Device drivers interview questions

1. What is the difference in features between kernel 2.2, 2.4 and 2.6 ?

2. What are Static and Shared libraries ?

3. What is dynamic linking ? What is static linking ?

4. What are the advantages of Dynamic linking or Shared libraries ?

5. Does gcc search for both static and shared libraries ? Which is searched initially by gcc compiler ?

6. What should be done for Shared library based linking in gcc ?

7. What should be done for static library based linking in gcc ?

8. What is object file and what are symbols ?

9. Can you tell the memory layout based on Data,BSS,HEAP and STACK ?

10. What are the ways in which linux kernel can be compiled ?

11. How will get the driver added into the kernel ? What are Kconfig files ?

12. What is a kernel module ?

13. What is the difference between insmod and modprobe ?

14. How will you list the modules ?

15. How do you get the list of currently available drivers ?

16. How will you Access userspace memory from kernel ? What are the various methods ?

17. What is the use of ioctl(inode,file,cmd,arg) ApI ?

18. What is the use of the poll(file, polltable) API ?

19. What is the use of file->private_data in a device driver structure ?

20. What is a device number ?

21. What are the two types of devices drivers from VFS point of view ?

22. What are character devices ?

23. How does the character device driver adds and remove itself from the kernel ?

What is the use of register_chrdev and unregister_chrdev ?

24. What is the role of interrupts in a device driver ? How are interrupts handled in device driver ?

25. How will you make interrupt handlers as fast as possible ?

26. What are the types of softirqs ?

27. Difference between Timer Softirq and Tasklet Softirq ?

28. What are tasklets ? How are they activated ? when and How are they initialized ?

29. What is task_struct and how are task states maintained ?

30. What is rwlock and spinlock ? Briefly explain about both of them ?

31. When will you use rwlock instead of spinlock ?

32. Can spinlock/rwlock be used in Interrupt handler ?

33. Tell about the Memory Layout of a Process in Linux .

34. How will you trace the system calls made into the kernel of lInux ?

35. What is mmap ? MMAP & malloc ? MMAP & brk ? MMAP adv & dis-adv.

36. Tell the relation between Malloc and MMAP

37. Advantages of MMAP over Read ?

38. Tell the role of brk() in malloc / Tell the relation between heap and brk?

39. Example of using MMAP and MUNMAP in C ?

40. Tell about the method/steps in Linux Kernel Compilation.

41. What is Kmalloc and how does it differ from normal malloc ? or Why can’t we use malloc in kernel code ?

42. What happens as soon as a packet arrives from the network in Linux ?

43. What is a stack frame, stack pointer & frame pointer ?

44. What is a profiler ? Which one have you used ?

45. How do you determine the direction of stack growth ?