kconfig: fix memory leak from range properties

Currently, sym_validate_range() duplicates the range string using xstrdup(), which is overwritten by a subsequent sym_calc_value() call. It results in a memory leak. Instead, only the pointer should be copied. Below is a test case, with a summary from Valgrind. [Test Kconfig] config FOO int "foo" range 10 20 [Test .config] CONFIG_FOO=0 [Before] LEAK SUMMARY: definitely lost: 3 bytes in 1 blocks indirectly lost: 0 bytes in 0 blocks possibly lost: 0 bytes in 0 blocks still reachable: 17,465 bytes in 21 blocks suppressed: 0 bytes in 0 blocks [After] LEAK SUMMARY: definitely lost: 0 bytes in 0 blocks indirectly lost: 0 bytes in 0 blocks possibly lost: 0 bytes in 0 blocks still reachable: 17,462 bytes in 20 blocks suppressed: 0 bytes in 0 blocks

Masahiro Yamada committed 2 years ago

Commit ae1eff01 parent 76020731 file · +6 −8Browse files

Unified · Split

scripts/kconfig/symbol.c+6−8

@@ -122,9 +122,9 @@ static long long sym_get_range_val(struct symbol *sym, int base) · 121 unmodified lines
122	122	static void sym_validate_range(struct symbol *sym)
123	123	{
124	124	struct property *prop;
	125	+ struct symbol *range_sym;
125	126	int base;
126	127	long long val, val2;
127		− char str[64];
128	128
129	129	switch (sym->type) {
130	130	case S_INT:
@@ -140,17 +140,15 @@ static void sym_validate_range(struct symbol *sym) · 9 unmodified lines
140	140	if (!prop)
141	141	return;
142	142	val = strtoll(sym->curr.val, NULL, base);
143		− val2 = sym_get_range_val(prop->expr->left.sym, base);
	143	+ range_sym = prop->expr->left.sym;
	144	+ val2 = sym_get_range_val(range_sym, base);
144	145	if (val >= val2) {
145		− val2 = sym_get_range_val(prop->expr->right.sym, base);
	146	+ range_sym = prop->expr->right.sym;
	147	+ val2 = sym_get_range_val(range_sym, base);
146	148	if (val <= val2)
147	149	return;
148	150	}
149		− if (sym->type == S_INT)
150		− sprintf(str, "%lld", val2);
151		− else
152		− sprintf(str, "0x%llx", val2);
153		− sym->curr.val = xstrdup(str);
	151	+ sym->curr.val = range_sym->curr.val;
154	152	}
155	153
156	154	static void sym_set_changed(struct symbol *sym)