Re: [PATCH] drm/buddy: release free_trees array on buddy mm teardown

[Matthew Auld <matthew.auld@intel.com>]

On 20/11/2025 09:30, Michał Grzelak wrote:
> During initialization of DRM buddy memory manager at drm_buddy_init,
> mm->free_trees array is allocated for both clear and dirty RB trees.
> During cleanup happening at drm_buddy_fini it is never freed, leading to
> following memory leaks observed on xe module load & unload cycles:
> 
>      kmemleak_alloc+0x4a/0x90
>      __kmalloc_cache_noprof+0x488/0x800
>      drm_buddy_init+0xc2/0x330 [drm_buddy]
>      __xe_ttm_vram_mgr_init+0xc3/0x190 [xe]
>      xe_ttm_stolen_mgr_init+0xf5/0x9d0 [xe]
>      xe_device_probe+0x326/0x9e0 [xe]
>      xe_pci_probe+0x39a/0x610 [xe]
>      local_pci_probe+0x47/0xb0
>      pci_device_probe+0xf3/0x260
>      really_probe+0xf1/0x3c0
>      __driver_probe_device+0x8c/0x180
>      driver_probe_device+0x24/0xd0
>      __driver_attach+0x10f/0x220
>      bus_for_each_dev+0x7f/0xe0
>      driver_attach+0x1e/0x30
>      bus_add_driver+0x151/0x290
> 
> Deallocate array for free trees when cleaning up buddy memory manager
> in the same way as if going through out_free_tree label.
> 
> Fixes: d4cd665c ("drm/buddy: Separate clear and dirty free block trees")
> Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

Reviewed-by: Matthew Auld <matthew.auld@intel.com>

> ---
>   drivers/gpu/drm/drm_buddy.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> index 2f279b46bd2c..8308116058cc 100644
> --- a/drivers/gpu/drm/drm_buddy.c
> +++ b/drivers/gpu/drm/drm_buddy.c
> @@ -420,6 +420,7 @@ void drm_buddy_fini(struct drm_buddy *mm)
>   
>   	for_each_free_tree(i)
>   		kfree(mm->free_trees[i]);
> +	kfree(mm->free_trees);
>   	kfree(mm->roots);
>   }
>   EXPORT_SYMBOL(drm_buddy_fini);