I ran into this when umounting a cryptsetup encrypted usb disk mounted on /media/disk using "umount /media/disk". Here's the trace:

~$ umount /media/disk 
*** buffer overflow detected ***: /sbin/umount.hal terminated
======= Backtrace: =========
/lib/libc.so.6(__fortify_fail+0x37)[0x7fe264fbb1a7]
/lib/libc.so.6(+0xfe060)[0x7fe264fba060]
/lib/libc.so.6(+0xfe6bb)[0x7fe264fba6bb]
/sbin/umount.hal[0x400daf]
/lib/libc.so.6(__libc_start_main+0xfd)[0x7fe264edac4d]
/sbin/umount.hal[0x400c19]
======= Memory map: ========
00400000-00402000 r-xp 00000000 fc:02 799903                             /usr/sbin/umount.hal
00601000-00602000 r--p 00001000 fc:02 799903                             /usr/sbin/umount.hal
00602000-00603000 rw-p 00002000 fc:02 799903                             /usr/sbin/umount.hal
01f62000-01f83000 rw-p 00000000 00:00 0                                  [heap]
7fe264880000-7fe264896000 r-xp 00000000 fc:02 131154                     /lib/libgcc_s.so.1
7fe264896000-7fe264a95000 ---p 00016000 fc:02 131154                     /lib/libgcc_s.so.1
7fe264a95000-7fe264a96000 r--p 00015000 fc:02 131154                     /lib/libgcc_s.so.1
7fe264a96000-7fe264a97000 rw-p 00016000 fc:02 131154                     /lib/libgcc_s.so.1
7fe264a97000-7fe264a9e000 r-xp 00000000 fc:02 131555                     /lib/librt-2.11.1.so
7fe264a9e000-7fe264c9d000 ---p 00007000 fc:02 131555                     /lib/librt-2.11.1.so
7fe264c9d000-7fe264c9e000 r--p 00006000 fc:02 131555                     /lib/librt-2.11.1.so
7fe264c9e000-7fe264c9f000 rw-p 00007000 fc:02 131555                     /lib/librt-2.11.1.so
7fe264c9f000-7fe264cb7000 r-xp 00000000 fc:02 131553                     /lib/libpthread-2.11.1.so
7fe264cb7000-7fe264eb6000 ---p 00018000 fc:02 131553                     /lib/libpthread-2.11.1.so
7fe264eb6000-7fe264eb7000 r--p 00017000 fc:02 131553                     /lib/libpthread-2.11.1.so
7fe264eb7000-7fe264eb8000 rw-p 00018000 fc:02 131553                     /lib/libpthread-2.11.1.so
7fe264eb8000-7fe264ebc000 rw-p 00000000 00:00 0 
7fe264ebc000-7fe265034000 r-xp 00000000 fc:02 131539                     /lib/libc-2.11.1.so
7fe265034000-7fe265234000 ---p 00178000 fc:02 131539                     /lib/libc-2.11.1.so
7fe265234000-7fe265238000 r--p 00178000 fc:02 131539                     /lib/libc-2.11.1.so
7fe265238000-7fe265239000 rw-p 0017c000 fc:02 131539                     /lib/libc-2.11.1.so
7fe265239000-7fe26523e000 rw-p 00000000 00:00 0 
7fe26523e000-7fe265248000 r-xp 00000000 fc:02 788784                     /usr/lib/libhal-storage.so.1.0.0
7fe265248000-7fe265447000 ---p 0000a000 fc:02 788784                     /usr/lib/libhal-storage.so.1.0.0
7fe265447000-7fe265448000 r--p 00009000 fc:02 788784                     /usr/lib/libhal-storage.so.1.0.0
7fe265448000-7fe265449000 rw-p 0000a000 fc:02 788784                     /usr/lib/libhal-storage.so.1.0.0
7fe265449000-7fe265459000 r-xp 00000000 fc:02 788786                     /usr/lib/libhal.so.1.0.0
7fe265459000-7fe265658000 ---p 00010000 fc:02 788786                     /usr/lib/libhal.so.1.0.0
7fe265658000-7fe265659000 r--p 0000f000 fc:02 788786                     /usr/lib/libhal.so.1.0.0
7fe265659000-7fe26565a000 rw-p 00010000 fc:02 788786                     /usr/lib/libhal.so.1.0.0
7fe26565a000-7fe265697000 r-xp 00000000 fc:02 131132                     /lib/libdbus-1.so.3.4.0
7fe265697000-7fe265897000 ---p 0003d000 fc:02 131132                     /lib/libdbus-1.so.3.4.0
7fe265897000-7fe265898000 r--p 0003d000 fc:02 131132                     /lib/libdbus-1.so.3.4.0
7fe265898000-7fe265899000 rw-p 0003e000 fc:02 131132                     /lib/libdbus-1.so.3.4.0
7fe265899000-7fe2658b9000 r-xp 00000000 fc:02 131534                     /lib/ld-2.11.1.so
7fe265a94000-7fe265a99000 rw-p 00000000 00:00 0 
7fe265ab6000-7fe265ab8000 rw-p 00000000 00:00 0 
7fe265ab8000-7fe265ab9000 r--p 0001f000 fc:02 131534                     /lib/ld-2.11.1.so
7fe265ab9000-7fe265aba000 rw-p 00020000 fc:02 131534                     /lib/ld-2.11.1.so
7fe265aba000-7fe265abb000 rw-p 00000000 00:00 0 
7fff45dde000-7fff45df3000 rw-p 00000000 00:00 0                          [stack]
7fff45dff000-7fff45e00000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]