如何查看对内核模块所做的更改

Question

I am New to Linux kernel , I have Module running on my Linux Machine and can see it using lsmod command ,Now I made some changes(added some printk) to this moudule ,recompiled it and got the .ko .Now I did rmmod to remove this module(some other modules also which are using this module) and did insmod xxx.ko and reboot the system .

Now where Do I see the statements added using printk ,I tried to see using

dmesg grep | "SPI RW"

But couldn't find anything .Could anybody let me know what I am doing wrong here??

Answer 1

Try vim /var/log/messages or open messages in text editor verify

For enabling /var/log/messages

edit file /etc/rsyslog.d/50-default.conf

Change the following paragraph:

...
#
# Some "catch-all" log files.
#
#*.=debug;\
#       auth,authpriv.none;\
#       news.none;mail.none     -/var/log/debug
#*.=info;*.=notice;*.=warn;\
#       auth,authpriv.none;\
#       cron,daemon.none;\
#       mail,news.none          -/var/log/messages
.... 

to following: ...

#
# Some "catch-all" log files.
#
*.=debug;\
        auth,authpriv.none;\
        news.none;mail.none     -/var/log/debug
*.=info;*.=notice;*.=warn;\
        auth,authpriv.none;\
        cron,daemon.none;\
        mail,news.none          -/var/log/messages
...

and do restart rsyslog