[PATCH v2 03/16] drbd: Remove uninitialized_var() usage

Kees Cook
2020-06-20T03:33:57Z

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings (e.g.
"unused variable"). If the compiler thinks it is uninitialized, either
simply initialize the variable or make compiler changes. As a precursor
to removing[2] this[3] macro[4], just initialize this variable to NULL.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Fixes: a29728463b25 ("drbd: Backport the "events2" command")
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/block/drbd/drbd_state.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index eeaa3b49b264..0067d328f0b5 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -1604,7 +1604,7 @@ static void broadcast_state_change(struct drbd_state_change *state_change)
unsigned int n_device, n_connection, n_peer_device, n_peer_devices;
void (*last_func)(struct sk_buff *, unsigned int, void *,
enum drbd_notification_type) = NULL;
- void *uninitialized_var(last_arg);
+ void *last_arg = NULL;

#define HAS_CHANGED(state) ((state)[OLD] != (state)[NEW])
#define FINAL_STATE_CHANGE(type) \
--
2.25.1