> 1 - I'm trying to implement a new kernel function in Minix OS 3.1.0 ,
> and when I invoke my function, sometimes it works fine, and other
> times I get the error:
> syscall: ipc mask denied 0 sending to 52
> syscall: ipc mask denied -2 sending to -5
>
> If anyone want more information, please tell me.
>
> What should be the problem?

Perhaps you're trying to call it directly from an application?

An ordinary process is not allowed to sendrec to the kernel, so you
cannot use kernel calls there. The proper (though not the only)
solution would be to also implement a call in FS or PM that wraps the
kernel call. Your program can then call the wrapper function.