re: kern/41715

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

The following reply was made to PR kern/41715; it has been noted by GNATS.

From: matthew green <mrg%eterna.com.au@localhost>
To: 
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
    netbsd-bugs%netbsd.org@localhost, Thomas Klausner 
<wiz%NetBSD.org@localhost>,
    gnats-bugs%NetBSD.org@localhost
Subject: re: kern/41715
Date: Mon, 03 Aug 2009 16:40:41 +1000

    
    there is a problem with the vblank callout firing while the
    drm is being torn down.  i'm not entirely sure what the
    sequence is, but the crash occurs in radeon_get_vblank_counter
    when it is called from the callout, not from the close.
 
 this is right.
    
    i don't think drm_lastclose() is being called.
    
 this isn't right.
 
 the problem occurs because drm_vblank_cleanup() is called in
 drm_unload() and not by drm_lastclose().  that leaves callouts
 maybe pending, and if they fire they'll act on unmapped space.
 
 i haven't figured out the right fix yet.  just the simple
 rearrangement of code doesn't seem to work properly, though i
 am avoiding the panic.
 
 
 .mrg.