[PATCH 4.9 046/329] kconfig: Fix automatic menu creation mem leak

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 10:47:05 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ulf Magnusson <ulfalizer@xxxxxxxxx>

[ 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@xxxxxxxxx>
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
scripts/kconfig/menu.c | 1 +
1 file changed, 1 insertion(+)

--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -364,6 +364,7 @@ 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;