What is the difference between a segmentation fault and a stack overflow?

For example when we call say, a recursive function, the successive calls are stored in the stack. However, due to an error if it goes on infinitely the error is 'Segmentation fault' (as seen on GCC).

Shouldn'开发者_Python百科t it have been 'stack-overflow'? What then is the basic difference between the two?

Btw, an explanation would be more helpful than wikipedia links (gone through that, but no answer to specific query).

Stack overflow is [a] cause, segmentation fault is the result.

At least on x86 and ARM, the "stack" is a piece of memory reserved for placing local variables and return addresses of function calls. When the stack is exhausted, the memory outside of the reserved area will be accessed. But the app did not ask the kernel for this memory, thus a SegFault will be generated for memory protection.

Modern processors use memory managers to protect processes from each other. The x86 memory manager has many legacy features, one of which is segmentation. Segmentation is meant to keep programs from manipulating memory in certain ways. For instance, one segment might be marked read-only and the code would be put there, while another segment is read/write and that's where your data goes.

During a stack overflow, you exhaust all of the space allocated to one of your segments, and then your program starts writing into segments that the memory manager does not permit, and then you get a segmentation fault.

A stack overflow can manifest as either an explicit stack overflow exception (depending on the compiler and architecture) or as a segmentation fault, i.e., invalid memory access. Ultimately, a stack overflow is the result of running out of stack space, and one possible result of running out of stack space is reading or writing to memory that you shouldn't access. Hence, on many architectures, the result of a stack overflow is a memory access error.

The call stack is being overflowed, however the result of the overflowing is that eventually call-related values are pushed into memory that is not part of the stack and then - SIGSEGV!