RE: [Intel-wired-lan] [PATCH] igb: Fix igb_down hung on surprise removal

[Pucha, HimasekharX Reddy]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of Ying Hsu
> Sent: Thursday, May 18, 2023 12:57 PM
> To: netdev@xxxxxxxxxxxxxxx
> Cc: grundler@xxxxxxxxxxxx; intel-wired-lan@xxxxxxxxxxxxxxxx; Ying Hsu <yinghsu@xxxxxxxxxxxx>; Brandeburg, Jesse <jesse.brandeburg@xxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; Eric Dumazet <edumazet@xxxxxxxxxx>; Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>
> Subject: [Intel-wired-lan] [PATCH] 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.
>
> Signed-off-by: Ying Hsu <yinghsu@xxxxxxxxxxxx>
> ---
> This commit has been tested on a HP Elite Dragonfly Chromebook and a Caldigit TS3+ Thunderbolt hub. The Ethernet driver for the hub is igb. Non-fatal PCIE errors happen when users hot-plug the cables connected to the chromebook or to the external display.
>
> drivers/net/ethernet/intel/igb/igb_main.c | 5 +++++
> 1 file changed, 5 insertions(+)
>

Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@xxxxxxxxx> (A Contingent worker at Intel)