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

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski [off-list ref]:

On Tue, 20 Jun 2023 10:47:32 -0700 you wrote:

From: Ying Hsu <redacted>

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

[...]

Here is the summary with links:
  - [net-next] igb: Fix igb_down hung on surprise removal
    https://git.kernel.org/netdev/net-next/c/004d25060c78

You are awesome, thank you!
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