linux-kernel - Re: [PATCH] acpi: avoid uninialized-variable warning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAHp75VfSny=nSeiCnjE8MwL=hLT92G--9qy6=_0mittzuPxc-A@mail.gmail.com>
Date:   Wed, 29 Apr 2020 01:08:30 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rob Herring <robh@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] acpi: avoid uninialized-variable warning

On Wed, Apr 29, 2020 at 1:03 AM Arnd Bergmann <arnd@...db.de> wrote:
>
> Older compilers like gcc-4.8 produce a bogus warning here
>
> In file included from include/linux/compiler_types.h:68:0,
>                  from <command-line>:0:
> drivers/acpi/property.c: In function 'acpi_data_prop_read':
> include/linux/compiler-gcc.h:75:45: error: 'obj' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>  #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
>                                              ^
> drivers/acpi/property.c:934:27: note: 'obj' was declared here
>   const union acpi_object *obj;
>                            ^
>
> Ensure the output is always initialized even when returning an error
> to avoid the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/acpi/property.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index e601c4511a8b..3aa71daeb0b4 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -587,8 +587,10 @@ static int acpi_data_get_property_array(const struct acpi_device_data *data,
>         int ret, i;
>
>         ret = acpi_data_get_property(data, name, ACPI_TYPE_PACKAGE, &prop);
> -       if (ret)
> +       if (ret && obj) {

It changes semantics and requires obj to be non-NULL.

Should be
if (ret) {
  if (obj)
    *obj = NULL;
  return ret;
}

> +               *obj = NULL;
>                 return ret;
> +       }
>
>         if (type != ACPI_TYPE_ANY) {
>                 /* Check that all elements are of correct type. */
> --
> 2.26.0
>


-- 
With Best Regards,
Andy Shevchenko