[PATCH 2/2] perf c2c: Clean up registered formats on c2c_hists__init() and c2c_hists__reinit() failure

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

When c2c_hists__init() or c2c_hists__reinit() calls hpp_list__parse()
and it fails partway through, format structures registered via
perf_hpp_list__column_register() and perf_hpp_list__register_sort_field()
are left on the hpp_list.

In c2c_hists__init(), the c2c_he__alloc_hists() caller handles this with
perf_hpp__reset_output_field(), but perf_c2c_report() does not, leaking
the partially registered entries.

In c2c_hists__reinit(), neither perf_c2c_report() nor resort_cl_cb()
clean up on failure.

Fix by adding cleanup inside both functions themselves, so all callers
are protected.

Fixes: 78b275437873 ("perf c2c report: Add sample processing")
Reported-by: sashiko-bot <sashiko-bot@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Assisted-by: Claude:claude-opus-4.6
Assisted-by: Opencode:mimo-v2.5-free
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-c2c.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 160b82694d391c50..1856cccbee27818b 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2147,6 +2147,8 @@ static int c2c_hists__init(struct c2c_hists *hists,
 			   int nr_header_lines,
 			   struct perf_env *env)
 {
+	int ret;
+
 	__hists__init(&hists->hists, &hists->list);
 
 	/*
@@ -2159,7 +2161,13 @@ static int c2c_hists__init(struct c2c_hists *hists,
 	/* Overload number of header lines.*/
 	hists->list.nr_header_lines = nr_header_lines;
 
-	return hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
+	ret = hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
+
+	/* Unregister any formats added before the failure point */
+	if (ret)
+		perf_hpp__reset_output_field(&hists->list);
+
+	return ret;
 }
 
 static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
@@ -2167,8 +2175,16 @@ static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
 			     const char *sort,
 			     struct perf_env *env)
 {
+	int ret;
+
 	perf_hpp__reset_output_field(&c2c_hists->list);
-	return hpp_list__parse(&c2c_hists->list, output, sort, env);
+	ret = hpp_list__parse(&c2c_hists->list, output, sort, env);
+
+	/* Unregister any formats added before the failure point */
+	if (ret)
+		perf_hpp__reset_output_field(&c2c_hists->list);
+
+	return ret;
 }
 
 #define DISPLAY_LINE_LIMIT  0.001
-- 
2.55.0