"Mastering Memory Leak Debugging in Embedded Systems with Valgrind and GDB" An embedded system can operate correctly for hours, days, or even weeks before suddenly resetting, freezing, or behaving unpredictably. A communication task may stop responding, a sensor may return impossible values, a dynamic allocation may unexpectedly fail, or the watchdog may reset the processor without preserving enough fault information to identify the original cause. In many cases, the actual problem started much earlier. A small block of memory was allocated and never released. A pointer advanced one element beyond the end of a buffer. An object was freed while another module still retained a reference to it. An uninitialized value was used as a length, index, or address. These defects are especially dangerous in embedded systems because they often accumulate slowly and remain invisible during normal functional testing. Valgrind and GDB provide a powerful debugging combination for finding these issues. Valgrind monitors memory behavior and detects invalid operations, while GDB gives the engineer direct control over program execution, variables, stack frames, registers, and machine instructions. Although Valgrind normally runs on a supported host operating system such as Linux and not directly on bare-metal microcontrollers, it is extremely valuable when portable firmware modules are isolated and tested in a host-based environment.