Version-Release number of selected component:
yum-3.4.3-47.fc18

Additional info:
cmdline:        /usr/bin/python /bin/yum update
executable:     /bin/yum
kernel:         3.6.10-4.fc18.x86_64
uid:            0
ureports_counter: 1

Truncated backtrace:
subprocess.py:1143:_execute_child:OSError: [Errno 12] No se pudo asignar memoria

Traceback (most recent call last):
  File "/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 319, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 227, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 558, in doTransaction
    problems = self.downloadPkgs(downloadpkgs, callback_total=self.download_callback_total_cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 2224, in downloadPkgs
    self.plugins.run('predownload', pkglist=pkglist)
  File "/usr/lib/python2.7/site-packages/yum/plugins.py", line 187, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File "/usr/lib/yum-plugins/presto.py", line 610, in predownload_hook
    (problems, more) = downloadPkgs(conduit, pinfo, download_pkgs)
  File "/usr/lib/yum-plugins/presto.py", line 410, in downloadPkgs
    urlgrabber.grabber.parallel_wait()
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2310, in parallel_wait
    start(opts, 1)
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2182, in start
    dl.start(opts)
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2112, in start
    dl = _ExternalDownloader()
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 2035, in __init__
    stdout = subprocess.PIPE,
  File "/usr/lib64/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib64/python2.7/subprocess.py", line 1143, in _execute_child
    self.pid = os.fork()
OSError: [Errno 12] No se pudo asignar memoria

Local variables in innermost frame:
executable: '/usr/libexec/urlgrabber-ext-down'
shell: False
errpipe_read: 28
p2cread: 14
errread: None
startupinfo: None
close_fds: False
c2pread: 26
args: ['/usr/libexec/urlgrabber-ext-down']
gc_was_enabled: True
errwrite: None
cwd: None
self: <subprocess.Popen object at 0xa495c90>
p2cwrite: 25
env: None
c2pwrite: 27
errpipe_write: 29
creationflags: 0
preexec_fn: None
universal_newlines: False