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

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

The following reply was made to PR kern/50430; it has been noted by GNATS.

From: matthew green <mrg%eterna.com.au@localhost>
To: paul%whooppee.com@localhost
Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost,
    gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
    Christos Zoulas <christos%zoulas.com@localhost>
Subject: re: kern/50430: syscall_disestablish() can remove active syscalls
Date: Mon, 16 Nov 2015 09:22:46 +1100

 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.