linux-kernel - Re: [PATCH] drm/amdgpu: add vm fault information to devcoredump

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Message-ID: <3ff55fef-efd7-4de6-b81f-a5a57021e4bb@amd.com>
Date: Thu, 7 Mar 2024 18:13:10 +0530
From: "Khatri, Sunil" <sukhatri@....com>
To: Christian König <christian.koenig@....com>,
 Sunil Khatri <sunil.khatri@....com>, Alex Deucher
 <alexander.deucher@....com>, Shashank Sharma <shashank.sharma@....com>
Cc: amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, Mukul Joshi <mukul.joshi@....com>,
 Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@....com>
Subject: Re: [PATCH] drm/amdgpu: add vm fault information to devcoredump


On 3/7/2024 6:10 PM, Christian König wrote:
> Am 07.03.24 um 09:37 schrieb Khatri, Sunil:
>>
>> On 3/7/2024 1:47 PM, Christian König wrote:
>>> Am 06.03.24 um 19:19 schrieb Sunil Khatri:
>>>> Add page fault information to the devcoredump.
>>>>
>>>> Output of devcoredump:
>>>> **** AMDGPU Device Coredump ****
>>>> version: 1
>>>> kernel: 6.7.0-amd-staging-drm-next
>>>> module: amdgpu
>>>> time: 29.725011811
>>>> process_name: soft_recovery_p PID: 1720
>>>>
>>>> Ring timed out details
>>>> IP Type: 0 Ring Name: gfx_0.0.0
>>>>
>>>> [gfxhub] Page fault observed for GPU family:143
>>>> Faulty page starting at address 0x0000000000000000
>>>> Protection fault status register:0x301031
>>>>
>>>> VRAM is lost due to GPU reset!
>>>>
>>>> Signed-off-by: Sunil Khatri <sunil.khatri@....com>
>>>> ---
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c | 15 ++++++++++++++-
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h |  1 +
>>>>   2 files changed, 15 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c 
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
>>>> index 147100c27c2d..d7fea6cdf2f9 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
>>>> @@ -203,8 +203,20 @@ amdgpu_devcoredump_read(char *buffer, loff_t 
>>>> offset, size_t count,
>>>>                  coredump->ring->name);
>>>>       }
>>>>   +    if (coredump->fault_info.status) {
>>>> +        struct amdgpu_vm_fault_info *fault_info = 
>>>> &coredump->fault_info;
>>>> +
>>>> +        drm_printf(&p, "\n[%s] Page fault observed for GPU 
>>>> family:%d\n",
>>>> +               fault_info->vmhub ? "mmhub" : "gfxhub",
>>>> +               coredump->adev->family);
>>>> +        drm_printf(&p, "Faulty page starting at address 0x%016llx\n",
>>>> +               fault_info->addr);
>>>> +        drm_printf(&p, "Protection fault status register:0x%x\n",
>>>> +               fault_info->status);
>>>> +    }
>>>> +
>>>>       if (coredump->reset_vram_lost)
>>>> -        drm_printf(&p, "VRAM is lost due to GPU reset!\n");
>>>> +        drm_printf(&p, "\nVRAM is lost due to GPU reset!\n");
>>>>       if (coredump->adev->reset_info.num_regs) {
>>>>           drm_printf(&p, "AMDGPU register dumps:\nOffset:     
>>>> Value:\n");
>>>>   @@ -253,6 +265,7 @@ void amdgpu_coredump(struct amdgpu_device 
>>>> *adev, bool vram_lost,
>>>>       if (job) {
>>>>           s_job = &job->base;
>>>>           coredump->ring = to_amdgpu_ring(s_job->sched);
>>>> +        coredump->fault_info = job->vm->fault_info;
>>>
>>> That's illegal. The VM pointer might already be stale at this point.
>>>
>>> I think you need to add the fault info of the last fault globally in 
>>> the VRAM manager or move this to the process info Shashank is 
>>> working on.
>>> Are you saying that during the reset or otherwise a vm which is part 
>>> of this job could have been freed  and we might have a NULL 
>>> dereference or invalid reference? Till now based on the resets and 
>>> pagefaults that i have created till now using the same app which we 
>>> are using for IH overflow i am able to get the valid vm only.
>>>
>>> Assuming  amdgpu_vm is freed for this job or stale, are you 
>>> suggesting to update this information in adev-> vm_manager along 
>>> with existing per vm fault_info or only in vm_manager ?
>
> Good question. having it both in the VM as well as the VM manager 
> sounds like the simplest option for now.

Let me update the patch then with information in VM manager.

Regards
Sunil

>
> Regards,
> Christian.
>
>>>
>>> Regards,
>>> Christian.
>>>
>>>>       }
>>>>         coredump->adev = adev;
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h 
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>>> index 60522963aaca..3197955264f9 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.h
>>>> @@ -98,6 +98,7 @@ struct amdgpu_coredump_info {
>>>>       struct timespec64               reset_time;
>>>>       bool                            reset_vram_lost;
>>>>       struct amdgpu_ring            *ring;
>>>> +    struct amdgpu_vm_fault_info    fault_info;
>>>>   };
>>>>   #endif
>>>
>