apparently random segfault

Bug report from Debian BTS: http://bugs.debian.org/692199

According to the bug reporter, this segfault seems to be entirely random (periodic, once a day), and a quick look through his conkyrc (attached, and also accessible from Debian BTS #692199) doesn't turn up anything particularly likely to cause a crash. Here's a backtrace:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff4c3aaba in vfprintf () from /lib/x86_64-linux-gnu/libc.so.6

(gdb) bt
#0 0x00007ffff4c3aaba in vfprintf ()from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007ffff4c614a2 in vsnprintf ()from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00007ffff4c43313 in snprintf ()from /lib/x86_64-linux-gnu/libc.so.6
#3 0x000000000045d61b in print_top (obj=0x6d2ee0, p=0x6d33c3 "", p_max_size=15613)
at ../../src/top.c:1002
#4 0x0000000000430b25 in generate_text_internal (p=0x6d33c3 "", p_max_size=15613,
root=..., cur=0x685bc0) at ../../src/conky.c:2184
#5 0x00000000004317b8 in generate_text () at ../../src/conky.c:2427
#6 0x0000000000435424 in update_text () at ../../src/conky.c:3455
#7 0x00000000004357ff in main_loop () at ../../src/conky.c:3546
#8 0x000000000043d265 in main (argc=3, argv=0x7fffffffe528)
at ../../src/conky.c:5957

$ conky -V
Conky 1.9.0 compiled Fri May 11 06:08:41 UTC 2012 for Linux 2.6.32-5-amd64 (x86_64)

Compiled in features:

System config file: /etc/conky/conky.conf
Package library path: /usr/lib/conky

X11:
* Xdamage extension
* XDBE (double buffer extension)
* Xft
* ARGB visual

Music detection:
* Audacious
* MPD
* MOC
* XMMS2

General:
* math
* hddtemp
* portmon
* Curl
* RSS
* Weather (METAR)
* Weather (XOAP)
* wireless
* config-output
* Imlib2
* apcupsd
* iostats
* ncurses
* Lua

Lua bindings:
* Cairo
* Imlib2