diff options
| author | Dirk Gouders <dirk@gouders.net> | 2013-05-21 10:54:11 +0200 |
|---|---|---|
| committer | Yann E. MORIN <yann.morin.1998@free.fr> | 2013-05-30 00:14:01 +0200 |
| commit | e983b7b17ad1a978e954e6aaa62cf12bfc747883 (patch) | |
| tree | d03b6ef41719ff23f7228ce7f32c8a352b3bc070 /scripts/kconfig | |
| parent | 063f4661fde8c03c4c03f8a205071a52691c152e (diff) | |
| download | linux-e983b7b17ad1a978e954e6aaa62cf12bfc747883.tar.bz2 | |
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.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c index b5c7d90df9df..fd3f0180e08f 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); } } |