Richards, 2Demo and many others trigger an assertion when profiled with -Xprof.
The race condition in the interrupt callback handling code causes the callback queue to be occasionally empty (specific to Solaris/Hotsparc only). The same problem may manifest with safepoints since they use the same FetchTopFrame interrupt callback scheme.

#
# HotSpot Virtual Machine Error, assertion failure
#
# assert(_cancelled_list != 0, "no free callbacks")
# /home/borisw/sparc_baseline.beta/build/solaris/../../src/os/solaris/vm/os_solaris.cpp, 1493#
assertion failure
assert(_cancelled_list != 0, "no free callbacks")
/home/borisw/sparc_baseline.beta/build/solaris/../../src/os/solaris/vm/os_solaris.cpp, 1493