The MITRE CVE dictionary describes this issue as:
The __sys_sendmsg function in net/socket.c in the Linux kernel before 3.1 allows local users to cause a denial of service (system crash) via crafted use of the sendmmsg system call, leading to an incorrect pointer dereference.
Find out more about CVE-2011-4594 from the
MITRE CVE dictionary dictionary and
This issue did not affect the versions of Linux kernel as shipped with Red Hat
Enterprise Linux 4, 5 and Red Hat Enterprise MRG as they did not provide support for the sendmmsg syscall. This has been addressed in Red Hat Enterprise Linux 6 via https://rhn.redhat.com/errata/RHSA-2012-0350.html.