From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: alsa-devel@alsa-project.org, Takashi Iwai <tiwai@suse.de>,
linux-kernel@vger.kernel.org, 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
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [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
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2016-02-16 22:08 UTC|newest]
Thread overview: 48+ 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 14:47 ` Arnd Bergmann
2016-02-16 14:47 ` Arnd Bergmann
2016-02-16 15:49 ` Takashi Iwai
2016-02-16 15:49 ` Takashi Iwai
2016-02-16 15:49 ` Takashi Iwai
2016-02-16 16:09 ` Arnd Bergmann
2016-02-16 16:09 ` Arnd Bergmann
2016-02-16 16:09 ` Arnd Bergmann
2016-02-16 16:18 ` Takashi Iwai
2016-02-16 16:18 ` Takashi Iwai
2016-02-16 16:38 ` Mark Brown
2016-02-16 16:38 ` Mark Brown
2016-02-16 16:43 ` Takashi Iwai
2016-02-16 16:43 ` Takashi Iwai
2016-02-16 16:59 ` Arnd Bergmann
2016-02-16 16:59 ` Arnd Bergmann
2016-02-16 16:59 ` Arnd Bergmann
2016-02-16 17:09 ` Arnd Bergmann
2016-02-16 17:09 ` Arnd Bergmann
2016-02-16 17:09 ` Arnd Bergmann
2016-02-16 17:10 ` Takashi Iwai
2016-02-16 17:10 ` Takashi Iwai
2016-02-16 17:26 ` Arnd Bergmann
2016-02-16 17:26 ` Arnd Bergmann
2016-02-16 17:26 ` Arnd Bergmann
2016-02-16 22:08 ` Arnd Bergmann [this message]
2016-02-16 22:08 ` Arnd Bergmann
2016-02-16 22:08 ` Arnd Bergmann
2016-02-17 9:03 ` Takashi Iwai
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 9:24 ` kbuild test robot
2016-02-17 9:35 ` [PATCH] sound: hdmi: avoid dereferencing uninitialized 'jack' pointer Takashi Iwai
2016-02-17 9:35 ` Takashi Iwai
2016-02-17 9:35 ` Takashi Iwai
2016-02-17 9:40 ` Arnd Bergmann
2016-02-17 9:40 ` Arnd Bergmann
2016-02-17 9:40 ` Arnd Bergmann
2016-02-24 16:18 ` Arnd Bergmann
2016-02-24 16:18 ` Arnd Bergmann
2016-02-24 16:18 ` Arnd Bergmann
2016-02-24 16:25 ` Takashi Iwai
2016-02-24 16:25 ` Takashi Iwai
2016-02-24 16:39 ` Arnd Bergmann
2016-02-24 16:39 ` Arnd Bergmann
2016-02-24 16:39 ` Arnd Bergmann
2016-02-26 2:46 ` Applied "ASoC: trace: fix printing jack name" to the asoc tree Mark Brown
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