amdgpf: BUG: NULL pointer dereference and memory leak

[Koenig, Christian]

Am 30.07.19 um 11:14 schrieb zhoucm1:
>
>
> On 2019年07月30日 17:04, Koenig, Christian wrote:
>> Am 30.07.19 um 10:47 schrieb 亿一:
>>> Hi  alll,
>>>            While analyzing the source code, I notice that function
>>> amdgpu_cs_process_fence_dep() may exist NULL pointer dereference and
>>> memory leak in the following code fragments:
>>>
>>>
>>> fence = amdgpu_ctx_get_fence(ctx, entity,
>>>       deps[i].handle);
>>>
>>> if (chunk->chunk_id == AMDGPU_CHUNK_ID_SCHEDULED_DEPENDENCIES) {
>>>           struct drm_sched_fence *s_fence = to_drm_sched_fence(fence);
>>>           struct dma_fence *old = fence;
>>>
>>>           fence = dma_fence_get(&s_fence->scheduled);
>>>           dma_fence_put(old);
>>> }
>>>
>>> if (IS_ERR(fence)) {
>>>            r = PTR_ERR(fence);
>>>            amdgpu_ctx_put(ctx);
>>>            return r;
>>>     } else if (fence) {
>>>             r = amdgpu_sync_fence(p->adev, &p->job->sync, fence,
>>>                                                    true);
>>>             dma_fence_put(fence);
>>>              amdgpu_ctx_put(ctx);
>>>              if (r)
>>>              return r;
>>>              }
>>>
>>> function amdgpu_ctx_get_fence may return NULL pointer,  which will
>>> cause NULL pointer dereference. What's more,  IS_ERR() would not
>>> return true when pointer is NULL,  which will cause the ctx reference
>>> leaked.
>> That handling is actually correct.
>>
>> The problem is the "if (chunk->chunk_id ==
>> AMDGPU_CHUNK_ID_SCHEDULED_DEPENDENCIES)" stuff above.
>>
>> That comes to early and needs to be moved below checking the fence for
>> errors. Going to send a fix for this to the mailing list in a minute.
> Lin Yi is right I think, we leaked ctx reference when fence is NULL.

Indeed, but what I meant was the a NULL fence here is not an error.

Just send out a patch to fix that stuff up, please review.

Christian.

>
> -David
>>
>> Thanks for the notice,
>> Christian.
>>
>>> But I don't know how to fix it, so report it to you all.
>>>
>>> Best Regards.
>>> Lin Yi.
>