Linux kernel stable tree (mirror) https://git.radix-linux.su/kernel/linux.git/atom?h=v6.6.39 2023-12-20T16:01:53+00:00 2023-12-20T16:01:53+00:00 Bjorn Helgaas bhelgaas@google.com 2023-12-14T15:08:56+00:00 urn:sha1:5cc8d88a1b94b900fd74abda744c29ff5845430b commit 5df12742b7e3aae2594a30a9d14d5d6e9e7699f4 upstream. This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the subsequent fix to it: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") 40613da52b13 fixed a problem where hot-adding a device with large BARs failed if the bridge windows programmed by firmware were not large enough. cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add of a device on a PCI root bus (common in the virt world) or firmware sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron 7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs. Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other problems: - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails sometimes. - Dongli reported a similar problem with hot-add of SCSI disks. - Jonathan reported a console freeze during boot on bare metal due to an error in radeon GPU initialization. Revert both patches to avoid adding these problems. This means we will again see the problems with hot-adding devices with large BARs and the NULL pointer dereferences and suspend/resume issues that 40613da52b13 and cc22522fd55e were intended to fix. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") Reported-by: Fiona Ebner <f.ebner@proxmox.com> Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com Reported-by: Dongli Zhang <dongli.zhang@oracle.com> Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com Reported-by: Jonathan Woithe <jwoithe@just42.net> Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Igor Mammedov <imammedo@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 2023-08-31T19:43:10+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-08-31T19:43:10+00:00 urn:sha1:4ad0a4c2343d3981e92df2b39fa262be62a9091a Pull powerpc updates from Michael Ellerman: - Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the configured SMT state when hotplugging CPUs into the system - Combine final TLB flush and lazy TLB mm shootdown IPIs when using the Radix MMU to avoid a broadcast TLBIE flush on exit - Drop the exclusion between ptrace/perf watchpoints, and drop the now unused associated arch hooks - Add support for the "nohlt" command line option to disable CPU idle - Add support for -fpatchable-function-entry for ftrace, with GCC >= 13.1 - Rework memory block size determination, and support 256MB size on systems with GPUs that have hotpluggable memory - Various other small features and fixes Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev, Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam Menghani, Geoff Levand, Hari Bathini, Immad Mir, Jialin Zhang, Joel Stanley, Jordan Niethe, Justin Stitt, Kajol Jain, Kees Cook, Krzysztof Kozlowski, Laurent Dufour, Liang He, Linus Walleij, Mahesh Salgaonkar, Masahiro Yamada, Michal Suchanek, Nageswara R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick Desaulniers, Omar Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell Currey, Sourabh Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav Jain, Xiongfeng Wang, Yuan Tan, Zhang Rui, and Zheng Zengkai. * tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (135 commits) macintosh/ams: linux/platform_device.h is needed powerpc/xmon: Reapply "Relax frame size for clang" powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled powerpc/iommu: Fix notifiers being shared by PCI and VIO buses powerpc/mpc5xxx: Add missing fwnode_handle_put() powerpc/config: Disable SLAB_DEBUG_ON in skiroot powerpc/pseries: Remove unused hcall tracing instruction powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n powerpc: dts: add missing space before { powerpc/eeh: Use pci_dev_id() to simplify the code powerpc/64s: Move CPU -mtune options into Kconfig powerpc/powermac: Fix unused function warning powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT powerpc: Don't include lppaca.h in paca.h powerpc/pseries: Move hcall_vphn() prototype into vphn.h powerpc/pseries: Move VPHN constants into vphn.h cxl: Drop unused detach_spa() powerpc: Drop zalloc_maybe_bootmem() powerpc/powernv: Use struct opal_prd_msg in more places ... 