(RHSA-2021:3088) Important: kernel-rt security and bug fix update

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• kernel: race condition in net/can/bcm.c leads to local privilege escalation (CVE-2021-3609)

• kernel: Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks (CVE-2021-22543)

• kernel: out-of-bounds write in xt_compat_target_from_user() in net/netfilter/x_tables.c (CVE-2021-22555)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Bug Fix(es):

• kernel-rt: update RT source tree to the RHEL-8.4.z source tree (BZ#1985050)

• kernel-rt: Merge mm/memcg: Fix kmem_cache_alloc() performance regression (BZ#1987102)