+When locking rules are violated, these state bits are presented in the
+locking error messages, inside curlies. A contrived example:
+
+ modprobe/2287 is trying to acquire lock:
+ (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
+
+ but task is already holding lock:
+ (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
+
+
+The bit position indicates STATE, STATE-read, for each of the states listed
+above, and the character displayed in each indicates:
+
+ '.' acquired while irqs disabled and not in irq context
+ '-' acquired in irq context
+ '+' acquired with irqs enabled
+ '?' acquired in irq context with irqs enabled.
+
+Unused mutexes cannot be part of the cause of an error.
+
+