Re: [PATCH net 1/4] igc: fix page fault when thunderbolt is unplugged

On Fri, 20 Aug 2021 08:59:12 -0700 Tony Nguyen wrote:

From: Aaron Ma <redacted>

After unplug thunderbolt dock with i225, pciehp interrupt is triggered,
remove call will read/write mmio address which is already disconnected,
then cause page fault and make system hang.

Check PCI state to remove device safely.

Trace:
BUG: unable to handle page fault for address: 000000000000b604
Oops: 0000 [#1] SMP NOPTI
RIP: 0010:igc_rd32+0x1c/0x90 [igc]
Call Trace:
igc_ptp_suspend+0x6c/0xa0 [igc]
igc_ptp_stop+0x12/0x50 [igc]
igc_remove+0x7f/0x1c0 [igc]
pci_device_remove+0x3e/0xb0
__device_release_driver+0x181/0x240

Fixes: 13b5b7fd6a4a ("igc: Add support for Tx/Rx rings")
Fixes: b03c49cde61f ("igc: Save PTP time before a reset")

Seems like a whack-a-mole that should be addressed a little bit more
systematically. Why not return ~0 if hw_addr is NULL? That's what would
happen first time timeout is hit, right? Please consider this.

Pulled, thanks!