Hi, I've been hacking on the PCI hotplug driver otherwise known as eeepc-laptop. At one point I reliably triggered a race on resume. In the hot-unplug case, it seemed that the resume handler would try to remove the PCI device at the same time as an acpi notification (run in a workqueue) tried to do the same thing. The result was an OOPS. My conclusion is that the PCI hotplug core does not protect against multiple simultaneous removals of the same device. pciehp appears to have an analogous problem. Assuming pciehp_force is set, the resume handler can hot-unplug the device. The interrupt handler could try to hot-unplug the device at the same time. Should the resume handler take the slot mutex to avoid this problem? diff --faked-up a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -382,15 +382,18 @@ static int pciehp_resume (struct pcie_device *dev) /* reinitialize the chipset's event detection logic */ pcie_enable_notification(ctrl); t_slot = pciehp_find_slot(ctrl, ctrl->slot_device_offset); + mutex_lock(&t_slot->lock); /* Check if slot is occupied */ t_slot->hpc_ops->get_adapter_status(t_slot, &status); if (status) pciehp_enable_slot(t_slot); else pciehp_disable_slot(t_slot); + + mutex_unlock(&t_slot->lock); } return 0; } #endif /* PM */ Regards Alan -- 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
