Re: [PATCH] amdkfd: allow profiler process reenter

I suspect this won't work correctly. If the profiler locks the device 
multiple times, it probably also unlocks it multiple times. But I see no 
reference counting being done, so this may result in a situation where 
user mode locks twice, and unlocks once. Now it's lost the lock but it 
was still expecting to have it from the first lock operation.

I suspect that this is a user mode bug, and KFD is working as expected.

Regards,
   Felix

On 2026-08-12 03:14, Zhu, Lingshan wrote:
> AMD General
>
> Gentle Ping.
>
> Thanks
> Lingshan
>
> -----Original Message-----
> From: Zhu, Lingshan <[email protected]>
> Sent: Thursday, August 6, 2026 4:43 PM
> To: Deucher, Alexander <[email protected]>; Koenig, Christian <[email protected]>; Kuehling, Felix <[email protected]>
> Cc: Huang, Ray <[email protected]>; [email protected]; Zhu, Lingshan <[email protected]>
> Subject: [PATCH] amdkfd: allow profiler process reenter
>
> profile_lock_device() currently returns -EALREADY when the current profiler process requests to lock the device again. However any negtive values here are treated as failure, so this causes rejecting a profiler operation even though the caller still owns the device locking.
>
> This commit fixes this problem by returning 0 when the current profiler process locking the device again.
>
> This commit also changes profile_lock_device() to return an int value other than uint32_t, because it returns negative number when fail.
>
> Signed-off-by: Zhu Lingshan <[email protected]>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 309510e23315..9acd5c91e51c 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -3329,8 +3329,8 @@ static int kfd_ioctl_create_process(struct file *filep, struct kfd_process *p, v
>          return 0;
>   }
>
> -static inline uint32_t profile_lock_device(struct kfd_process *p,
> -                                          uint32_t gpu_id, uint32_t op)
> +static inline int profile_lock_device(struct kfd_process *p,
> +                                     uint32_t gpu_id, uint32_t op)
>   {
>          struct kfd_process_device *pdd;
>          struct kfd_dev *kfd;
> @@ -3365,7 +3365,7 @@ static inline uint32_t profile_lock_device(struct kfd_process *p,
>                          }
>                          return status;
>                  } else if (kfd->profiler_process == p) {
> -                       status = -EALREADY;
> +                       status = 0;
>                  } else {
>                          status = -EBUSY;
>                  }
> --
> 2.53.0
>