[PATCH v2 09/16] clk: spear: Remove uninitialized_var() usage

Kees Cook
2020-06-20T03:32:46Z

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], initialize "i" to zero. The compiler
warning was not a false positive, since clk_pll_set_rate()'s call to
clk_pll_round_rate_index() will always fail (since "prate" is NULL), so
"i" was never being initialized.

[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: 7d4998f71b29 ("clk: SPEAr: Vco-pll: Fix compilation warning")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/clk/spear/clk-vco-pll.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/spear/clk-vco-pll.c b/drivers/clk/spear/clk-vco-pll.c
index c08dec30bfa6..fed194169666 100644
--- a/drivers/clk/spear/clk-vco-pll.c
+++ b/drivers/clk/spear/clk-vco-pll.c
@@ -147,7 +147,7 @@ static int clk_pll_set_rate(struct clk_hw *hw, unsigned long drate,
struct clk_pll *pll = to_clk_pll(hw);
struct pll_rate_tbl *rtbl = pll->vco->rtbl;
unsigned long flags = 0, val;
- int uninitialized_var(i);
+ int i = 0;

clk_pll_round_rate_index(hw, drate, NULL, &i);

--
2.25.1