From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
Marek Vasut <marek.vasut@gmail.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
Richard Weinberger <richard@nod.at>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
MTD Maling List <linux-mtd@lists.infradead.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Brian Norris <computersforpeace@gmail.com>,
David Woodhouse <dwmw2@infradead.org>,
Ludovic Barre <ludovic.barre@st.com>
Subject: Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code
Date: Thu, 14 Sep 2017 15:38:41 +0200 [thread overview]
Message-ID: <CAMuHMdU3AqGkvwDQ+hE2=3PhgCKUh1HvBx8Hkvba6XsLHAuBbg@mail.gmail.com> (raw)
In-Reply-To: <20170914110709.3591691-1-arnd@arndb.de>
Hi Arnd,
On Thu, Sep 14, 2017 at 1:06 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> If we send zero-length data to stm32_qspi_tx_poll() on older
> compiler versions such as gcc-4.6, we get warned that the
> return code is uninitialized:
>
> drivers/mtd/spi-nor/stm32-quadspi.c:248:2: error: ‘ret’ may be used uninitialized in this function [-Werror=uninitialized]
>
> On newer compiler versions, the return code is always zero
> in this case, as the local variable gets optimized away and
> is assumed to be zero after the loop completes without error.
>
> This changes the function to instead return -EINVAL if it
> ever gets called with a zero length buffer.
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82203
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/mtd/spi-nor/stm32-quadspi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
> index 86c0931543c5..711cfe7aa4bf 100644
> --- a/drivers/mtd/spi-nor/stm32-quadspi.c
> +++ b/drivers/mtd/spi-nor/stm32-quadspi.c
> @@ -227,7 +227,7 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
> void (*tx_fifo)(u8 *, void __iomem *);
> u32 len = cmd->len, sr;
> u8 *buf = cmd->buf;
> - int ret;
> + int ret = -EINVAL;
>
> if (cmd->qspimode == CCR_FMODE_INDW)
> tx_fifo = stm32_qspi_write_fifo;
See also "[PATCH] mtd: spi-nor: stm32-quadspi: Fix uninitialized error
return code"
(https://patchwork.kernel.org/patch/9842173/)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2017-09-14 13:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-14 11:06 [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code Arnd Bergmann
2017-09-14 12:38 ` Ludovic BARRE
2017-09-14 13:38 ` Geert Uytterhoeven [this message]
2017-09-14 15:13 ` Ludovic BARRE
2017-09-14 15:24 ` Geert Uytterhoeven
2017-09-14 16:55 ` Ludovic BARRE
2017-09-14 21:38 ` Arnd Bergmann
2017-09-15 7:59 ` Ludovic BARRE
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