2023-08-31T03:23:07+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-08-31T03:23:07+00:00 urn:sha1:b6f6167ea8a424d14b41c172fe7a5f49e164f221 Pull PCI updates from Bjorn Helgaas: "Enumeration: - Add locking to read/modify/write PCIe Capability Register accessors for Link Control and Root Control - Use pci_dev_id() when possible instead of manually composing ID from dev->bus->number and dev->devfn Resource management: - Move prototypes for __weak sysfs resource files to linux/pci.h to fix 'no previous prototype' warnings - Make more I/O port accesses depend on HAS_IOPORT - Use devm_platform_get_and_ioremap_resource() instead of open-coding platform_get_resource() followed by devm_ioremap_resource() Power management: - Ensure devices are powered up while accessing VPD - If device is powered-up, keep it that way while polling for PME - Only read PCI_PM_CTRL register when available, to avoid reading the wrong register and corrupting dev->current_state Virtualization: - Avoid Secondary Bus Reset on NVIDIA T4 GPUs Error handling: - Remove unused pci_disable_pcie_error_reporting() - Unexport pci_enable_pcie_error_reporting(), used only by aer.c - Unexport pcie_port_bus_type, used only by PCI core VGA: - Simplify and clean up typos in VGA arbiter Apple PCIe controller driver: - Initialize pcie->nvecs (number of available MSIs) before use Broadcom iProc PCIe controller driver: - Use of_property_read_bool() instead of low-level accessors for boolean properties Broadcom STB PCIe controller driver: - Assert PERST# when probing BCM2711 because some bootloaders don't do it Freescale i.MX6 PCIe controller driver: - Add .host_deinit() callback so we can clean up things like regulators on probe failure or driver unload Freescale Layerscape PCIe controller driver: - Add support for link-down notification so the endpoint driver can process LINK_DOWN events - Add suspend/resume support, including manual PME_Turn_off/PME_TO_Ack handshake - Save Link Capabilities during probe so they can be restored when handling a link-up event, since the controller loses the Link Width and Link Speed values during reset Intel VMD host bridge driver: - Fix disable of bridge windows during domain reset; previously we cleared the base/limit registers, which actually left the windows enabled Marvell MVEBU PCIe controller driver: - Remove unused busn member Microchip PolarFlare PCIe controller driver: - Fix interrupt bit definitions so the SEC and DED interrupt handlers work correctly - Make driver buildable as a module - Read FPGA MSI configuration parameters from hardware instead of hard-coding them Microsoft Hyper-V host bridge driver: - To avoid a NULL pointer dereference, skip MSI restore after hibernate if MSI/MSI-X hasn't been enabled NVIDIA Tegra194 PCIe controller driver: - Revert 'PCI: tegra194: Enable support for 256 Byte payload' because Linux doesn't know how to reduce MPS from to 256 to 128 bytes for endpoints below a switch (because other devices below the switch might already be operating), which leads to 'Malformed TLP' errors Qualcomm PCIe controller driver: - Add DT and driver support for interconnect bandwidth voting for 'pcie-mem' and 'cpu-pcie' interconnects - Fix broken SDX65 'compatible' DT property - Configure controller so MHI bus master clock will be switched off while in ASPM L1.x states - Use alignment restriction from EPF core in EPF MHI driver - Add Endpoint eDMA support - Add MHI eDMA support - Add Snapdragon SM8450 support to the EPF MHI driversupport - Add MHI eDMA support - Add Snapdragon