Comment 11 for bug 1040735

Threads 21-12 are idling I/O threads.
Thread 11 is the lock timeout thread, idle.
Thread 10 is the error monitor thread waiting to acquire srv_innodb_monitor_mutex.
Thread 9 is the monitor thread waiting to acquire the buffer pool mutex, it holds LRU and free list mutexes.
Thread 8 is the LRU dump thread, idle.
Thread 7 is the InnoDB master thread doing buffer flush, waiting to acquire the buffer pool mutex.
Thread 6 is the purge worker thread, waiting to lock the index tree.
Thread 5 is the signal handler thread, idle.
Thread 4 is the slave I/O thread.
Thread 3 is the slave SQL thread, waiting to acquire the buffer pool mutex.
Thread 2 is a cached MySQL connection thread.
Thread 1 is the main server thread.

It is not apparent which of the threads deadlock here, but it's a reasonably small number of threads for further analysis.