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  1. 02 9月, 2020 24 次提交
  3. 21 11月, 2019 5 次提交
  5. 06 11月, 2019 1 次提交
  7. 26 5月, 2019 2 次提交
  9. 06 4月, 2019 1 次提交
    • R
      PCI/PME: Fix hotplug/sysfs remove deadlock in pcie_pme_remove() · 9546c366
      由 Rafael J. Wysocki 提交于 
      [ Upstream commit 95c80bc6952b6a5badc7b702d23e5bf14d251e7c ]

Dongdong reported a deadlock triggered by a hotplug event during a sysfs
"remove" operation:

  pciehp 0000:00:0c.0:pcie004: Slot(0-1): Link Up
  # echo 1 > 0000:00:0c.0/remove

  PME and hotplug share an MSI/MSI-X vector.  The sysfs "remove" side is:

    remove_store
       pci_stop_and_remove_bus_device_locked
	 pci_lock_rescan_remove
	 pci_stop_and_remove_bus_device
	   ...
	   pcie_pme_remove
	     pcie_pme_suspend
	       synchronize_irq        # wait for hotplug IRQ handler
	 pci_unlock_rescan_remove

  The hotplug side is:

    pciehp_ist
       pciehp_handle_presence_or_link_change
	 pciehp_configure_device
	   pci_lock_rescan_remove     # wait for pci_unlock_rescan_remove()

  INFO: task bash:10913 blocked for more than 120 seconds.

  # ps -ax |grep D
   PID TTY      STAT   TIME COMMAND
  10913 ttyAMA0  Ds+    0:00 -bash
  14022 ?        D      0:00 [irq/745-pciehp]

  # cat /proc/14022/stack
  __switch_to+0x94/0xd8
  pci_lock_rescan_remove+0x20/0x28
  pciehp_configure_device+0x30/0x140
  pciehp_handle_presence_or_link_change+0x324/0x458
  pciehp_ist+0x1dc/0x1e0

  # cat /proc/10913/stack
  __switch_to+0x94/0xd8
  synchronize_irq+0x8c/0xc0
  pcie_pme_suspend+0xa4/0x118
  pcie_pme_remove+0x20/0x40
  pcie_port_remove_service+0x3c/0x58
  ...
  pcie_port_device_remove+0x2c/0x48
  pcie_portdrv_remove+0x68/0x78
  pci_device_remove+0x48/0x120
  ...
  pci_stop_bus_device+0x84/0xc0
  pci_stop_and_remove_bus_device_locked+0x24/0x40
  remove_store+0xa4/0xb8
  dev_attr_store+0x44/0x60
  sysfs_kf_write+0x58/0x80

It is incorrect to call pcie_pme_suspend() from pcie_pme_remove() for two
reasons.

First, pcie_pme_suspend() calls synchronize_irq(), which will wait for the
native hotplug interrupt handler as well as for the PME one, because they
share one IRQ (as per the spec).  That may deadlock if hotplug is signaled
while pcie_pme_remove() is running and the latter calls
pci_lock_rescan_remove() before the former.

Second, if pcie_pme_suspend() figures out that wakeup needs to be enabled
for the port, it will return without disabling the interrupt as expected by
pcie_pme_remove() which was overlooked by commit c7b5a4e6 ("PCI / PM:
Fix native PME handling during system suspend/resume").

To fix that, rework pcie_pme_remove() to disable the PME interrupt, clear
its status and prevent the PME worker function from re-enabling it before
calling free_irq() on it, which should be sufficient.

Fixes: c7b5a4e6 ("PCI / PM: Fix native PME handling during system suspend/resume")
Link: https://lore.kernel.org/linux-pci/c7697e7c-e1af-13e4-8491-0a3996e6ab5d@huawei.comReported-by: NDongdong Liu <liudongdong3@huawei.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
[bhelgaas: add URL and deadlock details from Dongdong]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      9546c366
  11. 24 3月, 2019 1 次提交
  13. 14 11月, 2018 1 次提交
    • L
      PCI/ASPM: Fix link_state teardown on device removal · 1e37e70d
      由 Lukas Wunner 提交于 
      commit aeae4f3e upstream.

