Re: [PATCH net-next] igb: Fix igb_down hung on surprise removal

[Simon Horman <simon.horman@corigine.com>]

On Tue, Jun 20, 2023 at 10:47:32AM -0700, Tony Nguyen wrote:
> From: Ying Hsu <yinghsu@chromium.org>
> 
> In a setup where a Thunderbolt hub connects to Ethernet and a display
> through USB Type-C, users may experience a hung task timeout when they
> remove the cable between the PC and the Thunderbolt hub.
> This is because the igb_down function is called multiple times when
> the Thunderbolt hub is unplugged. For example, the igb_io_error_detected
> triggers the first call, and the igb_remove triggers the second call.
> The second call to igb_down will block at napi_synchronize.
> Here's the call trace:
>     __schedule+0x3b0/0xddb
>     ? __mod_timer+0x164/0x5d3
>     schedule+0x44/0xa8
>     schedule_timeout+0xb2/0x2a4
>     ? run_local_timers+0x4e/0x4e
>     msleep+0x31/0x38
>     igb_down+0x12c/0x22a [igb 6615058754948bfde0bf01429257eb59f13030d4]
>     __igb_close+0x6f/0x9c [igb 6615058754948bfde0bf01429257eb59f13030d4]
>     igb_close+0x23/0x2b [igb 6615058754948bfde0bf01429257eb59f13030d4]
>     __dev_close_many+0x95/0xec
>     dev_close_many+0x6e/0x103
>     unregister_netdevice_many+0x105/0x5b1
>     unregister_netdevice_queue+0xc2/0x10d
>     unregister_netdev+0x1c/0x23
>     igb_remove+0xa7/0x11c [igb 6615058754948bfde0bf01429257eb59f13030d4]
>     pci_device_remove+0x3f/0x9c
>     device_release_driver_internal+0xfe/0x1b4
>     pci_stop_bus_device+0x5b/0x7f
>     pci_stop_bus_device+0x30/0x7f
>     pci_stop_bus_device+0x30/0x7f
>     pci_stop_and_remove_bus_device+0x12/0x19
>     pciehp_unconfigure_device+0x76/0xe9
>     pciehp_disable_slot+0x6e/0x131
>     pciehp_handle_presence_or_link_change+0x7a/0x3f7
>     pciehp_ist+0xbe/0x194
>     irq_thread_fn+0x22/0x4d
>     ? irq_thread+0x1fd/0x1fd
>     irq_thread+0x17b/0x1fd
>     ? irq_forced_thread_fn+0x5f/0x5f
>     kthread+0x142/0x153
>     ? __irq_get_irqchip_state+0x46/0x46
>     ? kthread_associate_blkcg+0x71/0x71
>     ret_from_fork+0x1f/0x30
> 
> In this case, igb_io_error_detected detaches the network interface
> and requests a PCIE slot reset, however, the PCIE reset callback is
> not being invoked and thus the Ethernet connection breaks down.
> As the PCIE error in this case is a non-fatal one, requesting a
> slot reset can be avoided.
> This patch fixes the task hung issue and preserves Ethernet
> connection by ignoring non-fatal PCIE errors.
> 
> Signed-off-by: Ying Hsu <yinghsu@chromium.org>
> Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
> ---
>  drivers/net/ethernet/intel/igb/igb_main.c | 5 +++++
>  1 file changed, 5 insertions(+)

Reviewed-by: Simon Horman <simon.horman@corigine.com>