When using deathmetal-drumkit, Hydrogen 0.9.3 crashes very frequently with some patterns (for me it was easy to find such patterns, some work better than others ). The other drumkits I've used work fine for me. This was on OpenBSD 4.5-current, with the current OpenBSD-specific patches applied (http://www.openbsd.org/cgi-bin/cvsweb/ports/audio/hydrogen/patches/).
I got a very similar backtrace in gdb as in this bug: https://bugs.launchpad.net/ubuntu/+source/hydrogen/+bug/147470. I found out that the trigger was in file hydrogen-0.9.3/src/lib/Hydrogen.cpp, which contains out-of-bounds accesses on sample buffers. I also checked out the 0.9.4-rc1-1 source code, this bug also exists there in file libs/hydrogen/src/sampler/sampler.cpp. Attached is a patch that fixes these crashes.