Re: [PATCH] drm/amd/amdgpu/amdgpu_ttm: Handle return NULL error from ioremap_nocache

From: Alex Deucher
Date: Tue Jan 24 2017 - 17:12:01 EST


On Tue, Jan 24, 2017 at 4:55 AM, Christian KÃnig
<deathsimple@xxxxxxxxxxx> wrote:
> Am 24.01.2017 um 10:25 schrieb Arvind Yadav:
>>
>> Here, If ioremap_nocache will fail. It will return NULL.
>> Kernel can run into a NULL-pointer dereference.
>> This error check will avoid NULL pointer dereference.
>>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
>
>
> I'm not 100% sure if ioremap_nocache() can actually return NULL on platforms
> where this matters, but if that's the case the patch looks reasonable on
> first glance.
>
> So it is Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>.
>

Applied this and the radeon patch.

Alex

> Regards,
> Christian.
>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 8e35c1f..610c88f 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -552,6 +552,8 @@ static int amdgpu_ttm_io_mem_reserve(struct
>> ttm_bo_device *bdev, struct ttm_mem_
>> mem->bus.addr =
>> ioremap_nocache(mem->bus.base +
>> mem->bus.offset,
>> mem->bus.size);
>> + if (!mem->bus.addr)
>> + return -ENOMEM;
>> /*
>> * Alpha: Use just the bus offset plus
>
>
>
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