在 2015/7/24 11:07, Guenter Roeck 写道: > On 07/17/2015 02:16 AM, Yijing Wang wrote: >> Rajat Jain reported a deadlock when a hierarchical hot plug >> thread and aer recovery thread both run. >> https://lkml.org/lkml/2015/3/11/861 >> >> thread 1: >> pciehp_enable_slot() >> pciehp_configure_device() >> pci_bus_add_devices() >> device_attach(dev) >> device_lock(dev) //acquire device mutex successfully >> ... >> pciehp_probe(dev) >> __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() >> pci_walk_bus() >> down_read(&pci_bus_sem) //acquire pci_bus_sem successfully >> report_error_detected(dev) >> device_lock(dev) // deadlock here >> >> We use down_write(&pci_bus_sem) to protect the bus->slots list, because the >> bus->slots list is only accessed in drivers/pci/slot.c, we could introduce >> a new local mutex to protect bus->slots, and use down_read(&pci_bus_sem) >> instead of down_write(&pci_bus_sem) to protect the bus->devices list. >> >> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx> > > I applied both patches to our system and ran a number of tests. > Works fine as far as I can see. > > Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Guenter, thanks very much! Thanks! Yijing. > > > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
