An issue was discovered in fs/gfs2/rgrp.c in the Linux kernel before 4.8. A use-after-free is caused by the functions gfs2_clear_rgrpd and read_rindex_entry.
https://support.f5.com/csp/article/K31332013
https://seclists.org/bugtraq/2019/Nov/11
http://packetstormsecurity.com/files/154951/Kernel-Live-Patch-Security-Notice-LSN-0058-1.html