Created attachment 533697 [details]
Test program

Description of problem:
On my Dell Latitude D620, with no wired network connection and the wireless connection disabled by the hardware kill switch, calling getaddrinfo("localhost") several times in a row causes an invalid free.  This is with unmodified /etc/hosts and unmodified glibc configuration files (rpm -V glibc) except for /etc/localtime.

Version-Release number of selected component (if applicable):
glibc-2.14.90-16.x86_64

How reproducible:
Almost always on my system.

Steps to Reproduce:
1. Download attached test.c.
2. make test
3. Offline with wireless hardware-disabled: valgrind ./test

Actual results:
[valgrind header]
resolve one
==3271== Invalid free() / delete / delete[]
==3271==    at 0x4C2962E: free (vg_replace_malloc.c:366)
==3271==    by 0x4F459B7: __free_in6ai (check_pf.c:426)
==3271==    by 0x4F0D444: getaddrinfo (getaddrinfo.c:2560)
==3271==    by 0x4005F4: _resolve_addr (in /home/matt/test/gai-invalid-free/test)
==3271==    by 0x400652: main (in /home/matt/test/gai-invalid-free/test)
==3271==  Address 0x51e3390 is 0 bytes inside data symbol "noai6ai_cached"
==3271== 
resolve one
resolve one
[valgrind footer]

Expected results:
[valgrind header]
resolve one
resolve one
resolve one
[valgrind footer]

Additional info:
After I upgraded from F15 to F16, this problem caused cupsd to crash, which caused gnome-settings-daemon to hang and ultimately led to the GNOME "Oh no! Something has gone wrong" screen.  The test case is a simplified version of what cupsd was doing via libaudit.