linux/drivers/pci
Johan Hovold 1e56086415 PCI/ASPM: Fix deadlock when enabling ASPM
A last minute revert in 6.7-final introduced a potential deadlock when
enabling ASPM during probe of Qualcomm PCIe controllers as reported by
lockdep:

  ============================================
  WARNING: possible recursive locking detected
  6.7.0 #40 Not tainted
  --------------------------------------------
  kworker/u16:5/90 is trying to acquire lock:
  ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pcie_aspm_pm_state_change+0x58/0xdc

              but task is already holding lock:
  ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pci_walk_bus+0x34/0xbc

              other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(pci_bus_sem);
    lock(pci_bus_sem);

               *** DEADLOCK ***

  Call trace:
   print_deadlock_bug+0x25c/0x348
   __lock_acquire+0x10a4/0x2064
   lock_acquire+0x1e8/0x318
   down_read+0x60/0x184
   pcie_aspm_pm_state_change+0x58/0xdc
   pci_set_full_power_state+0xa8/0x114
   pci_set_power_state+0xc4/0x120
   qcom_pcie_enable_aspm+0x1c/0x3c [pcie_qcom]
   pci_walk_bus+0x64/0xbc
   qcom_pcie_host_post_init_2_7_0+0x28/0x34 [pcie_qcom]

The deadlock can easily be reproduced on machines like the Lenovo ThinkPad
X13s by adding a delay to increase the race window during asynchronous
probe where another thread can take a write lock.

Add a new pci_set_power_state_locked() and associated helper functions that
can be called with the PCI bus semaphore held to avoid taking the read lock
twice.

Link: https://lore.kernel.org/r/ZZu0qx2cmn7IwTyQ@hovoldconsulting.com
Link: https://lore.kernel.org/r/20240130100243.11011-1-johan+linaro@kernel.org
Fixes: f93e71aea6 ("Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: <stable@vger.kernel.org>	# 6.7
2024-01-31 09:03:51 -06:00
..
controller PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
endpoint Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -08:00
hotplug Revert "PCI: acpiphp: Reassign resources on bridge if necessary" 2023-12-15 14:55:10 -06:00
msi PCI/MSI: Use FIELD_GET/PREP() 2023-10-24 10:54:04 -05:00
pcie PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
switch PCI: switchtec: Fix stdev_release() crash after surprise hot remove 2023-11-22 09:44:06 -06:00
access.c PCI: Move pci_clear_and_set_dword() helper to PCI header 2023-12-13 13:35:41 +00:00
ats.c PCI/ATS: Use FIELD_GET() 2023-10-24 16:55:45 -05:00
bus.c PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
doe.c PCI/DOE: Fix destroy_work_on_stack() race 2023-07-27 15:20:47 -05:00
ecam.c
host-bridge.c
iov.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
irq.c
Kconfig PCI: Replace unnecessary UTF-8 in Kconfig 2023-10-06 14:30:48 -05:00
Makefile PCI: Create device tree node for bridge 2023-08-22 14:56:09 -05:00
mmap.c
of_property.c PCI: of_property: Handle interrupt parsing failures 2023-09-29 17:33:46 -05:00
of.c PCI: of: Destroy changeset when adding PCI device node fails 2023-09-29 17:33:51 -05:00
p2pdma.c PCI/P2PDMA: Remove redundant goto 2023-10-23 12:17:52 -05:00
pci-acpi.c Merge branch 'pci/pm' 2023-10-28 13:30:59 -05:00
pci-bridge-emul.c
pci-bridge-emul.h
pci-driver.c PCI/PM: Mark devices disconnected if upstream PCIe link is down on resume 2023-09-29 17:42:00 -05:00
pci-label.c
pci-mid.c
pci-pf-stub.c
pci-stub.c
pci-sysfs.c Driver core changes for 6.7-rc1 2023-11-03 15:15:47 -10:00
pci.c PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
pci.h PCI/ASPM: Fix deadlock when enabling ASPM 2024-01-31 09:03:51 -06:00
probe.c PCI: Log bridge info when first enumerating bridge 2023-12-15 17:28:43 -06:00
proc.c
quirks.c pci-v6.8-changes 2024-01-17 16:23:17 -08:00
remove.c PCI: Create device tree node for bridge 2023-08-22 14:56:09 -05:00
rom.c
search.c PCI: Add pci_get_base_class() helper 2023-09-28 16:49:44 -05:00
setup-bus.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
setup-irq.c
setup-res.c PCI: Use resource names in PCI log messages 2023-12-15 17:28:42 -06:00
slot.c
syscall.c PCI: Use consistent put_user() pointer types 2023-08-25 08:15:13 -05:00
vc.c PCI/VC: Use FIELD_GET() 2023-10-24 16:55:45 -05:00
vgaarb.c pci-v6.7-changes 2023-11-02 14:05:18 -10:00
vpd.c PCI/VPD: Add runtime power management to sysfs interface 2023-08-11 14:19:16 -05:00
xen-pcifront.c x86: always initialize xen-swiotlb when xen-pcifront is enabling 2023-07-31 17:54:27 +02:00