improve seccomp load failure error message

[Chad Miller]

systemd[1]: Started Service for snap application tor-middle-relay.daemon.
ubuntu-core-launcher[21741]: seccomp_load failed with -22
ubuntu-core-launcher[21741]: aborting. errmsg: Invalid argument
systemd[1]: snap.tor-middle-relay.daemon.service: Main process exited, code=exited, status=1/FAILURE
systemd[1]: snap.tor-middle-relay.daemon.service: Unit entered failed state.
systemd[1]: snap.tor-middle-relay.daemon.service: Failed with result 'exit-code'.
systemd[1]: snap.tor-middle-relay.daemon.service: Service hold-off time over, scheduling restart.
systemd[1]: Stopped Service for snap application tor-middle-relay.daemon.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: snapd 2.0.9
ProcVersionSignature: Ubuntu 3.2.0-1412.16-omap4 3.2.14
Uname: Linux 3.2.0-1412-omap4 armv7l
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: armhf
Date: Tue Jun 21 23:27:26 2016
SourcePackage: snapd
UpgradeStatus: Upgraded to xenial on 2016-05-11 (42 days ago)

[Chad Miller (cmiller)]

$ snappy-debug.security
seccomp_load failed with -22
aborting. errmsg: Invalid argument

[Chad Miller (cmiller)]

This may be that some functionality isn't in the kernel in this snappy-on-classic machine (Pandaboard hardware).

If so, the bug in snappy is that the error message is completely useless.

[Jamie Strandboge (jdstrand)]

ubuntu-core-launcher[21741]: seccomp_load failed with -22 does seem to indicate that the kernel may not have seccomp configured. I suggest looking at https://github.com/leannogasawara/sample-kernels to confirm you have everything needed (note, AIUI that page is temporary and will be incorporated somewhere more official).

[Jamie Strandboge (jdstrand)]

Moving to ubuntu-core-launcher for the error message.