Re: [Intel-wired-lan] [PATCH v2] e1000e: free IRQ regardless of __E1000_DOWN

From: Neftin, Sasha
Date: Thu Nov 10 2016 - 01:19:47 EST


On 11/9/2016 11:41 PM, Tyler Baicar wrote:
> Move IRQ free code so that it will happen regardless of the
> __E1000_DOWN bit. Currently the e1000e driver only releases its IRQ
> if the __E1000_DOWN bit is cleared. This is not sufficient because
> it is possible for __E1000_DOWN to be set without releasing the IRQ.
> In such a situation, we will hit a kernel bug later in e1000_remove
> because the IRQ still has action since it was never freed. A
> secondary bus reset can cause this case to happen.
>
> Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
> ---
> drivers/net/ethernet/intel/e1000e/netdev.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 7017281..36cfcb0 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -4679,12 +4679,13 @@ int e1000e_close(struct net_device *netdev)
>
> if (!test_bit(__E1000_DOWN, &adapter->state)) {
> e1000e_down(adapter, true);
> - e1000_free_irq(adapter);
>
> /* Link status message must follow this format */
> pr_info("%s NIC Link is Down\n", adapter->netdev->name);
> }
>
> + e1000_free_irq(adapter);
> +
> napi_disable(&adapter->napi);
>
> e1000e_free_tx_resources(adapter->tx_ring);
>
I would like not recommend insert this change. This change related
driver state machine, we afraid from lot of synchronization problem and
issues.
We need keep e1000_free_irq in loop and check for 'test_bit' ready.
Another point, does before execute secondary bus reset your SW back up
pcie configuration space as properly?

Sasha