diff --git a/builtin/config.c b/builtin/config.c
index 0015620dde..40456c0770 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -44,7 +44,7 @@ static struct config_options config_options;
 static int show_origin;
 static int show_scope;
 static int fixed_value;
-static const char *comment;
+static const char *comment_arg;
 
 #define ACTION_GET (1<<0)
 #define ACTION_GET_ALL (1<<1)
@@ -174,7 +174,7 @@ static struct option builtin_config_options[] = {
 	OPT_BOOL(0, "show-origin", &show_origin, N_("show origin of config (file, standard input, blob, command line)")),
 	OPT_BOOL(0, "show-scope", &show_scope, N_("show scope of config (worktree, local, global, system, command)")),
 	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
-	OPT_STRING(0, "comment", &comment, N_("value"), N_("human-readable comment string (# will be prepended as needed)")),
+	OPT_STRING(0, "comment", &comment_arg, N_("value"), N_("human-readable comment string (# will be prepended as needed)")),
 	OPT_END(),
 };
 
@@ -674,7 +674,7 @@ static char *default_user_config(void)
 int cmd_config(int argc, const char **argv, const char *prefix)
 {
 	int nongit = !startup_info->have_repository;
-	char *value = NULL;
+	char *value = NULL, *comment = NULL;
 	int flags = 0;
 	int ret = 0;
 	struct key_value_info default_kvi = KVI_INIT;
@@ -799,7 +799,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		usage_builtin_config();
 	}
 
-	if (comment &&
+	if (comment_arg &&
 	    !(actions & (ACTION_ADD|ACTION_SET|ACTION_SET_ALL|ACTION_REPLACE_ALL))) {
 		error(_("--comment is only applicable to add/set/replace operations"));
 		usage_builtin_config();
@@ -841,7 +841,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		flags |= CONFIG_FLAGS_FIXED_VALUE;
 	}
 
-	comment = git_config_prepare_comment_string(comment);
+	comment = git_config_prepare_comment_string(comment_arg);
 
 	if (actions & PAGING_ACTIONS)
 		setup_auto_pager("config", 1);
@@ -993,6 +993,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		return get_colorbool(argv[0], argc == 2);
 	}
 
+	free(comment);
 	free(value);
 	return ret;
 }
diff --git a/config.c b/config.c
index ae3652b08f..13cf9eeb16 100644
--- a/config.c
+++ b/config.c
@@ -3182,14 +3182,10 @@ void git_config_set(const char *key, const char *value)
 	trace2_cmd_set_config(key, value);
 }
 
-/*
- * The ownership rule is that the caller will own the string
- * if it receives a piece of memory different from what it passed
- * as the parameter.
- */
-const char *git_config_prepare_comment_string(const char *comment)
+char *git_config_prepare_comment_string(const char *comment)
 {
 	size_t leading_blanks;
+	char *prepared;
 
 	if (!comment)
 		return NULL;
@@ -3210,13 +3206,13 @@ const char *git_config_prepare_comment_string(const char *comment)
 
 	leading_blanks = strspn(comment, " \t");
 	if (leading_blanks && comment[leading_blanks] == '#')
-		; /* use it as-is */
+		prepared = xstrdup(comment); /* use it as-is */
 	else if (comment[0] == '#')
-		comment = xstrfmt(" %s", comment);
+		prepared = xstrfmt(" %s", comment);
 	else
-		comment = xstrfmt(" # %s", comment);
+		prepared = xstrfmt(" # %s", comment);
 
-	return comment;
+	return prepared;
 }
 
 static void validate_comment_string(const char *comment)
diff --git a/config.h b/config.h
index f4966e3749..db8b608064 100644
--- a/config.h
+++ b/config.h
@@ -338,7 +338,7 @@ void git_config_set_multivar(const char *, const char *, const char *, unsigned)
 int repo_config_set_multivar_gently(struct repository *, const char *, const char *, const char *, unsigned);
 int git_config_set_multivar_in_file_gently(const char *, const char *, const char *, const char *, const char *, unsigned);
 
-const char *git_config_prepare_comment_string(const char *);
+char *git_config_prepare_comment_string(const char *);
 
 /**
  * takes four parameters: