What do these OpenOCD CPU states mean?
I worked around my problem. Still very interested to learn about those states, though!

I botched the connection through port 3333, and used openocd's piping capabilities:

.gdbinit

# Open openocd and pipe data throudh stdin/stdout.
# Openocd quits after gdb exits.
target remote | /usr/local/bin/openocd -f linux_config.cfg


openocd.cfg:

gdb_port pipe


And it magically worked.