| Message ID | 20200620033007.1444705-10-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | Remove uninitialized_var() macro | expand |
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-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> > --- Acked-by: Stephen Boyd <sboyd@kernel.org>
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);
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(-)