In FreeJavaStackMemory() is found the following code:

OSTACK_LOCK();
mem = javastackFreeList;
javastackFreeList = 0;
OSTACK_UNLOCK();

However in DeleteExecEnv(), stack frames are placed on javastackFreeLIst
without first calling OSTACK_LOCK. The lack of concurrency control can
cause a stack frame to be dropped, or for a number of stack frames to be
freed twice. The second case would probably eventually lead to a crash.

-Theron, 22 Feb 96