Handling stack overflows in embedded systems

Question

In embedded software, how do you handle a stack overflow in a generic way? I come across some processor which does protect in hardware way like recent AMD processors. There are

Answer 1

While embedded stack overflow can be caused by recursive functions getting out of hand, it can also be caused by errant pointer usage (although this could be considered another type of error), and normal system operation with an undersized stack. In other words, if you don't profile your stack usage it can occur outside of a defect or bug situation.

Before you can "handle" stack overflow you have to identify it. A good method for doing this is to load the stack with a pattern during initialization and then monitor how much of the pattern disappears during run-time. In this fashion you can identify the highest point the stack has reached.

The pattern check algorithm should execute in the opposite direction of stack growth. So, if the stack grows from 0x1000 to 0x2000, then your pattern check can start at 0x2000 to increase efficiency. If your pattern was 0xAA and the value at 0x2000 contains something other than 0xAA, you know you've probably got some overflow.

You should also consider placing an empty RAM buffer immediately after the stack so that if you do detect overflow you can shut down the system without losing data. If your stack is followed immediately by heap or SRAM data then identifying an overflow will mean that you have already suffered corruption. Your buffer will protect you for a little bit longer. On a 32-bit micro you should have enough RAM to provide at least a small buffer.