Re: [PATCH] drm/amdgpu: Fix validating flush_gpu_tlb_pasid()

["Christian König" <christian.koenig@amd.com>]

On 1/18/26 13:57, Timur Kristóf wrote:
> When a function holds a lock and we return without unlocking it,
> it deadlocks the kernel. We should always unlock before returning.
> 
> This commit fixes suspend/resume on SI.
> Tested on two Tahiti GPUs: FirePro W9000 and R9 280X.
> 
> Fixes: bc2dea30038a ("drm/amdgpu: validate the flush_gpu_tlb_pasid()")
> Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> index 0e67fa4338ff..4fa24be1bf45 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> @@ -769,7 +769,7 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
>  	struct amdgpu_ring *ring = &adev->gfx.kiq[inst].ring;
>  	struct amdgpu_kiq *kiq = &adev->gfx.kiq[inst];
>  	unsigned int ndw;
> -	int r, cnt = 0;
> +	int r = 0, cnt = 0;

Please don't initialize return values in the declaration, that is usually considered bad coding style.

>  	uint32_t seq;
>  
>  	/*
> @@ -782,7 +782,7 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
>  	if (!adev->gmc.flush_pasid_uses_kiq || !ring->sched.ready) {
>  
>  		if (!adev->gmc.gmc_funcs->flush_gpu_tlb_pasid)
> -			return 0;
> +			goto error_unlock_reset;

Ah, yes good catch!

With the change to r initialization dropped: Reviewed-by: Christian König <christian.koenig@amd.com>

Regards,
Christian.

>  
>  		if (adev->gmc.flush_tlb_needs_extra_type_2)
>  			adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
> @@ -797,7 +797,6 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
>  		adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
>  							 flush_type, all_hub,
>  							 inst);
> -		r = 0;
>  	} else {
>  		/* 2 dwords flush + 8 dwords fence */
>  		ndw = kiq->pmf->invalidate_tlbs_size + 8;