Re: PR/45909: Use of MIDI over USB interfaces crashes NetBSD

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR kern/45909; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost, 
netbsd-bugs%NetBSD.org@localhost,
        tih%hamartun.priv.no@localhost
Subject: Re: PR/45909: Use of MIDI over USB interfaces crashes NetBSD
Date: Sat, 4 Feb 2012 17:36:27 +0100

 On Sat, Feb 04, 2012 at 02:50:04PM +0000, Tom Ivar Helbekkmo wrote:
 >  Yeah, I don't understand that bit at all.  You get a KASSERT failure if
 >  you call usbd_abort_pipe() without holding the kernel lock, though - and
 >  another one if you *are* holding the thread lock, when it tries to do a
 >  context change with a mutex held.  This challenges my understanding of
 >  what the kernel lock is.  :)
 
 the kernel lock is much more than a simple mutex (there's a refcount so
 it can be reentrant, for example). When the kernel is going to sleep,
 the kernel lock is released and reaquired on wakeup.
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --