[tip:perf/core] perf top: Fix freeze on --call-graph flat/folded

[tip-bot for Namhyung Kim <tipbot@zytor.com>]

Commit-ID:  0356218a68551f051998f4fb5074a1eed7a346fe
Gitweb:     http://git.kernel.org/tip/0356218a68551f051998f4fb5074a1eed7a346fe
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Thu, 26 Nov 2015 16:08:18 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 26 Nov 2015 13:32:08 -0300

perf top: Fix freeze on --call-graph flat/folded

The callchain rbtree is rebuilt periodically, so it needs to
reinitialize the root everytime.  Otherwise it can be stuck in the
rbtree insertion with stale pointers.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1448521700-32062-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/callchain.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index fc3b1e0..564377d 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -290,6 +290,7 @@ static void
 sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
 		u64 min_hit, struct callchain_param *param __maybe_unused)
 {
+	*rb_root = RB_ROOT;
 	__sort_chain_flat(rb_root, &root->node, min_hit);
 }