Symptom:
Cisco 4451-X runs out of memory and reloads itself when QoS service-policy is attached to an interface.

Conditions:
A QoS service-policy with ACL-based classification using wildcards (<any> keyword or <0.0.0.0>) in source or destination addresses of permit/deny statements will cause a greater consumption of memory on the router.  This affects platforms with SW-based classification (like ISR4x and CSR1000v) in particular.  It can cause the memory (either control-plane or data-plane) to be depleted, especially on lower-end systems with minimal memory.