SM8450 support to the EPF MHI driversupport - Add MHI eDMA support - Add Snapdragon SM8450 support to the EPF MHI driversupport - Add MHI eDMA support - Add Snapdragon SM8450 support to the EPF MHI driver - Use iATU for EPF MHI transfers smaller than 4K to avoid eDMA setup latency - Add sa8775p DT binding and driver support Rockchip PCIe controller driver: - Use 64-bit mask on MSI 64-bit PCI address to avoid zeroing out the upper 32 bits SiFive FU740 PCIe controller driver: - Set the supported number of MSI vectors so we can use all available MSI interrupts Synopsys DesignWare PCIe controller driver: - Add generic dwc suspend/resume APIs (dw_pcie_suspend_noirq() and dw_pcie_resume_noirq()) to be called by controller driver suspend/resume ops, and a controller callback to send PME_Turn_Off MicroSemi Switchtec management driver: - Add support for PCIe Gen5 devices Miscellaneous: - Reorder and compress to reduce size of struct pci_dev - Fix race in DOE destroy_work_on_stack() - Add stubs to avoid casts between incompatible function types - Explicitly include correct DT includes to untangle headers" * tag 'pci-v6.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (96 commits) PCI: qcom-ep: Add ICC bandwidth voting support dt-bindings: PCI: qcom: ep: Add interconnects path PCI: qcom-ep: Treat unknown IRQ events as an error dt-bindings: PCI: qcom: Fix SDX65 compatible PCI: endpoint: Add kernel-doc for pci_epc_mem_init() API PCI: epf-mhi: Use iATU for small transfers PCI: epf-mhi: Add support for SM8450 PCI: epf-mhi: Add eDMA support PCI: qcom-ep: Add eDMA support PCI: epf-mhi: Make use of the alignment restriction from EPF core PCI/PM: Only read PCI_PM_CTRL register when available PCI: qcom: Add support for sa8775p SoC dt-bindings: PCI: qcom: Add sa8775p compatible PCI: qcom-ep: Pass alignment restriction to the EPF core PCI: Simplify pcie_capability_clear_and_set_word() control flow PCI: Tidy config space save/restore messages PCI: Fix code formatting inconsistencies PCI: Fix typos in docs and comments PCI: Fix pci_bus_resetable(), pci_slot_resetable() name typos PCI: Simplify pci_dev_driver() ... 2023-08-29T16:03:57+00:00 Bjorn Helgaas bhelgaas@google.com 2023-08-29T16:03:57+00:00 urn:sha1:43cc31da9146f9ce60e4a03d96ef0807c2cdac94 - Reorder struct pci_dev to avoid holes and reduce size (Christophe JAILLET) - Change pdev->rom_attr_enabled to single bit since it's only a boolean value (Christophe JAILLET) - Use struct_size() in pirq_convert_irt_table() instead of hand-writing it (Christophe JAILLET) - Explicitly include correct DT includes to untangle headers (Rob Herring) - Fix a DOE race between destroy_work_on_stack() and the stack-allocated task->work struct going out of scope in pci_doe() (Ira Weiny) - Use pci_dev_id() when possible instead of manually composing ID from dev->bus->number and dev->devfn (Xiongfeng Wang, Zheng Zengkai) - Move pci_create_resource_files() declarations to linux/pci.h for alpha build warnings (Arnd Bergmann) - Remove unused hotplug function declarations (Yue Haibing) - Remove unused mvebu struct mvebu_pcie.busn (Pali Rohár) - Unexport pcie_port_bus_type (Bjorn Helgaas) - Remove unnecessary sysfs ID local variable initialization (Bjorn Helgaas) - Fix BAR value printk formatting to accommodate 32-bit values (Bjorn Helgaas) - Use consistent pointer types for config access syscall get_user() and put_user() uses (Bjorn Helgaas) - Simplify AER_RECOVER_RING_SIZE definition (Bjorn Helgaas) - Simplify pci_pio_to_address() (Bjorn Helgaas) - Simplify pci_dev_driver() (Bjorn Helgaas) - Fix pci_bus_resetable(), pci_slot_resetable() name typos (Bjorn Helgaas) - Fix code and doc typos and code formatting (Bjorn Helgaas) - Tidy config space save/restore messages (Bjorn Helgaas) * pci/misc: PCI: Tidy config space save/restore messages PCI: Fix code formatting inconsistencies PCI: Fix typos in docs and comments PCI: Fix pci_bus_resetable(), pci_slot_resetable() name