From owner-freebsd-current Sun Mar 2 9:49: 8 2003 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4D29637B401 for ; Sun, 2 Mar 2003 09:49:07 -0800 (PST) Received: from heron.mail.pas.earthlink.net (heron.mail.pas.earthlink.net [207.217.120.189]) by mx1.FreeBSD.org (Postfix) with ESMTP id BE16E43FB1 for ; Sun, 2 Mar 2003 09:49:06 -0800 (PST) (envelope-from tlambert2@mindspring.com) Received: from pool0246.cvx22-bradley.dialup.earthlink.net ([209.179.198.246] helo=mindspring.com) by heron.mail.pas.earthlink.net with asmtp (SSLv3:RC4-MD5:128) (Exim 3.33 #1) id 18pXa6-00028O-00; Sun, 02 Mar 2003 09:48:59 -0800 Message-ID: <3E6243BB.282E436A@mindspring.com> Date: Sun, 02 Mar 2003 09:47:39 -0800 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Christoph Kukulies Cc: freebsd-current@freebsd.org Subject: Re: mgetty in ttys hoses system References: <200303021037.LAA30904@accms33.physik.rwth-aachen.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-ELNK-Trace: b1a02af9316fbb217a47c185c03b154d40683398e744b8a4dbd8cf97b6f6bedfcfdfd800b804af7b350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Christoph Kukulies wrote: > I installed the /usr/ports/comms/mgetty+sendfax to get my > new servers functions completed and found after installing the > port and giving a kill -HUP 1 - the port adds the > line > cuaa0 "/usr/local/sbin/mgetty" unknown on insecure > to /etc/ttys. > > After that the system was hosed. After rebooting > the system seemed to got hung in multi user mode. > No vtys and I booted into single user. > > Found that /etc/ttys contained passwd entries instead, totally > hosed. It never happended to me that I got FS corruption > like this before. This is a well-known FreeBSD VM bug, having to do with writes to COW pages for objects mapped read-only. It happens when you modify the contents of the data areas returned by getpwent(). We had the same problem with Vixie "cron" on the InterJet; it would spam the crontab with a page of data from the passwd database. No one ever fixed it, because no one after Dyson has really bothered to fully understand the VM system, before making changes to it. You can work around it by modifying the program to copy the pwent contents (or use it's own pwent structure) instead of modifying the returned data areas. This avoids triggering the COW, where the dirty buffer gets attached to the wrong vnode. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message