2022-11-25 08:30:11

by Jani Nikula

Subject: Re: [PATCH] drm/i915/bios: fix a memory leak in generate_lfp_data_ptrs

On Fri, 25 Nov 2022, Xia Fukun <[email protected]> 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 <[email protected]>

Reviewed-by: Jani Nikula <[email protected]>

> ---
> 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

2022-11-29 10:23:54

by Jani Nikula

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

On Fri, 25 Nov 2022, Jani Nikula <[email protected]> wrote:
> On Fri, 25 Nov 2022, Xia Fukun <[email protected]> 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 <[email protected]>
>
> Reviewed-by: Jani Nikula <[email protected]>

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