ASE shutdown because this process was holding a spinlock when it hit a serious error (the timeslice). Spinlocks are used to give a process exclusive access to a critical system resource, usually for just a short period of time. ASE will always shutdown when a spid encounters a serious error while holding a spinlock.
Unfortunately the rest of the output doesn't give much in the way of clues as to what was going on - the function names in the stacktrace all have to do with handling the error.
My recommendation would be to configure for a shared memory dump on the "timeslice" error type so more information can be captured if this happens again.
-bret
