Before revision: Despite good design, however, it is possible that a third task M of medium priority (p(L) < p(M) < p(H), where p(x) represents the priority for task (x)) becomes runnable during L '' 's use of R. At this point, M being higher in priority than L, preempts L (since M does not depend on R), causing L to not be able to relinquish R promptly, in turn causing H—the highest priority process—to be unable to run (that is, H suffers unexpected blockage indirectly caused by lower priority tasks like M).
After revision: Despite good design, however, it is possible that a third task M of medium priority (p(L) < p(M) < p(H), where p(x) represents the priority for task (x)) becomes runnable during L 's use of R. At this point, M being higher in priority than L, preempts L (since M does not depend on R), causing L to not be able to relinquish R promptly, in turn causing H—the highest priority process—to be unable to run (that is, H suffers unexpected blockage indirectly caused by lower priority tasks like M).