CVE-2023-53480

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

kobject: Add sanity check for kset->kobj.ktype in kset_register()

When I register a kset in the following way: static struct kset mykset; kobjectsetname(&mykset.kobj, "mykset"); ret = ksetregister(&my_kset);

A null pointer dereference exception is occurred: [ 4453.568337] Unable to handle kernel NULL pointer dereference at \ virtual address 0000000000000028 ... ... [ 4453.810361] Call trace: [ 4453.813062] kobjectgetownership+0xc/0x34 [ 4453.817493] kobjectaddinternal+0x98/0x274 [ 4453.822005] ksetregister+0x5c/0xb4 [ 4453.825820] mykobjinit+0x44/0x1000 [mykset] ... ...

Because I didn't initialize my_kset.kobj.ktype.

According to the description in Documentation/core-api/kobject.rst: - A ktype is the type of object that embeds a kobject. Every structure that embeds a kobject needs a corresponding ktype.

So add sanity check to make sure kset->kobj.ktype is not NULL.