In the Linux kernel before 4.20.5, attackers can trigger a drivers/char/ipmi/ipmi_msghandler.c use-after-free and OOPS by arranging for certain simultaneous execution of the code, as demonstrated by a "service ipmievd restart" loop.
https://usn.ubuntu.com/3930-2/
https://usn.ubuntu.com/3930-1/
https://security.netapp.com/advisory/ntap-20190327-0002/
https://github.com/torvalds/linux/commit/77f8269606bf95fcb232ee86f6da80886f1dfae8
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.5
http://www.securityfocus.com/bid/107145
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00037.html