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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Takashi Iwai <tiwai@suse.de>,
	alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	Jaroslav Kysela <perex@perex.cz>, Mark Brown <broonie@kernel.org>,
	Han Lu <han.lu@intel.com>,
	Libin Yang <libin.yang@linux.intel.com>,
	Thierry Reding <treding@nvidia.com>,
	David Henningsson <david.henningsson@canonical.com>
Subject: Re: [PATCH] sound: hdmi: avoid dereferencing uninitialized 'jack' pointer
Date: Tue, 16 Feb 2016 23:08:13 +0100	[thread overview]
Message-ID: <3395859.dhsfOsmVIe@wuerfel> (raw)
In-Reply-To: <2706488.VpKveMVPGI@wuerfel>

On Tuesday 16 February 2016 18:26:09 Arnd Bergmann wrote:
> >                 return err;
> >         per_pin->acomp_jack = jack;
> > -       jack->private_data = per_pin;
> > -       jack->private_free = free_acomp_jack_priv;
> > +       if (jack) {
> > +               jack->private_data = per_pin;
> > +               jack->private_free = free_acomp_jack_priv;
> > +       }
> >         return 0;
> >  }
> > 
> Looks good to me.
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> 

Actually, on second thought, there is one notable downside
of this approach: 'jack' is guaranteed to be NULL here, so gcc
won't produce a warning if another driver makes the same mistake:

By default, we only get a warning for uses of uninitialized
variables, but not those that are known to be NULL. I think
some compiler warnings are able to warn about that too, but I
forgot the details.

	Arnd

  reply	other threads:[~2016-02-16 22:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-16 14:47 [PATCH] sound: hdmi: avoid dereferencing uninitialized 'jack' pointer Arnd Bergmann
2016-02-16 15:49 ` Takashi Iwai
2016-02-16 16:09   ` Arnd Bergmann
2016-02-16 16:18     ` Takashi Iwai
2016-02-16 16:38       ` Mark Brown
2016-02-16 16:43         ` Takashi Iwai
2016-02-16 16:59         ` Arnd Bergmann
2016-02-16 17:09           ` Arnd Bergmann
2016-02-16 17:10           ` Takashi Iwai
2016-02-16 17:26             ` Arnd Bergmann
2016-02-16 22:08               ` Arnd Bergmann [this message]
2016-02-17  9:03                 ` Takashi Iwai
2016-02-17  9:24                   ` [PATCH] ALSA: jack: Allow building the jack layer without input kbuild test robot
2016-02-17  9:35                   ` [PATCH] sound: hdmi: avoid dereferencing uninitialized 'jack' pointer Takashi Iwai
2016-02-17  9:40                     ` Arnd Bergmann
2016-02-24 16:18                     ` Arnd Bergmann
2016-02-24 16:25                       ` Takashi Iwai
2016-02-24 16:39                         ` Arnd Bergmann

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