Dynamic Kernel Debugging

0. Compile kernel with CONFIG_DYNAMIC_DEBUG=y

1. Mount debugfs, if not mounted yet

    sudo mount -t debugfs none /sys/kernel/debug
   

2. Turn on debug for a specific module

    echo 'module pblk +pfl' > /sys/kernel/debug/dynamic_debug/control
   

The flags are:

	p    enables the pr_debug() callsite.
	f    Include the function name in the printed message
	l    Include line number in the printed message
	m    Include module name in the printed message
	t    Include thread ID in messages not generated from interrupt context
	_    No flags are set. (Or'd with others on input)