> What you're describing should work correctly (it's part of the
> regression test suite we use). So, given that, I'd love to get to the
> bottom of what you're seeing. Do you have a URL to your code? What
> architecture are you running on?

Well, I must be doing something wrong then.
I extracted a test case from my program.
I put it on http://ptrace.fefe.de/seccompfail.c

It installs three seccomp filters, the last one containing this:

    DISALLOW_SYSCALL(prctl),

with

#define DISALLOW_SYSCALL(name) \
	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
	BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)

It is my understanding that that should then kill the process if the
prctl syscall is called again.

I test this by attempting to install the very same seccomp filter again,
which calls prctl, but the process is not killed.

What am I doing wrong?

Thanks,
Felix