In the Linux kernel, the following vulnerability has been resolved: um: Add winch to winchhandlers before registering winch IRQ Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winchhandlers list. If that happens, registerwinchirq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winchcleanup(). Avoid the race by adding the winch to the winchhandlers list before registering the IRQ, and rolling back if umrequestirq() fails.