I have recompiled the Linux kernel on Ubuntu and now upgraded to 4.17.6. I need to modify the TCP/IP stack parts, in specific one of the congestion control algorithms (eg. Vegas). After successful recompilation to 4.17.6, I tried to modify the code and only recompile relevant modules but can’t see any messages on the
dmesg. I followed the following steps to test whether the
pr_debug works but none of them worked.
#define DEBUG on top of the modified files, then I added the following lines into desired functions
printk(KERN_DEBUG "test:"); printk("test:"); pr_debug("test:");
I ran the following commands:
sudo make -j8 net sudo make -j8 M=net sudo make -j8 modules SUBDIRS=net sudo make -j8 modules_install SUBDIRS=net sudo reboot
After reboot I modified
printk file to show all message levels by executing
echo 8 | sudo dd of=/proc/sys/kernel/printk. Then tried pinging from VM and to the VM and tried opening webpages. Then, tried to see message by running
dmesg | grep test:
But no messages are shown, where is the problem?