In the Linux kernel 5.4.0-rc2, there is a use-after-free (read) in the __blk_add_trace function in kernel/trace/blktrace.c (which is used to fill out a blk_io_trace structure and place it in a per-cpu sub-buffer).
lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html
bugzilla.kernel.org/show_bug.cgi?id=205711
lists.debian.org/debian-lts-announce/2020/06/msg00011.html
lists.debian.org/debian-lts-announce/2020/06/msg00012.html
lists.debian.org/debian-lts-announce/2020/06/msg00013.html
security.netapp.com/advisory/ntap-20200103-0001/
usn.ubuntu.com/4342-1/
usn.ubuntu.com/4344-1/
usn.ubuntu.com/4345-1/
usn.ubuntu.com/4346-1/
www.debian.org/security/2020/dsa-4698