Subject: Re: problem with DMA driver (vm race?)
To: Matthias Drochner <firstname.lastname@example.org>
From: Jason Thorpe <email@example.com>
Date: 06/24/1996 10:39:22
On Mon, 24 Jun 1996 16:39:23 +0200 (MET DST)
Matthias Drochner <firstname.lastname@example.org> wrote:
> If the machine is heavily loaded (esp. process creation) the
> "vsunlock()" occasionaly causes a panic in "vm_fault_unwire()":
> "unwire: page not in pmap". The reason is (I checked it explicitely
> before calling "vsunlock()") that the page directory entry for
> the user buffer became zero in the meantime.
> (The check tests
> vm_map_pmap(&curproc->p_vmspace->vm_map)->pm_pdir[((vm_offset_t)(buf) >>
> The system is NetBSD-1.1.
> Can anybody explain this?
Paul Kranenburg recently dealt with some race conditions in this area.
You might consider upgrading your system to -current (which is currently
following the 1.2 release sources).
-- save the ancient forests - http://www.bayarea.net/~thorpej/forest/ --
Jason R. Thorpe email@example.com
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