Comment 11 for bug 1007268

Ivor -

Yes, I understand that in this case it might be quite hard to narrow down to a specific query. As for the stacktraces, the server should have gdb installed and then once mysqld hangs, issue
gdb -ex "set pagination 0" -ex "thread apply all bt" --batch -p $(pidof mysqld)
or if you have gdb 6.3 or older
(echo "set pagination 0"; echo "thread apply all bt"; echo "quit"; cat /dev/zero ) | gdb -p $(pidof mysqld)