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Rajat Jain reported a deadlock when PCIe hot-add and AER recovery happen at
the same time:
thread 1:
pciehp_enable_slot
pciehp_configure_device
pci_bus_add_devices
pci_bus_add_device
device_attach
device_lock(dev) # acquire device lock
...
pciehp_probe
init_slot
pci_hp_register
pci_create_slot
down_write(pci_bus_sem) # deadlock here
thread 2:
aer_isr_one_error
aer_process_err_device
do_recovery
broadcast_error_message(..., report_error_detected)
pci_walk_bus(..., cb=report_error_detected, ...)
down_read(&pci_bus_sem) # acquire pci_bus_sem
report_error_detected(dev) # cb()
device_lock(dev) # deadlock here
Previously, the bus->devices and bus->slots list were protected by
pci_bus_sem. In pci_create_slot(), we held it for writing so we could
add to the bus->slots list.
Add a new local pci_slot_mutex to protect bus->slots. Hold pci_bus_sem for
reading while searching the bus->devices list.
[bhelgaas: changelog]
Link: http://lkml.kernel.org/r/CAA93t1qpPqbih+UB0McA_d_+2rVaNkXsinAUxYzK9+JXSS+L-g@mail.gmail.com
Reported-by: Rajat Jain <rajatja@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
|
||
|---|---|---|
| .. | ||
| host | ||
| hotplug | ||
| pcie | ||
| access.c | ||
| ats.c | ||
| bus.c | ||
| host-bridge.c | ||
| hotplug-pci.c | ||
| htirq.c | ||
| iov.c | ||
| irq.c | ||
| Kconfig | ||
| Makefile | ||
| msi.c | ||
| of.c | ||
| pci-acpi.c | ||
| pci-driver.c | ||
| pci-label.c | ||
| pci-stub.c | ||
| pci-sysfs.c | ||
| pci.c | ||
| pci.h | ||
| probe.c | ||
| proc.c | ||
| quirks.c | ||
| remove.c | ||
| rom.c | ||
| search.c | ||
| setup-bus.c | ||
| setup-irq.c | ||
| setup-res.c | ||
| slot.c | ||
| syscall.c | ||
| vc.c | ||
| vpd.c | ||
| xen-pcifront.c | ||