An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-f232326f6966. This affects pointer types that do not define a ptr_limit.
https://www.openwall.com/lists/oss-security/2021/03/19/2
https://lists.debian.org/debian-lts-announce/2021/03/msg00035.html
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.8
http://www.openwall.com/lists/oss-security/2021/03/24/4
http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.html