attached patch fixes that for me

thanks,
jirka

---
Kim reported crash when there's no data stored. In this case
the TUI code crashes in c2c_browser__update_nr_entries, because
we dont check the initial rb_tree node for NULL.

Adding the missing check.

Reported-by: Kim Phillips <kim.phillips@arm.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/builtin-c2c.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index dc4f0636dfa1..c6d0dda594d9 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2135,14 +2135,14 @@ static void c2c_browser__update_nr_entries(struct hist_browser *hb)
u64 nr_entries = 0;
struct rb_node *nd = rb_first(&hb->hists->entries);

- do {
+ while (nd) {
struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);

if (!he->filtered)
nr_entries++;

nd = rb_next(nd);
- } while (nd);
+ }

hb->nr_non_filtered_entries = nr_entries;
}
--
2.7.4