Re: [PATCH] drm/msm: adreno: fix deferencing ifpc_reglist when not declared

[Akhil P Oommen <akhilpo@oss.qualcomm.com>]

On 11/18/2025 1:05 PM, Akhil P Oommen wrote:
> On 11/17/2025 8:21 PM, Neil Armstrong wrote:
>> On plaforms with an a7xx GPU not supporting IFPC, the ifpc_reglist
>> if still deferenced in a7xx_patch_pwrup_reglist() which causes
>> a kernel crash:
>> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
>> ...
>> pc : a6xx_hw_init+0x155c/0x1e4c [msm]
>> lr : a6xx_hw_init+0x9a8/0x1e4c [msm]
>> ...
>> Call trace:
>>   a6xx_hw_init+0x155c/0x1e4c [msm] (P)
>>   msm_gpu_hw_init+0x58/0x88 [msm]
>>   adreno_load_gpu+0x94/0x1fc [msm]
>>   msm_open+0xe4/0xf4 [msm]
>>   drm_file_alloc+0x1a0/0x2e4 [drm]
>>   drm_client_init+0x7c/0x104 [drm]
>>   drm_fbdev_client_setup+0x94/0xcf0 [drm_client_lib]
>>   drm_client_setup+0xb4/0xd8 [drm_client_lib]
>>   msm_drm_kms_post_init+0x2c/0x3c [msm]
>>   msm_drm_init+0x1a4/0x228 [msm]
>>   msm_drm_bind+0x30/0x3c [msm]
>> ...
>>
>> Check the validity of ifpc_reglist before deferencing the table
>> to setup the register values.
>>
>> Fixes: a6a0157cc68e ("drm/msm/a6xx: Enable IFPC on Adreno X1-85")
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> 
> Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
> 
> Thanks for fixing this. Chia reported this issue a couple of weeks back.
> Probably, we can add his S-b tag.

Sorry, I meant R-b tag.

> https://lore.kernel.org/lkml/CAPaKu7QvBZmx0b8SDBY1H3u-Em+0py0BrGkmrfGUXkx1uQrg3A@mail.gmail.com/
> 
> -Akhil
>