kconfig: don't crash on NULL expressions in expr_eq()

NULL expressions are taken to always be true, as implemented by the
expr_is_yes() macro and by several other functions in expr.c. As such,
they ought to be valid inputs to expr_eq(), which compares two
expressions.

Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This commit is contained in:
Thomas Hebb 2019-12-09 00:19:17 -08:00 committed by Masahiro Yamada
parent fd2ab2f661
commit 272a721030
1 changed files with 7 additions and 0 deletions

View File

@ -254,6 +254,13 @@ static int expr_eq(struct expr *e1, struct expr *e2)
{
int res, old_count;
/*
* A NULL expr is taken to be yes, but there's also a different way to
* represent yes. expr_is_yes() checks for either representation.
*/
if (!e1 || !e2)
return expr_is_yes(e1) && expr_is_yes(e2);
if (e1->type != e2->type)
return 0;
switch (e1->type) {