Re: [Fwd: Re: kern/118258 sysctl causing panics on 7.0-xxx]

On Friday 04 January 2008 05:19:28 am Tai-hwa Liang wrote:
> On Thu, 3 Jan 2008, John Baldwin wrote:
> > On Thursday 29 November 2007 10:53:32 pm Tai-hwa Liang wrote:
> >> On Wed, 28 Nov 2007, Remko Lodder wrote:
> >>> Hello,
> >>>
> >>> So as per Jeff's information, can someone from the -current
> >>> list either contact jeff or try to resolve the problems
> >>> mentioned? :)
> >>
> >>    This is a longstanding bug which also exists in RELENG_6.  It turns 
out
> >> that 'sysctl kern.ttys' after a terminal device is removed could trigger
> >> this panic reliably.  For example, do 'sysctl kern.ttys' multiple times
> >> after detaching an USB serial-to-rs232 cable or a PCMCIA modem card.
> >>
> >>    Alternatively, following script would demo the panic if you don't have
> >> a physically removable terminal device:
> >>
> >> #!/bin/sh
> >> #
> >> # Warning! Running this script as root will panic your CURRENT box...
> >> #
> >> while true; do
> >>  	kldload dcons
> >>  	kldunload dcons
> >>  	ls /dev
> >>  	sysctl kern.ttys
> >>  	sleep 1
> >> done
> >>
> >>    This seems to be a race between devfs and destroy_dev(), Cc'ing kib_at_
> >> since he probably has more clues in this area.
> >
> > Try this patch.  Also available at
> > http://www.FreeBSD.org/~jhb/patches/ttys_sysctl.patch
> 
>    With this patch, -CURRENT no longer boots and panics as follows:

Fixed, was missing an unlock at the bottom of the loop.  Patch is updated at 
the same URL.

-- 
John Baldwin