CVE 2011-1781
SystemTap 1.4, when unprivileged (aka stapusr) mode is enabled, allows local users to cause a denial of service (divide-by-zero error and OOPS) via a crafted ELF program with DWARF expressions that are not properly handled by a stap script that performs stack unwinding (aka backtracing).
See the 
CVE page on Mitre.org
for more details.
