On Monday, November 25, 2013 02:59:44 PM Bjorn Helgaas wrote: > On Sat, Nov 23, 2013 at 5:17 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive) > > I'm seeing traces analogous to the one below in Thunderbolt testing: [...] > > (Mika Westerberg sees them too in his tests). > > > > Some investigation documented in kernel bug #65281 lead me to the > > conclusion that the source of the problem is the device_del() in > > pci_stop_dev() as it now causes the sysfs directory of the device > > to be removed recursively along with all of its subdirectories. > > That includes the sysfs directory of the device's subordinate > > bus (dev->subordinate) and its "power" group. > > > > Consequently, when pci_remove_bus() is called for dev->subordinate > > in pci_remove_bus_device(), it calls device_unregister(&bus->dev), > > but at this point the sysfs directory of bus->dev doesn't exist any > > more and its "power" group doesn't exist either. Thus, when > > dpm_sysfs_remove() called from device_del() tries to remove that > > group, it triggers the above warning. > > > > That indicates a logical mistake in the design of > > pci_stop_and_remove_bus_device(), which causes bus device objects > > to be left behind their parents (bridge device objects) and can be > > fixed by moving the device_del() from pci_stop_dev() into > > pci_destroy_dev(), so pci_remove_bus() can be called for the > > device's subordinate bus before the device itself is unregistered > > from the hierarchy. Still, the driver, if any, should be detached > > from the device in pci_stop_dev(), so use device_release_driver() > > directly from there. > > > > References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6 > > Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Applied to for-linus for v3.13. Thanks a lot for all your work on this issue! Thanks, and no problem! :-) Rafael -- 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
