Class Exercise 2.2: Interrupt/Exception Handling Process

Level 1: Divide-by-zero exception analysis

input the command

cp /data/workspace/myshixun/exp1/1.1.tgz ~/os
cd ~/os/linux-0.11-lab
tar -zxvf ../1.1.tgz 1.1
rm -rf cur
ln -s 1.1 cur
cd 1.1/linux
make

Open another terminal

cd ~/os/linux-0.11-lab
./rungdb

Enter in the original terminal

cd ../..
./mygdb

debug gdb input

b main.c:147
c
x/6i $eip
si
si
si
info registers
si
info registers

Terminal picture after debugging

Finally remember to kill to exit gdb. Prevent it from affecting the next level

1. In the assembly instruction fragment corresponding to the statement "jiffies =jiffies/0;" in function main, there is an idiv instruction. What is the address of this instruction? (0x0000690e) 2. Before the idiv instruction is executed, the current instruction
position What are (CS:EIP) and stack position (SS:ESP) respectively? (0xf:0x690e) and (0x17:0x25760)
3. After executing the instruction using the si command, what are the new instruction position and stack position respectively? ( 0x8:0x814b) and (0x10:0x1fa2c)
4. What are the recovery point positions and user stack positions saved in the stack at this time? (0xf:0x690e) and (0x17:0x25760)

Level 2: int instruction analysis

Environmental preparation

cp /data/workspace/myshixun/exp2/1.tgz ~/os
cd ~/os/linux-0.11-lab
tar -zxvf ../1.tgz 1
rm -rf cur
ln -s 1 cur
cd 1/linux
make

 Enter the gdb debugging input (see the previous level for gdb debugging)

b task1
c
x/5i $eip
si
x/5i $eip
info registers
si
info registers
x/5wx $esp

 

Level 3: iret instruction analysis

In the second level environment, debug gdb and enter

b task1
c
x/5i $eip
si
x/5i $eip
info registers
si

bt
disas
b *0x795e
c
x/5i $eip
info registers
x/5wx $esp
si
info registers