Sometimes it's useful to get more information from the Kernel:
Logging
# Turn up kernel logging $ sudo dmesg -n 7 $ cat /proc/sys/kernel/printk 7 4 1 7
Stack Traces
Apr 20 10:36:55 rd4 kernel: [23249.017661] sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(V) show-blocked-tasks(w) dump-ftrace-buffer(z) # Show stack traces for all CPUs $ echo l > /proc/sysrq-trigger # show task states $ echo t > /proc/sysrq-trigger