typos PCI: Simplify pci_dev_driver() PCI: Simplify pci_pio_to_address() PCI/AER: Simplify AER_RECOVER_RING_SIZE definition PCI: Use consistent put_user() pointer types PCI: Fix printk field formatting PCI: Remove unnecessary initializations PCI: Unexport pcie_port_bus_type PCI: mvebu: Remove unused busn member PCI: Remove unused function declarations PCI/sysfs: Move declarations to linux/pci.h PCI/P2PDMA: Use pci_dev_id() to simplify the code PCI/IOV: Use pci_dev_id() to simplify the code PCI/AER: Use pci_dev_id() to simplify the code PCI: apple: Use pci_dev_id() to simplify the code PCI/DOE: Fix destroy_work_on_stack() race PCI: Explicitly include correct DT includes x86/PCI: Use struct_size() in pirq_convert_irt_table() PCI: Change pdev->rom_attr_enabled to single bit PCI: Reorder pci_dev fields to reduce holes 2023-08-29T16:03:49+00:00 Bjorn Helgaas bhelgaas@google.com 2023-08-29T16:03:49+00:00 urn:sha1:8b524514e49670d3ab81c7dca18fdc55d82631d4 - Add locking for read/modify/write PCIe Capability Register accessors for Link Control and Root Control (Ilpo Järvinen) - Use PCIe RMW accessors for Link Control updates in PCI core, pciehp, amdgpu, radeon, mlx5, ath10k, ath11k, ath12k (Ilpo Järvinen) - Convert PCIBIOS error values in mlx5 to generic errnos (Ilpo Järvinen) - Simplify pcie_capability_clear_and_set_word() control flow (Bjorn Helgaas) * pci/pcie-rmw: PCI: Simplify pcie_capability_clear_and_set_word() control flow net/mlx5: Convert PCI error values to generic errnos PCI: Document the Capability accessor RMW improvements wifi: ath10k: Use RMW accessors for changing LNKCTL wifi: ath12k: Use RMW accessors for changing LNKCTL wifi: ath11k: Use RMW accessors for changing LNKCTL net/mlx5: Use RMW accessors for changing LNKCTL drm/radeon: Use RMW accessors for changing LNKCTL drm/amdgpu: Use RMW accessors for changing LNKCTL PCI/ASPM: Use RMW accessors for changing LNKCTL PCI: pciehp: Use RMW accessors for changing LNKCTL PCI: Make link retraining use RMW accessors for changing LNKCTL PCI: Add locking to RMW PCI Express Capability Register accessors 2023-08-24T20:38:59+00:00 Yue Haibing yuehaibing@huawei.com 2023-08-11T09:59:33+00:00 urn:sha1:ea91512ded9963d8ca98eab67d7d182a989813d9 The following declarations have never been implemented since the beginning of git history, so remove them: u8 acpiphp_get_attention_status(struct acpiphp_slot *slot); u8 cpci_get_latch_status(struct slot *slot); u8 cpci_get_adapter_status(struct slot *slot); int ibmphp_get_total_hp_slots(void); void ibmphp_free_ibm_slot(struct slot *); void pdev_enable_device(struct pci_dev *); Link: https://lore.kernel.org/r/20230811095933.28652-1-yuehaibing@huawei.com Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> 2023-08-18T13:30:22+00:00 Mahesh Salgaonkar mahesh@linux.ibm.com 2023-08-18T11:29:43+00:00 urn:sha1:77583f77ed9b1452ac62caebf09b2206da10bbf9 When certain PHB HW failure causes pHyp to recover PHB, it marks the PE state as temporarily unavailable until recovery is complete. This also triggers an EEH handler in Linux which needs to notify drivers, and perform recovery. But before notifying the driver about the PCI error it uses get_adapter_status()->rpaphp_get_sensor_state()->rtas_call(get-sensor-state) operation of the hotplug_slot to determine if the slot contains a device or not. If the slot is empty, the recovery is skipped entirely. eeh_event_handler() ->eeh_handle_normal_event() ->eeh_slot_presence_check() ->get_adapter_status() ->rpaphp_get_sensor_state() ->rtas_get_sensor() ->rtas_call(get-sensor-state) However on certain PHB failures, the RTAS call rtas_call(get-sensor-state) returns extended busy error (9902) until PHB is recovered by pHyp. Once PHB is recovered, the rtas_call(get-sensor-state) returns success with correct presence status. The RTAS call interface rtas_get_sensor() loops over the RTAS call on extended delay return code (9902) until the return value is either