igb: Fix igb_down hung on surprise removal

In the Linux kernel, the following vulnerability has been resolved:

igb: Fix igb_down hung on surprise removal

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.