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authorDirk Gouders <dirk@gouders.net>2013-05-21 10:54:11 +0200
committerYann E. MORIN <yann.morin.1998@free.fr>2013-05-30 00:14:01 +0200
commite983b7b17ad1a978e954e6aaa62cf12bfc747883 (patch)
treed03b6ef41719ff23f7228ce7f32c8a352b3bc070 /scripts/kconfig
parent063f4661fde8c03c4c03f8a205071a52691c152e (diff)
downloadlinaro-lsk-e983b7b17ad1a978e954e6aaa62cf12bfc747883.tar.gz
kconfig/menu.c: fix multiple references to expressions in menu_add_prop()
menu_add_prop() applies upper menus' visibilities to actual prompts by AND-ing the prompts visibilities with the upper menus ones. This creates a further reference to the menu's visibilities and when the expression reduction functions do their work, they may remove or modify expressions that have multiple references, thus causing unpredictable side-effects. The following example Kconfig constructs a case where this causes problems: a menu and a prompt which's visibilities depend on the same symbol. When invoking mconf with this Kconfig and pressing "Z" we see a problem caused by a free'd expression still referenced by the menu's visibility: ------------------------------------------------------------------------ mainmenu "Kconfig Testing Configuration" config VISIBLE def_bool n config Placeholder bool "Place holder" menu "Invisible" visible if VISIBLE config TEST_VAR bool "Test option" if VISIBLE endmenu ------------------------------------------------------------------------ This patch fixes this problem by creating copies of the menu's visibility expressions before AND-ing them with the prompt's one. Signed-off-by: Dirk Gouders <dirk@gouders.net> [yann.morin.1998@free.fr: move variable into its block-scope, keep lines <80 chars, typo] Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Diffstat (limited to 'scripts/kconfig')
-rw-r--r--scripts/kconfig/menu.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index b5c7d90df9d..fd3f0180e08 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -146,11 +146,24 @@ struct property *menu_add_prop(enum prop_type type, char *prompt, struct expr *e
struct menu *menu = current_entry;
while ((menu = menu->parent) != NULL) {
+ struct expr *dup_expr;
+
if (!menu->visibility)
continue;
+ /*
+ * Do not add a reference to the
+ * menu's visibility expression but
+ * use a copy of it. Otherwise the
+ * expression reduction functions
+ * will modify expressions that have
+ * multiple references which can
+ * cause unwanted side effects.
+ */
+ dup_expr = expr_copy(menu->visibility);
+
prop->visible.expr
= expr_alloc_and(prop->visible.expr,
- menu->visibility);
+ dup_expr);
}
}