Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751415AbdINNin (ORCPT ); Thu, 14 Sep 2017 09:38:43 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:36159 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751133AbdINNim (ORCPT ); Thu, 14 Sep 2017 09:38:42 -0400 X-Google-Smtp-Source: ADKCNb58dwCPkAGC2ADN2JapLBfzQIkH6VIbIC/bYVf1ph6n3TIwBCtLTybC2n6XoBDSreJpCcg60MWgA305Vpq/ABY= MIME-Version: 1.0 In-Reply-To: <20170914110709.3591691-1-arnd@arndb.de> References: <20170914110709.3591691-1-arnd@arndb.de> From: Geert Uytterhoeven Date: Thu, 14 Sep 2017 15:38:41 +0200 X-Google-Sender-Auth: jPm4cHGBd26n_wwIh6NWwHVrKys Message-ID: Subject: Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code To: Arnd Bergmann Cc: Cyrille Pitchen , Marek Vasut , Boris Brezillon , Alexandre Torgue , Richard Weinberger , "linux-kernel@vger.kernel.org" , MTD Maling List , "linux-arm-kernel@lists.infradead.org" , Maxime Coquelin , Brian Norris , David Woodhouse , Ludovic Barre Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8EDcnt8001982 Content-Length: 1899 Lines: 50 Hi Arnd, On Thu, Sep 14, 2017 at 1:06 PM, Arnd Bergmann 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 > --- > 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