On Fri, 4 Jan 2008, John Baldwin wrote: > 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. This one works like a charm! I've tried with USB-to-RS232 cable as well as aforementioned script. Now -CURRENT wouldn't panic by dumping kern.ttys. Great work! -- Thanks, Tai-hwa LiangReceived on Tue Jan 08 2008 - 02:51:03 UTC
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