[PATCH 1/1] perf callchain: Use zfree() to avoid possibly accessing dangling pointers

From: Arnaldo Carvalho de Melo
Date: Mon May 06 2024 - 23:12:39 EST


When freeing a->b it is good practice to set a->b to NULL using
zfree(&a->b) so that when we have a bug where a reference to a freed 'a'
pointer is kept somewhere, we can more quickly cause a segfault if some
code tries to use a->b.

Convert one such case in the callchain code.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/callchain.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 68feed8718096f78..1730b852a947400f 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -606,7 +606,7 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
call->brtype_stat = zalloc(sizeof(*call->brtype_stat));
if (!call->brtype_stat) {
perror("not enough memory for the code path branch statistics");
- free(call->brtype_stat);
+ zfree(&call->brtype_stat);
return -ENOMEM;
}
}
--
2.44.0