| Message ID | 20130903153815.13638272@nehalam.linuxnetplumber.net |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, Sep 03, 2013 at 03:38:15PM -0700, Stephen Hemminger wrote: > While debugging another problem with a PCI driver, I noticed that if > device probe routine returns an error, the kernel will crash when module > is unloaded. It looks like pci_register_driver() sets drv->bus to be PCI > then in the module unload. > > module_unload > my_device_exit_module > pci_unregister_driver > bus_remove_driver > OOPS > > One way to fix this would be to have pci_register_driver clear the bus > flag (it has no reference) if an error was detected. Odd, no other buses do this, why would it matter for PCI? Maybe they just never fail their registering calls. How about putting this in the driver core instead so that all busses get fixed? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 3 Sep 2013 16:06:19 -0700 Greg KH <gregkh@linux-foundation.org> wrote: > On Tue, Sep 03, 2013 at 03:38:15PM -0700, Stephen Hemminger wrote: > > While debugging another problem with a PCI driver, I noticed that if > > device probe routine returns an error, the kernel will crash when module > > is unloaded. It looks like pci_register_driver() sets drv->bus to be PCI > > then in the module unload. > > > > module_unload > > my_device_exit_module > > pci_unregister_driver > > bus_remove_driver > > OOPS > > > > One way to fix this would be to have pci_register_driver clear the bus > > flag (it has no reference) if an error was detected. > > Odd, no other buses do this, why would it matter for PCI? Maybe they > just never fail their registering calls. > > How about putting this in the driver core instead so that all busses get > fixed? > > thanks, > > greg k-h Never mind, buggy driver -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/drivers/pci/pci-driver.c 2013-07-08 10:54:52.968241742 -0700 +++ b/drivers/pci/pci-driver.c 2013-09-03 15:34:10.112477893 -0700 @@ -1120,6 +1120,8 @@ const struct dev_pm_ops pci_dev_pm_ops = int __pci_register_driver(struct pci_driver *drv, struct module *owner, const char *mod_name) { + int err; + /* initialize common driver fields */ drv->driver.name = drv->name; drv->driver.bus = &pci_bus_type; @@ -1130,7 +1132,11 @@ int __pci_register_driver(struct pci_dri INIT_LIST_HEAD(&drv->dynids.list); /* register with core */ - return driver_register(&drv->driver); + err = driver_register(&drv->driver); + if (err) + drv->driver.bus = NULL; + + return err; } /**
While debugging another problem with a PCI driver, I noticed that if device probe routine returns an error, the kernel will crash when module is unloaded. It looks like pci_register_driver() sets drv->bus to be PCI then in the module unload. module_unload my_device_exit_module pci_unregister_driver bus_remove_driver OOPS One way to fix this would be to have pci_register_driver clear the bus flag (it has no reference) if an error was detected. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html