The check_alu_op function in kernel/bpf/verifier.c in the Linux kernel through 4.4 allows local users to cause a denial of service (memory corruption) or possibly have unspecified other impact by leveraging incorrect sign extension.
https://www.exploit-db.com/exploits/45058/
https://www.exploit-db.com/exploits/45010/
https://www.exploit-db.com/exploits/44298/
https://www.debian.org/security/2017/dsa-4073
https://usn.ubuntu.com/usn/usn-3523-2/
https://usn.ubuntu.com/3633-1/
https://usn.ubuntu.com/3619-2/
https://usn.ubuntu.com/3619-1/
https://github.com/torvalds/linux/commit/95a762e2c8c942780948091f8f2a4f32fce1ac6f
https://bugs.chromium.org/p/project-zero/issues/detail?id=1454
http://www.securityfocus.com/bid/102288