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From: Nick Desaulniers <ndesaulniers@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.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>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>,
	drbd-dev@lists.linbit.com, linux-block@vger.kernel.org,
	b43-dev@lists.infradead.org,
	Network Development <netdev@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	linux-ide@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-spi@vger.kernel.org,
	Linux Memory Management List <linux-mm@kvack.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 04/10] rtlwifi: rtl8192cu: Remove uninitialized_var() usage
Date: Thu, 4 Jun 2020 13:16:08 -0700	[thread overview]
Message-ID: <CAKwvOdnd30bcqoNXF1ugadU=KbW3aXu07+T-891amO2_b7kQdg@mail.gmail.com> (raw)
In-Reply-To: <20200603233203.1695403-5-keescook@chromium.org>

On Wed, Jun 3, 2020 at 4:32 PM Kees Cook <keescook@chromium.org> wrote:
>
> 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/
>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Fixes: dc0313f46664 ("rtlwifi: rtl8192cu: Add routine hw")

> ---
>  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);

Whew! Nothing like passing the same value 6 times! (Other callers do
use distinct values though, just curious seeing this instance.)

-- 
Thanks,
~Nick Desaulniers

  reply	other threads:[~2020-06-04 20:16 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03 23:31 [PATCH 00/10] Remove uninitialized_var() macro Kees Cook
2020-06-03 23:31 ` [PATCH 01/10] x86/mm/numa: Remove uninitialized_var() usage Kees Cook
2020-06-04  7:58   ` Thomas Gleixner
2020-06-04 11:41     ` Miguel Ojeda
2020-06-04 14:56       ` Kees Cook
2020-06-04 15:22         ` Miguel Ojeda
2020-06-04 14:34     ` Kees Cook
2020-06-04 21:39       ` Thomas Gleixner
2020-06-04 22:39         ` Kees Cook
2020-06-03 23:31 ` [PATCH 02/10] drbd: " Kees Cook
2020-06-04 19:56   ` Nick Desaulniers
2020-06-03 23:31 ` [PATCH 03/10] b43: " Kees Cook
2020-06-04 20:08   ` Nick Desaulniers
2020-06-04 20:18     ` Kees Cook
2020-06-04 20:25       ` Nick Desaulniers
2020-06-05  9:20   ` Kalle Valo
2020-06-03 23:31 ` [PATCH 04/10] rtlwifi: rtl8192cu: " Kees Cook
2020-06-04 20:16   ` Nick Desaulniers [this message]
2020-06-05  9:18   ` Kalle Valo
2020-06-03 23:31 ` [PATCH 05/10] ide: " Kees Cook
2020-06-04 19:29   ` Nick Desaulniers
2020-06-04 20:20     ` Kees Cook
2020-06-04 20:29       ` Nick Desaulniers
2020-06-15 19:32         ` Kees Cook
2020-06-04 20:58       ` Sedat Dilek
2020-06-03 23:31 ` [PATCH 06/10] clk: st: " Kees Cook
2020-06-04  4:38   ` Stephen Boyd
2020-06-03 23:32 ` [PATCH 07/10] spi: davinci: " Kees Cook
2020-06-04 19:40   ` Nick Desaulniers
2020-06-03 23:32 ` [PATCH 08/10] checkpatch: Remove awareness of uninitialized_var() macro Kees Cook
2020-06-04  0:02   ` Joe Perches
2020-06-04  1:40     ` Kees Cook
2020-06-04  1:47       ` Joe Perches
2020-06-04  2:44         ` Kees Cook
2020-06-04  2:53           ` Sedat Dilek
2020-06-04  3:46             ` Kees Cook
2020-06-03 23:32 ` [PATCH 09/10] treewide: Remove uninitialized_var() usage Kees Cook
2020-06-04  3:33   ` Nathan Chancellor
2020-06-04  4:02     ` Kees Cook
2020-06-04 10:45   ` Leon Romanovsky
2020-06-04 13:23   ` Jason Gunthorpe
2020-06-04 14:59     ` Kees Cook
2020-06-04 17:57       ` Jason Gunthorpe
2020-06-04 19:09       ` Geert Uytterhoeven
2020-06-05  9:25   ` Kalle Valo
2020-06-03 23:32 ` [PATCH 10/10] compiler: Remove uninitialized_var() macro Kees Cook
2020-06-04  0:00   ` Bart Van Assche
2020-06-04  0:50   ` Miguel Ojeda
2020-06-04  1:23 ` [PATCH 00/10] " Sedat Dilek
2020-06-04  1:44   ` Kees Cook
2020-06-04  1:46     ` Sedat Dilek
2020-06-04  3:33 ` Nathan Chancellor
2020-06-04  7:26   ` Sedat Dilek
2020-06-04 14:27     ` Kees Cook

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