(RHSA-2016:1489) Important: kernel security, bug fix, and enhancement update

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

Security Fix(es):

• A flaw was found in the way certain interfaces of the Linux kernel’s Infiniband subsystem used write() as bi-directional ioctl() replacement, which could lead to insufficient memory security checks when being invoked using the splice() system call. A local unprivileged user on a system with either Infiniband hardware present or RDMA Userspace Connection Manager Access module explicitly loaded, could use this flaw to escalate their privileges on the system. (CVE-2016-4565, Important)

Red Hat would like to thank Jann Horn for reporting this issue.

Bug Fix(es):

• When providing some services and using the Integrated Services Digital Network (ISDN), the system could terminate unexpectedly due to the call of the tty_ldisc_flush() function. The provided patch removes this call and the system no longer hangs in the described scenario. (BZ#1337442)

• After upgrading the kernel, CPU load average increased compared to the prior kernel version due to the modification of the scheduler. The provided patchset makes the calculation algorithm of this load average roll back to the status of the previous system version thus resulting in relatively lower values in the same system load. (BZ#1343014)

Enhancement(s):

• With this update, a patchset has been applied which adds support for Intel Xeon v4 processors. (BZ#1334809)