In the Linux kernel, the following vulnerability has been resolved: comedi: Reinit dev-spinlock between attachments to low-level drivers struct comedi_device is the main controlling structure for a COMEDI device created by the COMEDI subsystem. It contains a member spinlock containing a spin-lock that is initialized by the COMEDI subsystem, but is reserved for use by a low-level driver attached to the COMEDI device (at least since commit 25436dc9d84f ("Staging: comedi: remove RT code")). Some COMEDI devices (those created on initialization of the COMEDI subsystem when the "comedi.comedi_num_legacy_minors" parameter is non-zero) can be attached to different low-level drivers over their lifetime using the COMEDI_DEVCONFIG ioctl command.

This can result in inconsistent lock states being reported when there is a mismatch in the spin-lock locking levels used by each low-level driver to which the COMEDI device has been attached. Fix it by reinitializing dev-spinlock before calling the low-level driver's attach function pointer if CONFIG_LOCKDEP is enabled.