Linux Quiz on semaphores

Quiz on linux Semaphores

1. Race condition occur when

There is uncontrolled access to data
There is uncontrolled access to shared data
Every time kernel accesses user space data
Every time user communicates with kernel


2. The code that is surrounded by a semaphore is termed as

Critical section
Sema section
Zero section
Muted section


3. To use a semphore as a mutex, semaphore needs to be initalized to the value of

0
1
-1
2


4. Which of the following will declare and initialize a mutex

DECLARE_MUTEX
SEMA_INIT_MUTEX
DECLARE_SEMA
MUTEX_CREATE


5. The value of the mutex when it is locked by a process is

0
1
-1
2


6. To create a semaphore which will attempt to get the lock only once, we can use the function

down()
down_tryonce()
down_trylock()
down_interrupt()


7. The functions down and down_interruptible work in similar fashion

True
False
Depends on kernel version
In case of mutex they are same


8. The function call to release a semaphore is

up
up_trylock
up_interruptible
All of the above


9. A reader writer semaphore allows

Multiple readers or only one writer
Multiple writers or only one reader
Multiple readers and writers
Only one reader or writer


10. Sending a signal from one thread to other regarding completion of a task/job can be done optimally

Mutex
Semaphore
Completion
None of the above

Answers : Answers to Linux Quiz on semaphores