netdev - [PATCH v2 05/16] rtlwifi: rtl8192cu: Remove uninitialized

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Date:   Fri, 19 Jun 2020 20:29:56 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     Kees Cook <keescook@...omium.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Joe Perches <joe@...ches.com>,
        Andy Whitcroft <apw@...onical.com>, x86@...nel.org,
        drbd-dev@...ts.linbit.com, linux-block@...r.kernel.org,
        b43-dev@...ts.infradead.org, netdev@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-wireless@...r.kernel.org,
        linux-ide@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-spi@...r.kernel.org, linux-mm@...ck.org,
        clang-built-linux@...glegroups.com
Subject: [PATCH v2 05/16] rtlwifi: rtl8192cu: Remove uninitialized_var() usage

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], just initialize this variable to NULL,
and avoid sending garbage by returning.

[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: dc0313f46664 ("rtlwifi: rtl8192cu: Add routine hw")
Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>
Acked-by: Kalle Valo <kvalo@...eaurora.org>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
index f070f25bb735..5b071b70bc08 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
@@ -592,7 +592,7 @@ static void _rtl92cu_init_chipn_one_out_ep_priority(struct ieee80211_hw *hw,
 						    bool wmm_enable,
 						    u8 queue_sel)
 {
-	u16 uninitialized_var(value);
+	u16 value;
 
 	switch (queue_sel) {
 	case TX_SELE_HQ:
@@ -606,7 +606,7 @@ static void _rtl92cu_init_chipn_one_out_ep_priority(struct ieee80211_hw *hw,
 		break;
 	default:
 		WARN_ON(1); /* Shall not reach here! */
-		break;
+		return;
 	}
 	_rtl92c_init_chipn_reg_priority(hw, value, value, value, value,
 					value, value);
-- 
2.25.1