Description of problem:
The huge_memory.c THP page fault was allowed to run if vm_ops was null (which would succeed for /dev/zero MAP_PRIVATE, as the f_op->mmap wouldn't setup a special vma->vm_ops and it would fallback to regular anonymous memory) but other THP logics weren't fully activated for vmas with vm_file not NULL (/dev/zero has a not NULL vma->vm_file).
Unprivileged local user could use this flaw to crash the server.
Upstream patch: 78f11a255749d09025f54d4e2df4fbcb031530e2
The versions of the Linux kernel as shipped with Red Hat Enterprise Linux 4, 5, and Red Hat Enterprise MRG are not affected because they do not provide support for THP (Transparent Huge Pages). This has been addressed in Red Hat Enterprise Linux 6 via https://rhn.redhat.com/errata/RHSA-2011-0928.html.
This issue was assigned the name CVE-2011-2479:
This issue has been addressed in following products:
Red Hat Enterprise Linux 6
Via RHSA-2011:0928 https://rhn.redhat.com/errata/RHSA-2011-0928.html