[PATCH AUTOSEL for 4.14 047/161] kconfig: Fix automatic menu creation mem leak

Sasha Levin
2018-04-09T03:20:37Z

From: Ulf Magnusson <ulfalizer@gmail.com>

[ Upstream commit ae7440ef0c8013d68c00dad6900e7cce5311bb1c ]

expr_trans_compare() always allocates and returns a new expression,
giving the following leak outline:

...
*Allocate*
basedep = expr_trans_compare(basedep, E_UNEQUAL, &symbol_no);
...
for (menu = parent->next; menu; menu = menu->next) {
...
*Copy*
dep2 = expr_copy(basedep);
...
*Free copy*
expr_free(dep2);
}
*basedep lost!*

Fix by freeing 'basedep' after the loop.

Summary from Valgrind on 'menuconfig' (ARCH=x86) before the fix:

LEAK SUMMARY:
definitely lost: 344,376 bytes in 14,349 blocks
...

Summary after the fix:

LEAK SUMMARY:
definitely lost: 44,448 bytes in 1,852 blocks
...

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
scripts/kconfig/menu.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index e9357931b47d..749c2bd5fc51 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -372,6 +372,7 @@ void menu_finalize(struct menu *parent)
menu->parent = parent;
last_menu = menu;
}
+ expr_free(basedep);
if (last_menu) {
parent->list = parent->next;
parent->next = last_menu->next;
--
2.15.1