Re: [PATCH 5/7] drm/xe: Correct migration VM teardown order

[Matthew Brost <matthew.brost@intel.com>]

On Mon, Oct 20, 2025 at 09:45:27PM +0000, Stuart Summers wrote:
> Adjust the sequence of the migration teardown to match what
> is happening in the init() function.
> 
> v2: Take a reference to the migrate queue before put (Matt)
> 

You need to store the VM on the stack, not the queue;

> Signed-off-by: Stuart Summers <stuart.summers@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_migrate.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index 7345a5b65169..ae42917918e5 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -91,17 +91,18 @@ struct xe_migrate {
>  static void xe_migrate_fini(void *arg)
>  {
>  	struct xe_migrate *m = arg;
> +	struct xe_exec_queue *q = m->q;
>  
> -	xe_vm_lock(m->q->vm, false);
> +	xe_vm_lock(q->vm, false);
>  	xe_bo_unpin(m->pt_bo);
> -	xe_vm_unlock(m->q->vm);
> +	xe_vm_unlock(q->vm);
>  
>  	dma_fence_put(m->fence);
>  	xe_bo_put(m->pt_bo);
>  	drm_suballoc_manager_fini(&m->vm_update_sa);
>  	mutex_destroy(&m->job_mutex);
> -	xe_vm_close_and_put(m->q->vm);
> -	xe_exec_queue_put(m->q);
> +	xe_exec_queue_put(q);

^^^ This can destroy the 'q'.

> +	xe_vm_close_and_put(q->vm);

^^^ Now 'q->' can dereference invalid memory.

Matt

>  }
>  
>  static u64 xe_migrate_vm_addr(u64 slot, u32 level)
> -- 
> 2.34.1
>