If shutdown is called through sysrq-trigger, It travels through kernel/reboot.c and reports "reboot: Power down" root@tegra-ubuntu:~# echo o [96231.985333] therm_fan_est_work_func, cur_temp:35000, cur_trip_index:1 root@tegra-ubuntu:~# uname -a Linux tegra-ubuntu 3.10.67-g5c14da1 #1 SMP PREEMPT Tue Jun 9 19:03:35 PDT 2015 aarch64 aarch64 aarch64 GNU/Linux root@tegra-ubuntu:~# echo o > /proc/sysrq-trigger [96242.604487] SysRq : Power Off [96242.607479] nvdumper: rebooting cleanly. [96242.611398] nvdumper: set_dirty_state 0xf000caf3 root@tegra-ubuntu:~# [96242.619115] jsa1127 0-0039: jsa_enable [96242.642594] therm-fan-est: shutting down [96242.666497] gk20a gpu.0: shutting down [96242.670375] late_shutdown started [96242.706669] Shutting down tegra ... [96242.710155] reboot: Power down [96242.713306] max77620-power-off max77620-power-off.4: Powering off system Actually, there is no need to tag "reboot:" anywhere, as the message to be provided is the reason for reboot/shutdown through pr_emrg, but not from which file it was caused. root@sborra:/media/LinxA/linux-3.10.67/kernel# cat reboot.c | grep -n "reboot:" 7:#define pr_fmt(fmt) "reboot: " fmt Finally, "reboot:" tag should be removed.
"Reboot: Power down" is an oxymoron On an x86 machine, without any UART logs generated, this kernel log message doesn't appear, but on an Embedded system, this appears on debug/UART logs, and is not clear of the happened event, "Reboot" OR "Power down"