The do_check function in kernel/bpf/verifier.c in the Linux kernel before 4.11.1 does not make the allow_ptr_leaks value available for restricting the output of the print_bpf_insn function, which allows local users to obtain sensitive address information via crafted bpf system calls.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0d0e57697f162da4aa218b5feafe614fb666db07
www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.11.1
www.securityfocus.com/bid/98635
bugs.chromium.org/p/project-zero/issues/detail?id=1251
github.com/torvalds/linux/commit/0d0e57697f162da4aa218b5feafe614fb666db07
source.android.com/security/bulletin/2017-09-01
www.exploit-db.com/exploits/42048/