Re: [PATCH] igb: Free IRQs when device is hotplugged

From: Stephen Hemminger
Date: Mon Dec 11 2017 - 19:34:32 EST

On Mon, 11 Dec 2017 18:45:02 -0500
Lyude Paul <lyude@xxxxxxxxxx> wrote:

> Recently I got a Caldigit TS3 Thunderbolt 3 dock, and noticed that upon
> hotplugging my kernel would immediately crash due to igb:
>
> [ 680.825801] kernel BUG at drivers/pci/msi.c:352!
> [ 680.828388] invalid opcode: 0000 [#1] SMP
> [ 680.829194] Modules linked in: igb(O) thunderbolt i2c_algo_bit joydev vfat fat btusb btrtl btbcm btintel bluetooth ecdh_generic hp_wmi sparse_keymap rfkill wmi_bmof iTCO_wdt intel_rapl x86_pkg_temp_thermal coretemp crc32_pclmul snd_pcm rtsx_pci_ms mei_me snd_timer memstick snd pcspkr mei soundcore i2c_i801 tpm_tis psmouse shpchp wmi tpm_tis_core tpm video hp_wireless acpi_pad rtsx_pci_sdmmc mmc_core crc32c_intel serio_raw rtsx_pci mfd_core xhci_pci xhci_hcd i2c_hid i2c_core [last unloaded: igb]
> [ 680.831085] CPU: 1 PID: 78 Comm: kworker/u16:1 Tainted: G O 4.15.0-rc3Lyude-Test+ #6
> [ 680.831596] Hardware name: HP HP ZBook Studio G4/826B, BIOS P71 Ver. 01.03 06/09/2017
> [ 680.832168] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
> [ 680.832687] RIP: 0010:free_msi_irqs+0x180/0x1b0
> [ 680.833271] RSP: 0018:ffffc9000030fbf0 EFLAGS: 00010286
> [ 680.833761] RAX: ffff8803405f9c00 RBX: ffff88033e3d2e40 RCX: 000000000000002c
> [ 680.834278] RDX: 0000000000000000 RSI: 00000000000000ac RDI: ffff880340be2178
> [ 680.834832] RBP: 0000000000000000 R08: ffff880340be1ff0 R09: ffff8803405f9c00
> [ 680.835342] R10: 0000000000000000 R11: 0000000000000040 R12: ffff88033d63a298
> [ 680.835822] R13: ffff88033d63a000 R14: 0000000000000060 R15: ffff880341959000
> [ 680.836332] FS: 0000000000000000(0000) GS:ffff88034f440000(0000) knlGS:0000000000000000
> [ 680.836817] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 680.837360] CR2: 000055e64044afdf CR3: 0000000001c09002 CR4: 00000000003606e0
> [ 680.837954] Call Trace:
> [ 680.838853] pci_disable_msix+0xce/0xf0
> [ 680.839616] igb_reset_interrupt_capability+0x5d/0x60 [igb]
> [ 680.840278] igb_remove+0x9d/0x110 [igb]
> [ 680.840764] pci_device_remove+0x36/0xb0
> [ 680.841279] device_release_driver_internal+0x157/0x220
> [ 680.841739] pci_stop_bus_device+0x7d/0xa0
> [ 680.842255] pci_stop_bus_device+0x2b/0xa0
> [ 680.842722] pci_stop_bus_device+0x3d/0xa0
> [ 680.843189] pci_stop_and_remove_bus_device+0xe/0x20
> [ 680.843627] trim_stale_devices+0xf3/0x140
> [ 680.844086] trim_stale_devices+0x94/0x140
> [ 680.844532] trim_stale_devices+0xa6/0x140
> [ 680.845031] ? get_slot_status+0x90/0xc0
> [ 680.845536] acpiphp_check_bridge.part.5+0xfe/0x140
> [ 680.846021] acpiphp_hotplug_notify+0x175/0x200
> [ 680.846581] ? free_bridge+0x100/0x100
> [ 680.847113] acpi_device_hotplug+0x8a/0x490
> [ 680.847535] acpi_hotplug_work_fn+0x1a/0x30
> [ 680.848076] process_one_work+0x182/0x3a0
> [ 680.848543] worker_thread+0x2e/0x380
> [ 680.848963] ? process_one_work+0x3a0/0x3a0
> [ 680.849373] kthread+0x111/0x130
> [ 680.849776] ? kthread_create_worker_on_cpu+0x50/0x50
> [ 680.850188] ret_from_fork+0x1f/0x30
> [ 680.850601] Code: 43 14 85 c0 0f 84 d5 fe ff ff 31 ed eb 0f 83 c5 01 39 6b 14 0f 86 c5 fe ff ff 8b 7b 10 01 ef e8 b7 e4 d2 ff 48 83 78 70 00 74 e3 <0f> 0b 49 8d b5 a0 00 00 00 e8 62 6f d3 ff e9 c7 fe ff ff 48 8b
> [ 680.851497] RIP: free_msi_irqs+0x180/0x1b0 RSP: ffffc9000030fbf0
>
> As it turns out, normally the freeing of IRQs that would fix this is called
> inside of the scope of __igb_close(). However, since the device is
> already gone by the point we try to unregister the netdevice from the
> driver due to a hotplug we end up seeing that the netif isn't present
> and thus, forget to free any of the device IRQs.
>
> So: after unregistering the netdev in igb_remove() check whether the PCI
> device is stale and if so, free it's IRQs and tx/rx resources.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Fixes: 9474933caf21 ("igb: close/suspend race in netif_device_detach")
> Cc: Todd Fujinaka <todd.fujinaka@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/net/ethernet/intel/igb/igb_main.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index c208753ff5b7..e650348b4bd7 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -3325,6 +3325,16 @@ static void igb_remove(struct pci_dev *pdev)
>
> unregister_netdev(netdev);
>
> + /* If the PCI device has already been physically removed (e.g. user
> + * unplugged a thunderbolt dock containing our hw) then the netif will
> + * already be down, so unregistering the netdev won't free the IRQs
> + */
> + if (!pci_device_is_present(pdev)) {
> + igb_free_irq(adapter);
> + igb_free_all_tx_resources(adapter);
> + igb_free_all_rx_resources(adapter);
> + }
> +
> igb_clear_interrupt_scheme(adapter);
>
> pci_iounmap(pdev, adapter->io_addr);

This looks like you are making a special case out of something that should
be fixed in igb_close instead.

Most likely something is wrong with earlier commit.

commit 9474933caf21a4cb5147223dca1551f527aaac36
Author: Todd Fujinaka <todd.fujinaka@xxxxxxxxx>
Date: Tue Nov 15 08:54:26 2016 -0800

igb: close/suspend race in netif_device_detach

Similar to ixgbe, when an interface is part of a namespace it is
possible that igb_close() may be called while __igb_shutdown() is
running which ends up in a double free WARN and/or a BUG in
free_msi_irqs().

Extend the rtnl_lock() to protect the call to netif_device_detach() and
igb_clear_interrupt_scheme() in __igb_shutdown() and check for
netif_device_present() to avoid calling igb_clear_interrupt_scheme() a
second time in igb_close().

Also extend the rtnl lock in igb_resume() to netif_device_attach().

Signed-off-by: Todd Fujinaka <todd.fujinaka@xxxxxxxxx>
Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>


Layers on layers of workarounds does not lead to stability.