Re: [PATCH] mlxsw: pci: drain EQ tasklet during teardown

[Ido Schimmel <idosch@nvidia.com>]

On Sun, Oct 18, 2026 at 12:06:53PM +0800, Jiale Yao wrote:
> The EQ interrupt handler only schedules a tasklet. free_irq() prevents
> another interrupt handler from running, but it does not drain a tasklet
> that was queued before the IRQ was released.
> 
> The pending tasklet can access the EQ DMA buffer and queue array after
> mlxsw_pci_aqs_fini() releases them. Kill it after freeing the IRQ and
> before tearing down the asynchronous queues.
> 
> Fixes: eda6500a987a ("mlxsw: Add PCI bus implementation")
> Signed-off-by: Jiale Yao <yaojiale02@163.com>
> ---
>  drivers/net/ethernet/mellanox/mlxsw/pci.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
> index bfe3268dfdc1..ba66142ae333 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
> @@ -2085,8 +2085,11 @@ static int mlxsw_pci_init(void *bus_priv, struct mlxsw_core *mlxsw_core,
>  static void mlxsw_pci_fini(void *bus_priv)
>  {
>  	struct mlxsw_pci *mlxsw_pci = bus_priv;
> +	struct mlxsw_pci_queue *q;
>  
>  	free_irq(pci_irq_vector(mlxsw_pci->pdev, 0), mlxsw_pci);
> +	q = mlxsw_pci_eq_get(mlxsw_pci);
> +	tasklet_kill(&q->u.eq.tasklet);
>  	mlxsw_pci_aqs_fini(mlxsw_pci);
>  	mlxsw_pci_napi_devs_fini(mlxsw_pci);
>  	mlxsw_pci_fw_area_fini(mlxsw_pci);

Petr already looked into this [1]. Petr, please send your version when
net-next opens for 7.5.

[1] https://lore.kernel.org/netdev/875x2788ac.fsf@nvidia.com/