Past MCQ/Short Response Qs

Question 1

In the following code the address printed by printf belongs to which section?

int *p;
p = malloc(sizeof(int));
printf(“&p=%p\n”, &p);

Answer 1

Stack

Question 2

Question on insertion to freelist based on malloc implementation.

Answer 2

Check gradescope to see Q.

Question 3

Question on insertion to freelist based on malloc implementation.

Answer 3

Check gradescope to see Q.

Question 4

Q4 review

Question 5

Which assertions are true about the following code?

char * p = (int *) malloc(10);
strcpy(p, “123456789012345”);
free(p);

I. This is an example of memory smashing
II. This is a bug but the program will not crash.
III. This is an example of a wild free.
IV. The program may crash in line 3

Answer 5

I and IV.

Question 6

What is the initial value of the reference count of an i-node of a directory and why?

Answer 6

It is 2, one for entry in the parent and one that refers to the current directory.

Question 7

What will this do?

int fd = open(“outfile”, O_RDWR);
if (fork()) {
dup2(fd, 1);
}
else {
write(1, “hello\n”, 6);
}

Answer 7

It sometimes prints “hello\n” to the outfile and sometimes to the terminal

Question 8

Can a free object be next to another free object in the heap?

Answer 8

No, they would have been coalesced.

Question 9

Q9 review

Question 10

What gbd command shows where a segv happened?

Answer 10

where