linux-kernel - Re: [PATCH v2 5/6] drm/amdgpu: Log IBs and ring name at coredump

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Date:   Fri, 14 Jul 2023 09:57:39 +0200
From:   Christian König <ckoenig.leichtzumerken@...il.com>
To:     André Almeida <andrealmeid@...lia.com>,
        dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Cc:     pierre-eric.pelloux-prayer@....com,
        'Marek Olšák' <maraeo@...il.com>,
        Timur Kristóf <timur.kristof@...il.com>,
        michel.daenzer@...lbox.org,
        Samuel Pitoiset <samuel.pitoiset@...il.com>,
        kernel-dev@...lia.com, Bas Nieuwenhuizen <bas@...nieuwenhuizen.nl>,
        alexander.deucher@....com, christian.koenig@....com
Subject: Re: [PATCH v2 5/6] drm/amdgpu: Log IBs and ring name at coredump

Am 13.07.23 um 23:32 schrieb André Almeida:
> Log the IB addresses used by the hung job along with the stuck ring
> name. Note that due to nested IBs, the one that caused the reset itself
> may be in not listed address.
>
> Signed-off-by: André Almeida <andrealmeid@...lia.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  3 +++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 31 +++++++++++++++++++++-
>   2 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index e1cc83a89d46..cfeaf93934fd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1086,6 +1086,9 @@ struct amdgpu_coredump_info {
>   	struct amdgpu_task_info         reset_task_info;
>   	struct timespec64               reset_time;
>   	bool                            reset_vram_lost;
> +	u64				*ibs;
> +	u32				num_ibs;
> +	char				ring_name[16];
>   };
>   #endif
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 07546781b8b8..431ccc3d7857 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -5008,12 +5008,24 @@ static ssize_t amdgpu_devcoredump_read(char *buffer, loff_t offset,
>   				   coredump->adev->reset_dump_reg_value[i]);
>   	}
>   
> +	if (coredump->num_ibs) {
> +		drm_printf(&p, "IBs:\n");
> +		for (i = 0; i < coredump->num_ibs; i++)
> +			drm_printf(&p, "\t[%d] 0x%llx\n", i, coredump->ibs[i]);
> +	}
> +
> +	if (coredump->ring_name[0] != '\0')
> +		drm_printf(&p, "ring name: %s\n", coredump->ring_name);
> +
>   	return count - iter.remain;
>   }
>   
>   static void amdgpu_devcoredump_free(void *data)
>   {
> -	kfree(data);
> +	struct amdgpu_coredump_info *coredump = data;
> +
> +	kfree(coredump->ibs);
> +	kfree(coredump);
>   }
>   
>   static void amdgpu_coredump(struct amdgpu_device *adev, bool vram_lost,
> @@ -5021,6 +5033,8 @@ static void amdgpu_coredump(struct amdgpu_device *adev, bool vram_lost,
>   {
>   	struct amdgpu_coredump_info *coredump;
>   	struct drm_device *dev = adev_to_drm(adev);
> +	struct amdgpu_job *job = reset_context->job;
> +	int i;
>   
>   	coredump = kmalloc(sizeof(*coredump), GFP_NOWAIT);
>   
> @@ -5038,6 +5052,21 @@ static void amdgpu_coredump(struct amdgpu_device *adev, bool vram_lost,
>   
>   	coredump->adev = adev;
>   
> +	if (job && job->num_ibs) {

I really really really don't want any dependency of the core dump 
feature towards the job.

What we could do is to record the first executed IB VAs in the hw fence, 
but I'm not sure how useful this is in the first place.

We have some internal feature in progress to query the VA of the draw 
command which cause the waves currently executing in the SQ to be retrieved.

> +		struct amdgpu_ring *ring = to_amdgpu_ring(job->base.sched);
> +		u32 num_ibs = job->num_ibs;
> +
> +		coredump->ibs = kmalloc_array(num_ibs, sizeof(coredump->ibs), GFP_NOWAIT);

This can fail pretty easily.

Christian.

> +		if (coredump->ibs)
> +			coredump->num_ibs = num_ibs;
> +
> +		for (i = 0; i < coredump->num_ibs; i++)
> +			coredump->ibs[i] = job->ibs[i].gpu_addr;
> +
> +		if (ring)
> +			strncpy(coredump->ring_name, ring->name, 16);
> +	}
> +
>   	ktime_get_ts64(&coredump->reset_time);
>   
>   	dev_coredumpm(dev->dev, THIS_MODULE, coredump, 0, GFP_NOWAIT,