From: Masahiro Yamada <masahiroy@kernel.org> To: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Cc: Linus Walleij <linus.walleij@linaro.org>, Bartosz Golaszewski <bgolaszewski@baylibre.com>, "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Subject: Re: [PATCH] gpio: uniphier: Replace zero-length array with flexible-array member Date: Tue, 18 Feb 2020 10:25:08 +0900 [thread overview] Message-ID: <CAK7LNASABqhpCjoQkQAZAVOjTvVG+4PDWaP+a8=hcv6GsgeQMQ@mail.gmail.com> (raw) In-Reply-To: <20200211210618.GA29823@embeddedor> On Wed, Feb 12, 2020 at 6:03 AM Gustavo A. R. Silva <gustavo@embeddedor.com> wrote: > > The current codebase makes use of the zero-length array language > extension to the C90 standard, but the preferred mechanism to declare > variable-length types such as these ones is a flexible array member[1][2], > introduced in C99: > > struct foo { > int stuff; > struct boo array[]; > }; > > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last in the structure, which > will help us prevent some kind of undefined behavior bugs from being > inadvertenly introduced[3] to the codebase from now on. > > This issue was found with the help of Coccinelle. > > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > [2] https://github.com/KSPP/linux/issues/21 > [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > drivers/gpio/gpio-uniphier.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpio-uniphier.c b/drivers/gpio/gpio-uniphier.c > index 0f662b297a95..9843638d99d0 100644 > --- a/drivers/gpio/gpio-uniphier.c > +++ b/drivers/gpio/gpio-uniphier.c > @@ -33,7 +33,7 @@ struct uniphier_gpio_priv { > struct irq_domain *domain; > void __iomem *regs; > spinlock_t lock; > - u32 saved_vals[0]; > + u32 saved_vals[]; > }; > > static unsigned int uniphier_gpio_bank_to_reg(unsigned int bank) > -- > 2.25.0 > -- Best Regards Masahiro Yamada
WARNING: multiple messages have this Message-ID (diff)
From: Masahiro Yamada <masahiroy@kernel.org> To: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>, Linus Walleij <linus.walleij@linaro.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org> Subject: Re: [PATCH] gpio: uniphier: Replace zero-length array with flexible-array member Date: Tue, 18 Feb 2020 10:25:08 +0900 [thread overview] Message-ID: <CAK7LNASABqhpCjoQkQAZAVOjTvVG+4PDWaP+a8=hcv6GsgeQMQ@mail.gmail.com> (raw) In-Reply-To: <20200211210618.GA29823@embeddedor> On Wed, Feb 12, 2020 at 6:03 AM Gustavo A. R. Silva <gustavo@embeddedor.com> wrote: > > The current codebase makes use of the zero-length array language > extension to the C90 standard, but the preferred mechanism to declare > variable-length types such as these ones is a flexible array member[1][2], > introduced in C99: > > struct foo { > int stuff; > struct boo array[]; > }; > > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last in the structure, which > will help us prevent some kind of undefined behavior bugs from being > inadvertenly introduced[3] to the codebase from now on. > > This issue was found with the help of Coccinelle. > > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > [2] https://github.com/KSPP/linux/issues/21 > [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > drivers/gpio/gpio-uniphier.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpio-uniphier.c b/drivers/gpio/gpio-uniphier.c > index 0f662b297a95..9843638d99d0 100644 > --- a/drivers/gpio/gpio-uniphier.c > +++ b/drivers/gpio/gpio-uniphier.c > @@ -33,7 +33,7 @@ struct uniphier_gpio_priv { > struct irq_domain *domain; > void __iomem *regs; > spinlock_t lock; > - u32 saved_vals[0]; > + u32 saved_vals[]; > }; > > static unsigned int uniphier_gpio_bank_to_reg(unsigned int bank) > -- > 2.25.0 > -- Best Regards Masahiro Yamada _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-02-18 1:25 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-11 21:06 [PATCH] gpio: uniphier: Replace zero-length array with flexible-array member Gustavo A. R. Silva 2020-02-11 21:06 ` Gustavo A. R. Silva 2020-02-17 9:38 ` Bartosz Golaszewski 2020-02-17 9:38 ` Bartosz Golaszewski 2020-02-18 1:25 ` Masahiro Yamada [this message] 2020-02-18 1:25 ` Masahiro Yamada
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