Lukas Wunner 464da38ba8 PCI: pciehp: Fix infinite loop in IRQ handler upon power fault ... commit 23584c1ed3 upstream. The Power Fault Detected bit in the Slot Status register differs from all other hotplug events in that it is sticky: It can only be cleared after turning off slot power. Per PCIe r5.0, sec. 6.7.1.8: If a power controller detects a main power fault on the hot-plug slot, it must automatically set its internal main power fault latch [...]. The main power fault latch is cleared when software turns off power to the hot-plug slot. The stickiness used to cause interrupt storms and infinite loops which were fixed in 2009 by commits 5651c48cfa ("PCI pciehp: fix power fault interrupt storm problem") and 99f0169c17 ("PCI: pciehp: enable software notification on empty slots"). Unfortunately in 2020 the infinite loop issue was inadvertently reintroduced by commit 8edf5332c3 ("PCI: pciehp: Fix MSI interrupt race"): The hardirq handler pciehp_isr() clears the PFD bit until pciehp's power_fault_detected flag is set. That happens in the IRQ thread pciehp_ist(), which never learns of the event because the hardirq handler is stuck in an infinite loop. Fix by setting the power_fault_detected flag already in the hardirq handler. Link: https://bugzilla.kernel.org/show_bug.cgi?id=214989 Link: https://lore.kernel.org/linux-pci/DM8PR11MB5702255A6A92F735D90A4446868B9@DM8PR11MB5702.namprd11.prod.outlook.com Fixes: 8edf5332c3 ("PCI: pciehp: Fix MSI interrupt race") Link: https://lore.kernel.org/r/66eaeef31d4997ceea357ad93259f290ededecfd.1637187226.git.lukas@wunner.de Reported-by: Joseph Bao <joseph.bao@intel.com> Tested-by: Joseph Bao <joseph.bao@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v4.19+ Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-02-05 12:35:36 +01:00
..
acpi_pcihp.c
acpiphp.h
acpiphp_core.c
acpiphp_glue.c	ACPI / hotplug / PCI: Fix reference count leak in enable_slot()	2021-05-22 11:38:28 +02:00
acpiphp_ibm.c
cpci_hotplug.h
cpci_hotplug_core.c
cpci_hotplug_pci.c
cpcihp_generic.c
cpcihp_zt5550.c
cpcihp_zt5550.h
cpqphp.h
cpqphp_core.c
cpqphp_ctrl.c
cpqphp_nvram.c
cpqphp_nvram.h
cpqphp_pci.c
cpqphp_sysfs.c
ibmphp.h
ibmphp_core.c
ibmphp_ebda.c	PCI: ibmphp: Fix double unmap of io_mem	2021-09-22 12:26:44 +02:00
ibmphp_hpc.c
ibmphp_pci.c
ibmphp_res.c
Kconfig
Makefile
pci_hotplug_core.c
pciehp.h
pciehp_core.c
pciehp_ctrl.c
pciehp_hpc.c	PCI: pciehp: Fix infinite loop in IRQ handler upon power fault	2022-02-05 12:35:36 +01:00
pciehp_pci.c
pnv_php.c
rpadlpar.h
rpadlpar_core.c
rpadlpar_sysfs.c
rpaphp.h
rpaphp_core.c
rpaphp_pci.c
rpaphp_slot.c
s390_pci_hpc.c
shpchp.h
shpchp_core.c
shpchp_ctrl.c
shpchp_hpc.c
shpchp_pci.c
shpchp_sysfs.c
TODO	PCI: ibmphp: Fix double unmap of io_mem	2021-09-22 12:26:44 +02:00