glibc bug fix update

Updated glibc packages that fix several bugs are now available.

The GNU libc (glibc) packages contain the standard C libraries used by
applications.

These updated glibc packages provide fixes for the following bugs:

* when attempting to allocate memory, the valloc() and pvalloc() functions
sometimes failed and returned the ENOMEM signal, even when sufficient
memory was available in arenas other than main, or vice versa. In these
updated packages, valloc() and pvalloc() also try to allocate memory from
other arenas, thus resolving the issue.

* on IBM System z machines, in rare cases with large applications involving
hundreds of threads, either the _mcount() function or socket system calls
could corrupt the stack pointer and potentially cause heap corruption and
application segmentation faults. In these updated packages, the _mcount()
function and socket system calls calculate the stack pointer correctly
when, on entry, it is close to the 4 GB-aligned boundary, thus resolving
the problem.

* when 12 or more shared libraries all used Thread Local Storage (TLS),
then dynamic thread local storage either misbehaved or crashed. In these
updated packages, large numbers of shared libraries are all able to use
TLS, thus resolving the issue.

All users of glibc are advised to upgrade to these updated packages, which
resolve these issues.

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

479625 - [RHEL4] Fix stack pointer corruption problem for the socket system call and mcount
479629 - [4.7] valloc() fails with ENOMEM without trying to use arenas
479630 - TLS regions 13 and 14 can not be accessed

glibc