On Mon, Jul 02, 2018 at 06:52:44PM -0400, Sinan Kaya wrote:

This is what happens when you insert a fatal error to a hotplug slot. See
multiple link up/down messages.

/_#_[__333.699731]_pcieport_0001:00:00.0:_AER:_Uncorrected_(Fatal)_error_received:_id=0000
[  333.748116] pcieport 0001:00:00.0: PCIe Bus Error: severity=Uncorrected (Fatal), type=Transaction Layer, id
[  333.816044] pcieport 0001:00:00.0:   device [17cb:0404] error status/mask=00040000/00400000
[  333.871581] pcieport 0001:00:00.0:    [18] Malformed TLP (First)
[  333.914675] pcieport 0001:00:00.0:   TLP Header: 40000001 000000ff 00000000 00000000
[  333.968397] pciehp 0001:00:00.0:pcie004: Slot(2): Link Down
[  334.043234] iommu: Removing device 0001:01:00.4 from group 0
[  334.095952] iommu: Removing device 0001:01:00.3 from group 0
[  334.144644] iommu: Removing device 0001:01:00.2 from group 0
[  334.194653] iommu: Removing device 0001:01:00.1 from group 0
[  334.243564] pciehp 0001:00:00.0:pcie004: Slot(2): Link Up
[  334.282556] iommu: Removing device 0001:01:00.0 from group 0
[  334.330994] pciehp 0001:00:00.0:pcie004: Slot(2): Link Up event queued;
currently getting powered off
[  334.890587] pciehp 0001:00:00.0:pcie004: Timeout on hotplug command
0x13f1 (issued 282900 msec ago)
[  335.070190] pciehp 0001:00:00.0:pcie004: Slot(2): Link Down
[  335.106960] pciehp 0001:00:00.0:pcie004: Slot(2): Link Down event queued; currently getting powered on
[  335.191119] pcieport 0001:00:00.0: AER: Device recovery failed
[  346.590153] pciehp 0001:00:00.0:pcie004: Timeout on hotplug command 0x17f1 (issued 10250 msec ago)


Since DPC/AER patch to refactor fatal error handling, both hotplug
driver and AER/DPC driver will try removing devices and perform enumeration on
link events/AER events.

Perfect environment for race condition without a change.

Try to mask hotplug interrupts during AER/DPC fatal error handling.

Changes from v4:
* add mask_irq() and unmask_irq() callbacks to struct pcie_driver
* refactor reset_slot() to use pciehp_mask_irq() an pciehp_unmask_irq()

Sinan Kaya (3):
  PCI: pciehp: implement mask and unmask interrupt functions
  PCI: pciehp: reuse pciehp_mask/unmask_irq() in reset_slot()
  PCI: Mask and unmask hotplug interrupts during reset

 drivers/pci/hotplug/pciehp.h      |  2 ++
 drivers/pci/hotplug/pciehp_core.c | 19 +++++++++++++++++++
 drivers/pci/hotplug/pciehp_hpc.c  | 36 ++++++++++++++++++++++++++++--------
 drivers/pci/pcie/err.c            | 11 +++++++++++
 drivers/pci/pcie/portdrv.h        |  2 ++
 5 files changed, 62 insertions(+), 8 deletions(-)

There's been a ton of discussion about this, and I didn't see a clear
consensus emerge, so I'm going to drop it for now.  If it's still
needed, please repost it and I'll watch for reviewers.

Bjorn