A flaw was discovered in systemtap's handling of DWARF expressions where it
did not guard against divide by zero when unwinding the stack. This can
result in a kernel div-by-zero message and possible busywait during stap
module shutdown. A div-by-zero could cause the kernel to panic and if the
kernel reboot on panic flag was set (panic_on_oops), it would cause the
system to reboot.
In order to trigger this flaw, an admin would have to enable unprivileged
mode. If an admin has enabled unprivileged mode, a normal user could use
this to crash the target machine.
A workaround is to disable unprivileged mode.
This bug only affects systemtap versions 1.4 and above. We are rebasing systemtap to an affected version in Red Hat Enterprise Linux 6.1. This flaw will not be fixed before 6.1 GA.
"If an admin has enabled unprivileged mode, a normal user could use
this to crash the target machine."
Not quite "normal" - the user would still have to be member of the "stapusr" group.
Public now via upstream commit mentioned in comment #3.
This issue has been addressed in following products:
Red Hat Enterprise Linux 6
Via RHSA-2011:0842 https://rhn.redhat.com/errata/RHSA-2011-0842.html