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

2020-06-22 Thread Stephen Boyd
Quoting Kees Cook (2020-06-19 20:30:00)
> 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-gli...@google.com/
> [2] 
> https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1tgqcr5vqkczwj0qxk6cernou6eedsuda...@mail.gmail.com/
> [3] 
> https://lore.kernel.org/lkml/ca+55afwgbgqhbp1fkxvrkepzyr5j8n1vkt1vzdz9knmpuxh...@mail.gmail.com/
> [4] 
> https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yvju65tplgn_ybynv0ve...@mail.gmail.com/
> 
> Fixes: 7d4998f71b29 ("clk: SPEAr: Vco-pll: Fix compilation warning")
> Signed-off-by: Kees Cook 
> ---

Acked-by: Stephen Boyd 


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

2020-06-19 Thread Kees Cook
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-gli...@google.com/
[2] 
https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1tgqcr5vqkczwj0qxk6cernou6eedsuda...@mail.gmail.com/
[3] 
https://lore.kernel.org/lkml/ca+55afwgbgqhbp1fkxvrkepzyr5j8n1vkt1vzdz9knmpuxh...@mail.gmail.com/
[4] 
https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yvju65tplgn_ybynv0ve...@mail.gmail.com/

Fixes: 7d4998f71b29 ("clk: SPEAr: Vco-pll: Fix compilation warning")
Signed-off-by: Kees Cook 
---
 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, );
 
-- 
2.25.1