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From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Joe Perches <joe@perches.com>, Andy Whitcroft <apw@canonical.com>,
	x86@kernel.org, drbd-dev@lists.linbit.com,
	linux-block@vger.kernel.org, b43-dev@lists.infradead.org,
	netdev@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-wireless@vger.kernel.org, linux-ide@vger.kernel.org,
	linux-clk@vger.kernel.org, linux-spi@vger.kernel.org,
	linux-mm@kvack.org, clang-built-linux@googlegroups.com
Subject: [PATCH v2 09/16] clk: spear: Remove uninitialized_var() usage
Date: Fri, 19 Jun 2020 20:30:00 -0700	[thread overview]
Message-ID: <20200620033007.1444705-10-keescook@chromium.org> (raw)
In-Reply-To: <20200620033007.1444705-1-keescook@chromium.org>

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


  parent reply	other threads:[~2020-06-20  3:31 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-20  3:29 [PATCH v2 00/16] Remove uninitialized_var() macro Kees Cook
2020-06-20  3:29 ` [PATCH v2 01/16] docs: deprecated.rst: Add uninitialized_var() Kees Cook
2020-06-22 16:59   ` Nick Desaulniers
2020-06-22 16:59     ` Nick Desaulniers
2020-06-22 16:59     ` Nick Desaulniers
2020-06-20  3:29 ` [PATCH v2 02/16] x86/mm/numa: Remove uninitialized_var() usage Kees Cook
2020-06-20  3:29 ` [PATCH v2 03/16] drbd: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 04/16] b43: " Kees Cook
2020-06-22 17:04   ` Nick Desaulniers
2020-06-22 17:04     ` Nick Desaulniers
2020-06-22 17:04     ` Nick Desaulniers
2020-06-22 21:04     ` Kees Cook
2020-06-22 21:04       ` Kees Cook
2020-06-23 18:29       ` Nick Desaulniers
2020-06-23 18:29         ` Nick Desaulniers
2020-06-23 18:29         ` Nick Desaulniers
2020-07-15 10:37   ` Kalle Valo
2020-07-15 10:37   ` Kalle Valo
2020-07-15 10:37   ` Kalle Valo
2020-06-20  3:29 ` [PATCH v2 05/16] rtlwifi: rtl8192cu: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 06/16] ide: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 07/16] clk: st: " Kees Cook
2020-06-22  9:03   ` Stephen Boyd
2020-06-22  9:03     ` Stephen Boyd
2020-06-20  3:29 ` [PATCH v2 08/16] spi: davinci: " Kees Cook
2020-07-01 20:39   ` Mark Brown
2020-07-01 20:39     ` Mark Brown
2020-07-02 15:21     ` Kees Cook
2020-07-02 15:21       ` Kees Cook
2020-07-02 15:23       ` Mark Brown
2020-07-02 15:23         ` Mark Brown
2020-07-02 15:42         ` Kees Cook
2020-07-02 15:42           ` Kees Cook
2020-07-02 16:23           ` Joe Perches
2020-07-02 16:23             ` Joe Perches
2020-07-02 16:23             ` Joe Perches
2020-06-20  3:30 ` Kees Cook [this message]
2020-06-22  9:03   ` [PATCH v2 09/16] clk: spear: " Stephen Boyd
2020-06-22  9:03     ` Stephen Boyd
2020-06-20  3:30 ` [PATCH v2 10/16] KVM: PPC: Book3S PR: " Kees Cook
2020-06-22 17:22   ` Nick Desaulniers
2020-06-22 17:22     ` Nick Desaulniers
2020-06-22 17:22     ` Nick Desaulniers
2020-06-20  3:30 ` [PATCH v2 11/16] media: sur40: " Kees Cook
2020-06-22 18:39   ` Nick Desaulniers
2020-06-22 18:39     ` Nick Desaulniers
2020-06-22 18:39     ` Nick Desaulniers
2020-06-20  3:30 ` [PATCH v2 12/16] f2fs: Eliminate usage of uninitialized_var() macro Kees Cook
2020-06-20  3:30 ` [PATCH v2 14/16] checkpatch: Remove awareness " Kees Cook
2020-06-20  3:30 ` [PATCH v2 15/16] treewide: Remove uninitialized_var() usage Kees Cook
2020-06-22 11:32   ` Dan Carpenter
2020-06-22 11:32     ` Dan Carpenter
2020-06-20  3:30 ` [PATCH v2 16/16] compiler: Remove uninitialized_var() macro Kees Cook
2020-06-20  3:30 ` [PATCH v2 13/16] mm/debug_vm_pgtable: Remove uninitialized_var() usage Kees Cook
2020-06-22 17:27   ` Nick Desaulniers
2020-06-22 17:27     ` Nick Desaulniers
2020-06-22 17:27     ` Nick Desaulniers
2020-06-20  7:03 ` [PATCH v2 00/16] Remove uninitialized_var() macro Sedat Dilek
2020-06-20  7:03   ` Sedat Dilek
2020-06-20 15:57   ` Kees Cook
2020-06-22  9:07     ` Sedat Dilek
2020-06-22  9:07       ` Sedat Dilek
2020-06-22  9:07       ` Sedat Dilek

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