In the flush_tmregs_to_thread function in arch/powerpc/kernel/ptrace.c in the Linux kernel before 4.13.5, a guest kernel crash can be triggered from unprivileged userspace during a core dump on a POWER host due to a missing processor feature check and an erroneous use of transactional memory (TM) instructions in the core dump path, leading to a denial of service. https://nvd.nist.gov/vuln/detail/CVE-2018-1091
