CVE-2026-31606

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_hid: don't call cdev_init while cdev in use

When calling unbind, then bind again, cdev_init reinitialized the cdev,
even though there may still be references to it. That's the case when
the /dev/hidg* device is still opened. This obviously unsafe behavior
like oopes.

This fixes this by using cdev_alloc to put the cdev on the heap. That
way, we can simply allocate a new one in hidg_bind.