Embedded Linux Development Using Yocto Project Cookbook - Second Edition

How to do it...

The debugfs interface adds probes via the /sys/kernel/debug/tracing/kprobe_events file.

For example, to add a kprobe called example_probe to the do_sys_open function, you can execute the following command:

# echo 'p:example_probe do_sys_open dfd=%r0 filename=%r1 flags=%r2 mode=%r3' > /sys/kernel/debug/tracing/kprobe_events 

The probe will print the function's argument list, according to the function's declaration arguments as seen in the function's definition as follows:

long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode);  

You can then manage kprobes through the sysfs as follows:

• To see all the registered probes:

# cat /sys/kernel/debug/tracing/kprobe_events
p:kprobes/example_probe do_sys_open ...