[PATCH v2 04/16] b43: Remove uninitialized_var() usage

Kees Cook
2020-06-20T03:30:39Z

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.
No later NULL deref is possible due to the early returns outside of the
(phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for 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: 58619b14d106 ("b43: move under broadcom vendor directory")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/net/wireless/broadcom/b43/phy_n.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
index c33b4235839d..46db91846007 100644
--- a/drivers/net/wireless/broadcom/b43/phy_n.c
+++ b/drivers/net/wireless/broadcom/b43/phy_n.c
@@ -4222,7 +4222,7 @@ static void b43_nphy_tx_gain_table_upload(struct b43_wldev *dev)
u32 rfpwr_offset;
u8 pga_gain, pad_gain;
int i;
- const s16 *uninitialized_var(rf_pwr_offset_table);
+ const s16 *rf_pwr_offset_table = NULL;

table = b43_nphy_get_tx_gain_table(dev);
if (!table)
--
2.25.1