C Programming Interview Questions Part 26: Causes of memory leaks in embedded systems?

C Programming Interview Questions Part 26
What are the common causes of memory leaks in embedded systems?
1. Dynamic Memory Allocation Without Freeing:
Memory allocated using malloc, calloc, or realloc but never freed using free().
2. Lost References:
A pointer to dynamically allocated memory is overwritten or goes out of scope, making the memory unreachable.
3. Multiple Allocations Without Freeing Previous Memory:
Allocating memory to the same pointer repeatedly without freeing the previously allocated block.
4. Improper Use of Pointers in Structures:
Structs that contain pointers may lead to leaks if their internal memory isn’t freed before the struct is deallocated.
5. Mismatched Allocation/Deallocation:
Using malloc with delete or new with free() in mixed C/C++ codebases.
6. Recursive Calls or Loops with Allocations:
Memory allocations in recursive functions or infinite loops without corresponding deallocations.
7. Failure to Free on All Execution Paths:
Not freeing memory in all return paths of a function, especially in error-handling conditions.
8. Memory Fragmentation:
In long-running embedded systems, fragmentation can cause inefficient memory use, eventually leading to allocation failures or leaks.
9. Third-Party Library Leaks:
Libraries that manage memory internally might leak if not properly initialized or deinitialized.
10. Improper ISR Usage:
Allocating memory inside ISRs is risky and might not be freed properly due to timing or task scheduling issues.

Prevention Tips:
• Prefer static or stack memory when possible.
• Use memory checking tools or static analyzers.
• Always pair every allocation with a clear deallocation.
• Conduct regular code reviews focused on memory management.

#cprogramming #embeddedc #memoryleaks #embeddedinterview #embeddedsoftware #firmwareengineering