monerod crashes with segmentation fault when MemoryDenyWriteExecute=yes is enabled in systemd unit (ARM/Raspberry Pi)

[jtrinh27]

Version: Monero 'Fluorine Fermi' (v0.18.4.3-release)

When running monerod on Raspberry Pi 5 (ARM64) with a hardened systemd unit, enabling MemoryDenyWriteExecute=yes causes the daemon to crash immediately after startup. Disabling this directive allows monerod to run normally.

journalctl log excerpt:

systemd[1]: Started Monero Daemon.
monerod[1234]: 2025-10-27 12:34:57.123        I SYNCHRONIZATION started
systemd[1]: monerod.service: Main process exited, code=killed, status=11/SEGV
systemd[1]: monerod.service: Failed with result 'signal'.
systemd[1]: monerod.service: Scheduled restart job, restart counter is at 3.
systemd[1]: Started Monero Daemon.

Minimal monerod.service file to reproduce:

[Unit]
Description=Monero Daemon
After=network-online.target

[Service]
User=monerod
Group=monerod
ExecStart=/usr/local/bin/monerod --non-interactive --config-file=/etc/monerod.conf
Restart=on-failure
RestartSec=5s
WorkingDirectory=/srv/monero-data
MemoryDenyWriteExecute=yes

[Install]
WantedBy=multi-user.target

I'm not sure why MemoryDenyWriteExecute=yes causes monerod to crash, but I'd appreciate clarification. Is this related to JIT, cryptographic operations, or another technical requirement? I understand this directive is intended for security hardening, but would like to know why Monero needs executable memory mappings.

[jeffro256]

If I had to guess, it's probably the RandomX JIT compiler. Was it mining? IIRC, W+X should only be enabled on mining threads. You can try running the binary with environment variable MONERO_RANDOMX_UMASK=16 and see if that helps.

[jtrinh27]

Thanks for the clarification! Based on my configuration, monerod is not mining. The configuration runs monerod as a full node.

[techmetx11]

If I had to guess, it's probably the RandomX JIT compiler. Was it mining? IIRC, W+X should only be enabled on mining threads. You can try running the binary with environment variable MONERO_RANDOMX_UMASK=16 and see if that helps.

I think RandomX may have JIT optimizations on by default regardless if it's mining or not

[jtrinh27]

I appreciate the response. Any idea if it can be turned off in anyway while not mining?

[techmetx11]

I appreciate the response. Any idea if it can be turned off in anyway while not mining?

Try running monerod with the env variable that @jeffro256 gave. This will unfortunately slow down RandomX computation significantly but may work