Ubuntu Security Notice 2447-2 – USN-2447-1 fixed vulnerabilities in the Linux kernel. Due to an unrelated regression TCP Throughput drops to zero for several drivers after upgrading. This update fixes the problem. An information leak in the Linux kernel was discovered that could leak the high 16 bits of the kernel stack address on 32-bit Kernel Virtual Machine (KVM) paravirt guests. A user in the guest OS could exploit this leak to obtain information that could potentially be used to aid in attacking the kernel. Rabin Vincent, Robert Swiecki, Russell King discovered that the ftrace subsystem of the Linux kernel does not properly handle private syscall numbers. A local user could exploit this flaw to cause a denial of service (OOPS). A flaw in the handling of malformed ASCONF chunks by SCTP (Stream Control Transmission Protocol) implementation in the Linux kernel was discovered. Various other issues were also addressed.