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

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

[Jiale Yao]

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);
-- 
2.34.1

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

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

 - What hardware the change was tested on. For driver fixes please
   mention the device (and if relevant firmware version) used for
   testing, or say that the change was not tested on real hardware.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

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

[Ido Schimmel]

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/