Re: [Intel-gfx] [PATCH] drm/i915/bios: fix a memory leak in generate_lfp_data_ptrs

[Jani Nikula]

On Fri, 25 Nov 2022, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Fri, 25 Nov 2022, Xia Fukun <xiafukun@xxxxxxxxxx> wrote:
>> When (size != 0 || ptrs->lvds_ entries != 3), the program tries to
>> free() the ptrs. However, the ptrs is not created by calling kzmalloc(),
>> but is obtained by pointer offset operation.
>> This may lead to memory leaks or undefined behavior.
>
> Yeah probably worse things will happen than just leak.
>
>>
>> Fix this by replacing the arguments of kfree() with ptrs_block.
>>
>> Fixes: a87d0a847607 ("drm/i915/bios: Generate LFP data table pointers if the VBT lacks them")
>> Signed-off-by: Xia Fukun <xiafukun@xxxxxxxxxx>
>
> Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>

And pushed to drm-intel-next, thanks for the patch.

BR,
Jani.

>
>> ---
>>  drivers/gpu/drm/i915/display/intel_bios.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
>> index 28bdb936cd1f..edbdb949b6ce 100644
>> --- a/drivers/gpu/drm/i915/display/intel_bios.c
>> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
>> @@ -414,7 +414,7 @@ static void *generate_lfp_data_ptrs(struct drm_i915_private *i915,
>>  		ptrs->lvds_entries++;
>>  
>>  	if (size != 0 || ptrs->lvds_entries != 3) {
>> -		kfree(ptrs);
>> +		kfree(ptrs_block);
>>  		return NULL;
>>  	}

-- 
Jani Nikula, Intel Open Source Graphics Center