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From:   Won Chung <wonchung@google.com>
Date:   Wed, 30 Mar 2022 14:15:40 -0700
Message-ID: <CAOvb9yivq8mEQCqKf0VynuEcAPo3-ZZ6YHyrH+vbwoJ0osY+JQ@mail.gmail.com>
Subject: Re: [PATCH v2] sound/hda: Add NULL check to component match callback function
To:     Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Cc:     Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Benson Leung <bleung@google.com>,
        Prashant Malani <pmalani@google.com>,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
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On Wed, Mar 30, 2022 at 1:55 PM Won Chung <wonchung@google.com> wrote:
>
> Component match callback function needs to check if expected data is
> passed to it. Without this check, it can cause a NULL pointer
> dereference when another driver registers a component before i915
> drivers have their component master fully bind.
>
> Fixes: 7b882fe3e3e8b ("ALSA: hda - handle multiple i915 device instances")
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Signed-off-by: Won Chung <wonchung@google.com>
> ---
> - Add "Fixes" tag
> - Send to stable@vger.kernel.org
>
>  sound/hda/hdac_i915.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c
> index efe810af28c5..958b0975fa40 100644
> --- a/sound/hda/hdac_i915.c
> +++ b/sound/hda/hdac_i915.c
> @@ -102,13 +102,13 @@ static int i915_component_master_match(struct device *dev, int subcomponent,
>         struct pci_dev *hdac_pci, *i915_pci;
>         struct hdac_bus *bus = data;
>
> -       if (!dev_is_pci(dev))
> +       if (!dev_is_pci(dev) || !bus)
>                 return 0;
>
>         hdac_pci = to_pci_dev(bus->dev);
>         i915_pci = to_pci_dev(dev);
>
> -       if (!strcmp(dev->driver->name, "i915") &&
> +       if (dev->driver && !strcmp(dev->driver->name, "i915") &&
>             subcomponent == I915_COMPONENT_AUDIO &&
>             connectivity_check(i915_pci, hdac_pci))
>                 return 1;
> --
> 2.35.1.1021.g381101b075-goog
>

Hi,

I am resending this patch to correct email accounts.
Sorry for confusion.

Thanks,
Won