On Mon, Dec 08, 2014 at 09:44:05AM +0000, David Laight wrote: > From: Greg Kroah-Hartman > > On Fri, Dec 05, 2014 at 09:03:57PM +0100, Sebastian Andrzej Siewior wrote: > > > Consider the following scenario: > > > - plugin a webcam > > > - play the stream via gst-launch-0.10 v4l2src device=/dev/video0 > > > - remove the USB-HCD during playback via "rmmod $HCD" > > > > > > and now wait for the crash > > > > Which you deserve, why did you ever remove a kernel module? That's racy > > and _never_ recommended, which is why it never happens automatically and > > only root can do it. > > Really drivers and subsystems should have the required locking (etc) to > ensure that kernel modules can either be unloaded, or that the unload > request itself fails if the device is busy. > > It shouldn't be considered a 'shoot self in foot' operation. > OTOH there are likely to be bugs. This is not always the case, sorry, removing a kernel module is a known racy condition, and sometimes adding all of the locking required to try to make it "safe" just isn't worth it overall, as this is something that _only_ a developer does. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
