• Execution flow
• Memory management
  • Memory layout
  • Common memory bugs
• Dependency management
• See also

Execution flow

1. The GNU Compiler Collection (GCC) converts our C code into an assembly specific to our CPU architecture like x86_64, amd64, arm64.
2. The assembler compiles the assembly into a group of binaries, also called object files.
3. The linker combines the object files and libraries into the final binary.
4. The machine executes the final binary.

Memory management

Memory layout

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

• Kernel space
  • Accessing this region can cause segmentation fault.
• Stack
  • Include function calls, local variables.
  • Deep recursion and large local variable allocation can cause stack overflow.
  • Grow downward.
• Unused memory
• Heap
  • Malloc/new dynamic allocations
  • Invalid free/dereferencing can cause segmentation fault.
  • Grow upward.
• BSS
  • Uninitialized global variables
• Data
  • Initialized global variables
• Text
  • Compiled code
• NULL (memory address 0x0)
  • Dereferencing this 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
    • Use/free a null pointer
    • Use-after-free
    • Double free
• 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

Dependency management

See also