Memory layout

Below is the memory layout listed from top to bottom in the memory space.

• Kernel space
  • Access this region can cause segmentation fault.
• Stack
  • Include function calls, local variables.
  • Deep recursion and large local variable variable allocation can cause stack overflow.
  • Grow downward.
• Unused memory
• Heap
  • Malloc/new dynamic allocations
  • Invalid free/deref can cause segmentation fault.
  • Grow upward
• BSS
  • Uninitialized global variables
• Data
  • Initialized global variables
• Text
  • Compiled code
• NULL (memory address 0x0)
  • Deref can cause segmentation fault here.

Common memory bugs

• Segmentation fault
  • A segmentation fault occurs when a program tries to access a memory region it is not allowed to. Some examples are listed below.
    • Read/write outside of array bounds
    • Dereferencing a null or dangling pointer
• Stack overflow
  • A stack overflow happens when a program uses too much stack memory. Some examples are listed below.
    • Deep recursion
    • Large local variable allocation

See also