在 2018/11/23 21:30, Koenig, Christian 写道:
> Am 23.11.18 um 14:27 schrieb Zhou, David(ChunMing):
>> 在 2018/11/22 19:25, Christian König 写道:
>>> Am 22.11.18 um 07:56 schrieb Sharma, Deepak:
>>>> when returned fence is not valid mostly due to userspace ignored
>>>> previous error causes NULL pointer dereference.
>>> Again, this is clearly incorrect. The my other mails on the earlier
>>> patch.
>> Sorry for I didn't get your history, but looks from the patch itself, it
>> is still a valid patch, isn't it?
> No, the semantic of amdgpu_ctx_get_fence() is that we return NULL when
> the fence is already signaled.
>
> So this patch could totally break userspace because it changes the
> behavior when we try to sync to an already signaled fence.
Ah, I got your meaning, how about attached patch?
-David
>
> If that patch was applied then please revert it immediately.
>
> Christian.
>
>> -David
>>> If you have already pushed the patch then please revert.
>>>
>>> Christian.
>>>
>>>> Signed-off-by: Deepak Sharma <Deepak.Sharma@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>> index 024dfbd87f11..14166cd8a12f 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>>>> @@ -1403,6 +1403,8 @@ static struct dma_fence
>>>> *amdgpu_cs_get_fence(struct amdgpu_device *adev,
>>>> fence = amdgpu_ctx_get_fence(ctx, entity, user->seq_no);
>>>> amdgpu_ctx_put(ctx);
>>>> + if(!fence)
>>>> + return ERR_PTR(-EINVAL);
>>>> return fence;
>>>> }
From 3640a18c31e7b786129286615fcdf397e1142451 Mon Sep 17 00:00:00 2001
From: Chunming Zhou <david1.zhou@xxxxxxx>
Date: Fri, 23 Nov 2018 22:05:19 +0800
Subject: [PATCH] drm/amdgpu: fix signaled fence isn't handled
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Chunming Zhou <david1.zhou@xxxxxxx>
Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>
CC: Christian König <Christian.Koenig@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 3 +++
drivers/gpu/drm/drm_syncobj.c | 1 +
include/drm/drm_syncobj.h | 1 +
3 files changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 6a823b58b3b8..e960f9864e9f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1505,6 +1505,9 @@ int amdgpu_cs_fence_to_handle_ioctl(struct drm_device *dev, void *data,
if (IS_ERR(fence))
return PTR_ERR(fence);
+ /* that means fence was signaled */
+ if (!fence)
+ fence = drm_syncobj_get_stub_fence();
switch (info->in.what) {
case AMDGPU_FENCE_TO_HANDLE_GET_SYNCOBJ:
r = drm_syncobj_create(&syncobj, 0, fence);
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 5f2df10e51c3..e5621f80d501 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -97,6 +97,7 @@ struct dma_fence *drm_syncobj_get_stub_fence(void)
return dma_fence_get(&signaled_fence);
}
+EXPORT_SYMBOL(drm_syncobj_get_stub_fence);
/**
* drm_syncobj_find - lookup and reference a sync object.
* @file_private: drm file private pointer
diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
index 29244cbcd05e..93e9e9b159ab 100644
--- a/include/drm/drm_syncobj.h
+++ b/include/drm/drm_syncobj.h
@@ -147,5 +147,6 @@ int drm_syncobj_get_handle(struct drm_file *file_private,
int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd);
int drm_syncobj_search_fence(struct drm_syncobj *syncobj, u64 point, u64 flags,
struct dma_fence **fence);
+struct dma_fence *drm_syncobj_get_stub_fence(void);
#endif
--
2.17.1
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