It happened again (Authentication stops working)

Since I was stumped, I asked on darwinos-users, and got a reply from Shantonu Sen (who is smart and very active on the mailing lists).

I'm going to see if I can get a sample of 'securiytd' from when this happens next and that might point to something else that I might need to sample (lookupd, DirectoryServices ...)

Otherwise, I'll have to get the kernel debug kit installed and see if I can set up remote debugging and get it to work.

Fun fun.

Update:

Here's the sample from the stalled securityd -

Analysis of sampling pid 45 every 10.000000 milliseconds
Call graph:
    979 Thread_100f
      979 0x25dcc
        979 0x2ee4
          979 0x38d4
            979 0x8080
              979 0x83e8
                979 0x9054
                  979 0x9128
                    979 0x9acc
                      979 0x9c50
                        979 0xa094
                          979 0x3eac
                            979 pthread_mutex_lock
                              979 semaphore_wait_signal_trap
                                979 semaphore_wait_signal_trap
    979 Thread_1103
      979 _pthread_body
        979 0x16a48
          979 0x16ab8
            979 0x83e8
              979 0x9054
                979 0x9128
                  979 0x136b0
                    979 0x13868
                      979 0x13dac
                        979 0x19354
                          979 0x19354
    979 Thread_1203
      979 _pthread_body
        979 0x16a48
          979 0x16ab8
            979 0x83e8
              979 0x9054
                979 0x9128
                  979 0x9acc
                    979 0x9c50
                      979 0xa094
                        979 0x3eac
                          979 pthread_mutex_lock
                            979 semaphore_wait_signal_trap
                              979 semaphore_wait_signal_trap

Total number in stack (recursive counted multiple, when >=5):

Sort by top of stack, same collapsed (when >= 5):

        semaphore_wait_signal_trap        1958

        0x19354        979

And for no real reason at all, I'm starting to wonder if maybe the RAM on that machine is bad/going bad?