(RHSA-2021:3987) Important: kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

• kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free (CVE-2020-36385)

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

• kernel: powerpc: KVM guest OS users can cause host OS memory corruption (CVE-2021-37576)

• kernel: use-after-free in show_numa_stats function (CVE-2019-20934)

• kernel: SVM nested virtualization issue in KVM (AVIC support) (CVE-2021-3653)

• kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE) (CVE-2021-3656)

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):

• A race between i40e_ndo_set_vf_mac() and i40e_vsi_clear() in the i40e driver causes a use after free condition of the kmalloc-4096 slab cache. (BZ#1980333)