kernel: denial of service

* A flaw was found in the way the Xen hypervisor implementation handled instruction emulation during virtual machine exits. A malicious user-space process running in an SMP guest could trick the emulator into reading a different instruction than the one that caused the virtual machine to exit. An unprivileged guest user could trigger this flaw to crash the host. This only affects systems with both an AMD x86 processor and the AMD Virtualization (AMD-V) extensions enabled. (CVE-2011-1780, Important)

* A flaw allowed the tc_fill_qdisc() function in the Linux kernel's packet scheduler API implementation to be called on built-in qdisc structures. A local, unprivileged user could use this flaw to trigger a NULL pointer dereference, resulting in a denial of service. (CVE-2011-2525, Moderate)

* A flaw was found in the way space was allocated in the Linux kernel's Global File System 2 (GFS2) implementation. If the file system was almost full, and a local, unprivileged user made an fallocate() request, it could result in a denial of service. Note: Setting quotas to prevent users from using all available disk space would prevent exploitation of this flaw. (CVE-2011-2689, Moderate)