[tip:perf/urgent] perf hists: Add extra integrity checks to fmt_free()

[tip-bot for Jiri Olsa <tipbot@zytor.com>]

Commit-ID:  d0e35234f647631ddfa5fa8c8ec66c9bc698f0ab
Gitweb:     https://git.kernel.org/tip/d0e35234f647631ddfa5fa8c8ec66c9bc698f0ab
Author:     Jiri Olsa <jolsa@kernel.org>
AuthorDate: Fri, 13 Oct 2017 10:37:29 +0200
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 13 Oct 2017 16:43:42 -0300

perf hists: Add extra integrity checks to fmt_free()

Make sure the struct perf_hpp_fmt is properly unhooked before we free
it.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Changbin Du <changbin.du@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20171013083736.15037-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/ui/hist.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 6ee6b36..db79017 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -606,6 +606,13 @@ next:
 
 static void fmt_free(struct perf_hpp_fmt *fmt)
 {
+	/*
+	 * At this point fmt should be completely
+	 * unhooked, if not it's a bug.
+	 */
+	BUG_ON(!list_empty(&fmt->list));
+	BUG_ON(!list_empty(&fmt->sort_list));
+
 	if (fmt->free)
 		fmt->free(fmt);
 }