On Wed, 6 Nov 2024 18:58:06 +0000
Liviu Dudau <liviu.dudau@xxxxxxx> wrote:
> Similar to cac075706f29 ("drm/panthor: Fix race when converting
> group handle to group object") we need to use the XArray's internal
> locking when retrieving a vm pointer from there.
>
> v2: Removed part of the patch that was trying to protect fetching
> the heap pointer from XArray, as that operation is protected by
> the @pool->lock.
>
> Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
> Reported-by: Jann Horn <jannh@xxxxxxxxxx>
> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> Cc: Steven Price <steven.price@xxxxxxx>
> Signed-off-by: Liviu Dudau <liviu.dudau@xxxxxxx>
> ---
> drivers/gpu/drm/panthor/panthor_mmu.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 8ca85526491e6..46b84a557d9cc 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1580,7 +1580,9 @@ panthor_vm_pool_get_vm(struct panthor_vm_pool *pool, u32 handle)
> {
> struct panthor_vm *vm;
>
> + xa_lock(&pool->xa);
> vm = panthor_vm_get(xa_load(&pool->xa, handle));
> + xa_unlock(&pool->xa);
>
> return vm;
> }
