In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_printer: take kref only for successful open printer_open() returns -EBUSY when the character device is already open, but it increments dev->kref regardless of the return value. VFS does not call ->release() for a failed open, so every rejected second open permanently leaks one reference. Move kref_get() into the successful-open branch.
usb: gadget: f_printer: take kref only for successful open