success (0) or error (-1). This causes the EEH handler to get stuck for ~6 seconds before it could notify that the PCI error has been detected and stop any active operations. Hence with running I/O traffic, during this 6 seconds, the network driver continues its operation and hits a timeout (netdev watchdog). ------------ [52732.244731] DEBUG: ibm_read_slot_reset_state2() [52732.244762] DEBUG: ret = 0, rets[0]=5, rets[1]=1, rets[2]=4000, rets[3]=> [52732.244798] DEBUG: in eeh_slot_presence_check [52732.244804] DEBUG: error state check [52732.244807] DEBUG: Is slot hotpluggable [52732.244810] DEBUG: hotpluggable ops ? [52732.244953] DEBUG: Calling ops->get_adapter_status [52732.244958] DEBUG: calling rpaphp_get_sensor_state [52736.564262] ------------[ cut here ]------------ [52736.564299] NETDEV WATCHDOG: enP64p1s0f3 (tg3): transmit queue 0 timed o> [52736.564324] WARNING: CPU: 1442 PID: 0 at net/sched/sch_generic.c:478 dev> [...] [52736.564505] NIP [c000000000c32368] dev_watchdog+0x438/0x440 [52736.564513] LR [c000000000c32364] dev_watchdog+0x434/0x440 ------------ On timeouts, network driver starts dumping debug information to console (e.g bnx2 driver calls bnx2x_panic_dump()), and go into recovery path while pHyp is still recovering the PHB. As part of recovery, the driver tries to reset the device and it keeps failing since every PCI read/write returns ff's. And when EEH recovery kicks-in, the driver is unable to recover the device. This impacts the ssh connection and leads to the system being inaccessible. To get the NIC working again it needs a reboot or re-assign the I/O adapter from HMC. [ 9531.168587] EEH: Beginning: 'slot_reset' [ 9531.168601] PCI 0013:01:00.0#10000: EEH: Invoking bnx2x->slot_reset() [...] [ 9614.110094] bnx2x: [bnx2x_func_stop:9129(enP19p1s0f0)]FUNC_STOP ramrod failed. Running a dry transaction [ 9614.110300] bnx2x: [bnx2x_igu_int_disable:902(enP19p1s0f0)]BUG! Proper val not read from IGU! [ 9629.178067] bnx2x: [bnx2x_fw_command:3055(enP19p1s0f0)]FW failed to respond! [ 9629.178085] bnx2x 0013:01:00.0 enP19p1s0f0: bc 7.10.4 [ 9629.178091] bnx2x: [bnx2x_fw_dump_lvl:789(enP19p1s0f0)]Cannot dump MCP info while in PCI error [ 9644.241813] bnx2x: [bnx2x_io_slot_reset:14245(enP19p1s0f0)]IO slot reset --> driver unload [...] [ 9644.241819] PCI 0013:01:00.0#10000: EEH: bnx2x driver reports: 'disconnect' [ 9644.241823] PCI 0013:01:00.1#10000: EEH: Invoking bnx2x->slot_reset() [ 9644.241827] bnx2x: [bnx2x_io_slot_reset:14229(enP19p1s0f1)]IO slot reset initializing... [ 9644.241916] bnx2x 0013:01:00.1: enabling device (0140 -> 0142) [ 9644.258604] bnx2x: [bnx2x_io_slot_reset:14245(enP19p1s0f1)]IO slot reset --> driver unload [ 9644.258612] PCI 0013:01:00.1#10000: EEH: bnx2x driver reports: 'disconnect' [ 9644.258615] EEH: Finished:'slot_reset' with aggregate recovery state:'disconnect' [ 9644.258620] EEH: Unable to recover from failure from PHB#13-PE#10000. [ 9644.261811] EEH: Beginning: 'error_detected(permanent failure)' [...] [ 9644.261823] EEH: Finished:'error_detected(permanent failure)' Hence, it becomes important to inform driver about the PCI error detection as early as possible, so that driver is aware of PCI error and waits for EEH handler's next action for successful recovery. Current implementation uses rtas_get_sensor() API which blocks the slot check state until RTAS call returns success. To avoid this, fix the PCI hotplug driver (rpaphp) to return an error (-EBUSY) if the slot presence state can not be detected immediately while PE is in EEH recovery state. Change rpaphp_get_sensor_state() to invoke rtas_call(get-sensor-state) directly only if the respective PE is in EEH recovery state, and take actions based on RTAS return status. This way EEH handler will not be blocked on rpaphp_get_sensor_state() and can immediately notify driver about the PCI error and stop any active operations. In normal cases (non-EEH case) rpaphp_get_sensor_state() will continue to invoke rtas_get_sensor() as it was earlier with no change in existing behavior. