Re: [PATCH] drm/i915/audio: fix check for av_enc_map overflow

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 15 Feb 2018, Mika Kahola <mika.kahola@intel.com> wrote:
> On Wed, 2018-02-14 at 19:38 +0200, Jani Nikula wrote:
>> Turns out -1 >= ARRAY_SIZE() is always true. Move the bounds check
>> where
>> we know pipe >= 0 and next to the array indexing where it makes most
>> sense.
>> 
>> Fixes: 9965db26ac05 ("drm/i915: Check for fused or unused pipes")
>> Fixes: 0b7029b7e43f ("drm/i915: Check for fused or unused pipes")
>> Cc: <stable@vger.kernel.org> # v4.10+
>> Cc: Mika Kahola <mika.kahola@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>> Cc: intel-gfx@lists.freedesktop.org
>
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>

Pushed to dinq, thanks for the reviews.

BR,
Jani.

>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_audio.c | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_audio.c
>> b/drivers/gpu/drm/i915/intel_audio.c
>> index ff455c724775..709d6ca68074 100644
>> --- a/drivers/gpu/drm/i915/intel_audio.c
>> +++ b/drivers/gpu/drm/i915/intel_audio.c
>> @@ -779,11 +779,11 @@ static struct intel_encoder
>> *get_saved_enc(struct drm_i915_private *dev_priv,
>>  {
>>  	struct intel_encoder *encoder;
>>  
>> -	if (WARN_ON(pipe >= ARRAY_SIZE(dev_priv->av_enc_map)))
>> -		return NULL;
>> -
>>  	/* MST */
>>  	if (pipe >= 0) {
>> +		if (WARN_ON(pipe >= ARRAY_SIZE(dev_priv-
>> >av_enc_map)))
>> +			return NULL;
>> +
>>  		encoder = dev_priv->av_enc_map[pipe];
>>  		/*
>>  		 * when bootup, audio driver may not know it is

-- 
Jani Nikula, Intel Open Source Technology Center