re: kern/50430: syscall_disestablish() can remove active syscalls

[matthew green <mrg%eterna.com.au@localhost>]

Paul Goyette writes:
> On Sun, 15 Nov 2015, Christos Zoulas wrote:
> 
> > Sure, that sounds prudent. ...
> 
> Also realize that disabling autounload won't prevent manual unloading
> of modules via modunload(8).

we also don't prevent root from modloading a call to panic() ;)

> It's not only "compat" modules that need to worry about this.  It is
> potentially any unloadable module that uses syscall_establish().  (We
> could skip allocating/setting the flag for built-in modules, but I
> don't think that syscall_establish() is aware of this.)

yup.  this problem is pretty severe and i'm quite amazed we've
not noticed problems from it way more often.

thanks.


.mrg.