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com> Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/169235815601.193557.13989873835811325343.stgit@jupiter 2023-08-10T16:13:34+00:00 Ilpo Järvinen ilpo.jarvinen@linux.intel.com 2023-07-17T12:04:55+00:00 urn:sha1:5f75f96c61039151c193775d776fde42477eace1 As hotplug is not the only driver touching LNKCTL, use the RMW capability accessor which handles concurrent changes correctly. Suggested-by: Lukas Wunner <lukas@wunner.de> Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions") Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: "Rafael J. Wysocki" <rafael@kernel.org> 2023-08-08T19:30:00+00:00 Igor Mammedov imammedo@redhat.com 2023-07-26T12:35:18+00:00 urn:sha1:cc22522fd55e257c86d340ae9aedc122e705a435 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") changed acpiphp hotplug to use pci_assign_unassigned_bridge_resources() which depends on bridge being available, however enable_slot() can be called without bridge associated: 1. Legitimate case of hotplug on root bus (widely used in virt world) 2. A (misbehaving) firmware, that sends ACPI Bus Check notifications to non existing root ports (Dell Inspiron 7352/0W6WV0), which end up at enable_slot(..., bridge = 0) where bus has no bridge assigned to it. acpihp doesn't know that it's a bridge, and bus specific 'PCI subsystem' can't augment ACPI context with bridge information since the PCI device to get this data from is/was not available. Issue is easy to reproduce with QEMU's 'pc' machine, which supports PCI hotplug on hostbridge slots. To reproduce, boot kernel at commit 40613da52b13 in VM started with following CLI (assuming guest root fs is installed on sda1 partition): # qemu-system-x86_64 -M pc -m 1G -enable-kvm -cpu host \ -monitor stdio -serial file:serial.log \ -kernel arch/x86/boot/bzImage \ -append "root=/dev/sda1 console=ttyS0" \ guest_disk.img Once guest OS is fully booted at qemu prompt: (qemu) device_add e1000 (check serial.log) it will cause NULL pointer dereference at: void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) { struct pci_bus *parent = bridge->subordinate; BUG: kernel NULL pointer dereference, address: 0000000000000018 ? pci_assign_unassigned_bridge_resources+0x1f/0x260 enable_slot+0x21f/0x3e0 acpiphp_hotplug_notify+0x13d/0x260 acpi_device_hotplug+0xbc/0x540 acpi_hotplug_work_fn+0x15/0x20 process_one_work+0x1f7/0x370 worker_thread+0x45/0x3b0 The issue was discovered on Dell Inspiron 7352/0W6WV0 laptop with following sequence: 1. Suspend to RAM 2. Wake up with the same backtrace being observed: 3. 2nd suspend to RAM attempt makes laptop freeze Fix it by using __pci_bus_assign_resources() instead of pci_assign_unassigned_bridge_resources() as we used to do, but only in case when bus doesn't have a bridge associated (to cover for the case of ACPI event on hostbridge or non existing root port). That lets us keep hotplug on root bus working like it used to and at the same time keeps resource reassignment usable on root ports (and other 1st level bridges) that was fixed by 40613da52b13. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Link: https://lore.kernel.org/r/20230726123518.2361181-2-imammedo@redhat.com Reported-by: Woody Suwalski <terraluna977@gmail.com> Tested-by: Woody Suwalski <terraluna977@gmail.com> Tested-by: Michal Koutný <mkoutny@suse.com> Link: https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com Signed-off-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> 2023-07-18T21:52:41+00:00 Colin Ian King colin.i.king@gmail.com 2023-06-27T12:56:12+00:00 urn:sha1:5810ab21860538bce22acb6f9bb74086e493a7e2 Don't populate the arrays on the stack; instead make them static const. Link: https://lore.kernel.org/r/20230627125612.724764-1-colin.i.king@gmail.com Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>