Re: kern/46737 ucom (at least at uplcom) unusable under current SMP

[Michael van Elst <mlelstv%serpens.de@localhost>]

The following reply was made to PR kern/46737; it has been noted by GNATS.

From: Michael van Elst <mlelstv%serpens.de@localhost>
To: gnats-bugs%gnats.netbsd.org@localhost
Cc: 
Subject: Re: kern/46737 ucom (at least at uplcom) unusable under current SMP
Date: Mon, 1 Oct 2012 21:12:50 +0200

 When ttread was modified to use mutexes instead of spltty(), the locking
 was converted almost one to one.
 
 This left the getc() call in ttread() without locking as the clist
 functions are only protected by spltty(). This is not sufficient
 in a SMP environment.
 
 I have commited a patch to tty.c that keeps the mutex around the getc()
 loop and that seems to fix the problem for me.
 
 A pullup to -6 (or maybe even -5?) might be wanted.
 
 
 Greetings,
 -- 
                                 Michael van Elst
 Internet: mlelstv%serpens.de@localhost
                                 "A potential Snark may lurk in every tree."