The assoc_array_insert_into_terminal_node function in lib/assoc_array.c in the Linux kernel before 4.13.11 mishandles node splitting, which allows local users to cause a denial of service (NULL pointer dereference and panic) via a crafted application, as demonstrated by the keyring key type, and key addition and link creation operations.
https://usn.ubuntu.com/3698-2/
https://usn.ubuntu.com/3698-1/
https://github.com/torvalds/linux/commit/ea6789980fdaa610d7eb63602c746bf6ec70cd2b
https://bugzilla.redhat.com/show_bug.cgi?id=1501215
https://access.redhat.com/errata/RHSA-2018:0151
http://www.securityfocus.com/bid/101678
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.11