Debugging

When we have source code

• GDB Tutorial
• Pro .gdbinit

Don't forget the nice hexdump macros. Write python scripts for parsing buffer content (when debugging a serial protocol).

We don't have source code, ask the OS

• strace - What problems do people solve with strace, don't forget to filter with -e
• logger - just print events from different processes eg. init scripts
• stress - thermal issues, race conditions, io load, latency

Latency, from a general point of view, is a time delay between the cause and the effect of some physical change in the system being observed. - wiki

• lsof - file descriptor leak
• LD_PRELOAD

We don't have source code, look at the binary

• readelf

When we debug the OS

Add some prints:

dev_info(&pdev->dev, "Why are we here? \n");

now dmesg

Catching device events:

• cat /proc/interrupts
• udevadm info -a -n /dev/sda | less

The /sys:

• get some device info
• control devices - pwm

Attach debugger: