Normal users can chmod files to make them unaccessible like
evgeniy@ubuntu:~$ touch test
evgeniy@ubuntu:~$ chmod 444 test
evgeniy@ubuntu:~$ echo 'test' > test
bash: test: Permission denied
Can something like this be simulated for the root user?
The problem doesn't occur very often, but still it surely exists and I'm not sure where to start from. I have grepped for the mongrel PIDs in /var/log/ and the only messages that contained them are these:
Jun 7 07:46:24 staging kernel: 4gb seg fixup, process mongrel_rails (pid 29498), cs:ip 73:00937a5c
It has something to do with Xen specific version of libc, but it's not critical, and the processes are still running with these messages accumulating in kern.log
I'm actually looking not only for specific solution (which probably couldn't be provided from the above description) but for any advice on how to set up monitoring or investigate such cases.