Upon removal of the last device on a bus, the link_state of the bridge
leading to that bus is sought to be torn down by having pci_stop_dev()
call pcie_aspm_exit_link_state().

When ASPM was originally introduced by commit 7d715a6c ("PCI: add
PCI Express ASPM support"), it determined whether the device being
removed is the last one by calling list_empty() on the bridge's
subordinate devices list.  That didn't work because the device is only
removed from the list slightly later in pci_destroy_dev().

Commit 3419c75e ("PCI: properly clean up ASPM link state on device
remove") attempted to fix it by calling list_is_last(), but that's not
correct either because it checks whether the device is at the *end* of
the list, not whether it's the last one *left* in the list.  If the user
removes the device which happens to be at the end of the list via sysfs
but other devices are preceding the device in the list, the link_state
is torn down prematurely.

The real fix is to move the invocation of pcie_aspm_exit_link_state() to
pci_destroy_dev() and reinstate the call to list_empty().  Remove a
duplicate check for dev->bus->self because pcie_aspm_exit_link_state()
already contains an identical check.

Fixes: 7d715a6c ("PCI: add PCI Express ASPM support")
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: stable@vger.kernel.org # v2.6.26
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1e37e70d
  15. 16 8月, 2018 1 次提交
  17. 07 8月, 2018 1 次提交
  19. 01 8月, 2018 3 次提交
    • B
      PCI/AER: Remove duplicate PCI_EXP_AER_FLAGS definition · 944d5859
      由 Bjorn Helgaas 提交于 
      PCI_EXP_AER_FLAGS was defined twice (with identical definitions), once
under #ifdef CONFIG_ACPI_APEI, and again at the top level.  This looks like
my merge error from these commits:

  fd3362cb ("PCI/AER: Squash aerdrv_core.c into aerdrv.c")
  41cbc9eb ("PCI/AER: Squash ecrc.c into aerdrv.c")

Remove the duplicate PCI_EXP_AER_FLAGS definition.

Fixes: 41cbc9eb ("PCI/AER: Squash ecrc.c into aerdrv.c")
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NOza Pawandeep <poza@codeaurora.org>
      944d5859
    • L
      PCI: pciehp: Clear spurious events earlier on resume · 79037824
      由 Lukas Wunner 提交于 
      Thunderbolt hotplug ports that were occupied before system sleep resume
with their downstream link in "off" state.  Only after the Thunderbolt
controller has reestablished the PCIe tunnels does the link go up.
As a result, a spurious Presence Detect Changed and/or Data Link Layer
State Changed event occurs.

The events are not immediately acted upon because tunnel reestablishment
happens in the ->resume_noirq phase, when interrupts are still disabled.
Also, notification of events may initially be disabled in the Slot
Control register when coming out of system sleep and is reenabled in the
->resume_noirq phase through:

  pci_pm_resume_noirq()
    pci_pm_default_resume_early()
      pci_restore_state()
        pci_restore_pcie_state()

It is not guaranteed that the events are acted upon at all:  PCIe r4.0,
sec 6.7.3.4 says that "a port may optionally send an MSI when there are
hot-plug events that occur while interrupt generation is disabled, and
interrupt generation is subsequently enabled."  Note the "optionally".

If an MSI is sent, pciehp will gratuitously turn the slot off and back
on once the ->resume_early phase has commenced.

If an MSI is not sent, the extant, unacknowledged events in the Slot
Status register will prevent future notification of presence or link
changes.

Commit 13c65840 ("PCI: pciehp: Clear Presence Detect and Data Link
Layer Status Changed on resume") fixed the latter by clearing the events
in the ->resume phase.  Move this to the ->resume_noirq phase to also
fix the gratuitous disable/enablement of the slot.

The commit further restored the Slot Control register in the ->resume
phase, but that's dispensable because as shown above it's already been
done in the ->resume_noirq phase.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
      79037824
    • L
      PCI: portdrv: Deduplicate PM callback iterator · 6ccb127b
      由 Lukas Wunner 提交于 
      Replace suspend_iter() and resume_iter() with a single function pm_iter()
to allow addition of port service callbacks for further power management
phases without having to add another iterator each time.

No functional change intended.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      6ccb127b