Thread (35 messages) 35 messages, 7 authors, 2020-07-15
STALE2170d
Revisions (2)
  1. v1 [diff vs current]
  2. v2 current

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

From: Kees Cook <hidden>
Date: 2020-06-20 03:32:46
Also in: linux-block, linux-clk, linux-doc, linux-ide, linux-mm, linux-spi, linux-wireless, lkml
Subsystem: common clk framework, spear platform/clock/pinctrl support, the rest · Maintainers: Michael Turquette, Stephen Boyd, Viresh Kumar, Linus Torvalds

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

Fixes: 7d4998f71b29 ("clk: SPEAr: Vco-pll: Fix compilation warning")
Signed-off-by: Kees Cook <redacted>
---
 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
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