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xenithorb/rpi_enable_watchdog.sh

Last active February 23, 2017 04:23
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One-liner to enable Rasbperry Pi 3 watchdog timer
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rpi_enable_watchdog.sh
if [[ -c /dev/watchdog ]]; then if [[ -d /etc/systemd ]]; then mkdir /etc/systemd/system.conf.d &>/dev/null; else { echo "ERROR: No systemd"; exit; }; fi; echo -e "[Manager]\nRuntimeWatchdogSec=10\nShutdownWatchdogSec=3min" > /etc/systemd/system.conf.d/watchdog.conf; else { echo "No watchdog device present"; exit; }; fi && systemctl daemon-reload && systemctl daemon-reexec && systemctl show | grep Watchdog
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xenithorb commented Feb 23, 2017 •
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After it's enabled you can test with a bash or perl forkbomb:

# DO NOT RUN THIS IT WILL CRASH YOUR SYSTEM
:(){ :|:& };:

# Or perl:
perl -e "fork while fork" &

The system at some point should reboot when the watchdog can no longer be contacted for 5 seconds

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xenithorb commented Feb 23, 2017 •
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On some tests it took about 4 minutes from the start of the fork bomb as a normal user to hang the system ( this seems to go much quicker as root as I assume due to the fact of not having limits as root. )

Once the system became totally unresponsive to ping it was unreachable for 11 seconds, and came back up immediately. It then showed an uptime of 0min confirming that a reboot occurred.

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