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

["Khatri, Sunil" <sukhatri@xxxxxxx>]

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@xxxxxxx>
> > ---
> >   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 ?
>
> 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