Date: Thu, 17 Apr 1997 15:00:02 -0400 From: Chris Shenton <cshenton@it.hq.nasa.gov> To: bugs@freebsd.org Subject: Forward: Re: 2.2.1-R crash with looped serial gettys Message-ID: <199704171900.TAA04678@wirehead.it.hq.nasa.gov>
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----Next_Part(Thu_Apr_17_14:58:35_1997)-- Content-Type: Text/Plain; charset=us-ascii Bruce says I should have reported this here. Usually the failure is my fault, not FreeBSD's, so I hesitate to bother you folks first. Thanks. ----Next_Part(Thu_Apr_17_14:58:35_1997)-- Content-Type: Message/rfc822 Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19]) by apollo.it.hq.nasa.gov (8.8.3/8.8.3) with ESMTP id OAA22556 for <cshenton@it.hq.nasa.gov>; Thu, 17 Apr 1997 14:21:56 -0400 (EDT) Received: (from bde@localhost) by godzilla.zeta.org.au (8.8.5/8.6.9) id EAA09021; Fri, 18 Apr 1997 04:22:51 +1000 Date: Fri, 18 Apr 1997 04:22:51 +1000 From: Bruce Evans <bde@zeta.org.au> Message-Id: <199704171822.EAA09021@godzilla.zeta.org.au> To: cshenton@it.hq.nasa.gov, hackers@FreeBSD.ORG Subject: Re: 2.2.1-R crash with looped serial gettys >I've built a little box for pppd/mpd and routing out of a 486sx33 and >a whopping 8MB RAM; seems to mostly run fine with 2.2.1-RELEASE. It's >a fairly minimal install (Kernel User option I think) and I rebuilt >the kernel to fit the hardware. I've added a dual 16550A serial port >card to which I'll connect a pair of modems. I have getty running on >the ports, cuaa1 and cuaa2. > >PROBLEM: > >If I connect a null-modem cable between the ports, the system crashes >within a couple seconds. It's repeatable. > >It leaves no message in /var/log/messages, or dmesg, and there's no >core file. > >I presume looping the serial gettys is causing them to scream at each >other "Login:"; "Invalid Login:"; no *you* login; dammit, `login' is >not a valid login... and consumes too many resources. 4 problems: 1. Yes there is a getty war (actually probably a login war) that consumes too many resources (at 115200 bps, about 100% of a 486/33 for echoing and receiving echoes alone according to my estimates. On a 486SX/33 it is unlikely that the system runs any cycles in user mode once the war starts. 57600 bps might work). 2. There is a timeout leak in siopoll(). Oops. This causes a panic instead of a hang. With this fixed, the hang is fixable by unplugging the cable. 3. You should have seen a panic message about (2). 4. This problem should have been reported to freebsd-bugs :-). Bruce ----Next_Part(Thu_Apr_17_14:58:35_1997)----
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