In answer to My process was killed but I cannot understand the kernel notice, I was pointed to some documentation on the Secure Attention Key (SAK) on Linux. I have a embedded system generated using buildroot which uses busybox and the busybox init system. I am unable to find either rc.local or rc.sysinit on my system anywhere. I have looked online but I cannot find any documentation (other than the link above) that tells how I can identify what the SAK is for my system. Can anyone tell me how I can get this information and also if I can turn the SAK off? As my system is embedded and isolated from the internet I am not overly concerned with security breaches or hack attempts. The SAK seems to pop up out of nowhere and kills my main embedded application which is totally unacceptable so if I can turn this off it would be better for my needs (even if this means I have to reconfigure and build my kernel)

1 Answer 1


According to this mailing list post SAK is «break», k. So you could be receiving it over the serial port. The kernel sysrq documentation agrees.

That kernel document also gives a solution: disable sysrq by echo 0 >/proc/sys/kernel/sysrq. Or, alternatively, only enable the ones you'd like.

You can also configure SAK using setserial, according to the setserial man page.

Busybox init probably runs the /etc/init.d/rcS shell script. It also runs other things out of /etc/inittab. I suggest looking at that shell script see where you should plop scripts to set these things.

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