[PATCH] drm/amdgpu: fix deadlock of reservation between cs and gpu reset v2

[Zhang, Jerry]

Nice catch!
Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com>

Regards,
Jerry (Junwei Zhang)

Linux Base Graphics
SRDC Software Development
_____________________________________


> -----Original Message-----
> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of
> Chunming Zhou
> Sent: Friday, April 28, 2017 10:46
> To: amd-gfx at lists.freedesktop.org
> Cc: Zhou, David(ChunMing)
> Subject: [PATCH] drm/amdgpu: fix deadlock of reservation between cs and gpu
> reset v2
> 
> the case could happen when gpu reset:
> 1. when gpu reset, cs can be continue until sw queue is full, then push job will
> wait with holding pd reservation.
> 2. gpu_reset routine will also need pd reservation to restore page table from
> their shadow.
> 3. cs is waiting for gpu_reset complete, but gpu reset is waiting for cs releases
> reservation.
> 
> v2: handle amdgpu_cs_submit error path.
> 
> Change-Id: I0f66d04b2bef3433035109623c8a5c5992c84202
> Signed-off-by: Chunming Zhou <David1.Zhou at amd.com>
> Reviewed-by: Christian König <christian.koenig at amd.com>
> Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com>
> Reviewed-by: Monk Liu <monk.liu at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 26168df..699f5fe 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1074,6 +1074,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser
> *p,
>  	cs->out.handle = amdgpu_ctx_add_fence(p->ctx, ring, p->fence);
>  	job->uf_sequence = cs->out.handle;
>  	amdgpu_job_free_resources(job);
> +	amdgpu_cs_parser_fini(p, 0, true);
> 
>  	trace_amdgpu_cs_ioctl(job);
>  	amd_sched_entity_push_job(&job->base);
> @@ -1129,7 +1130,10 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void
> *data, struct drm_file *filp)
>  		goto out;
> 
>  	r = amdgpu_cs_submit(&parser, cs);
> +	if (r)
> +		goto out;
> 
> +	return 0;
>  out:
>  	amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
>  	return r;
> --
> 1.9.1
> 
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