Article View: comp.sources.bugs
Article #2068screen: Crashes the kernel!
From: Gregory N. Bond
Date: Thu, 16 Feb 1989 04:52
Date: Thu, 16 Feb 1989 04:52
36 lines
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2305 bytes
Environment: Sun 3/260, SunOs 3.5Export, Screen v 2.0a 19-oct-88
The screen program recently posted to comp.sources.unix uses unix
domain sockets to communicate. This latest version also has a feature
that allows you to detatch a login session and re-attatch it at
another terminal.
However, if you exit from screen by exiting the shells in turn,
rather than by using ^A^\, then there is a screen process left
running and connected to the socket $HOME/.screen/`hostname`.`tty`.
The next time you log in (I think it has to be straight away), you
get a message saying there is a screen program running, use "screen
-r" to reattach. If you the do a screen -r, it hangs. If you then
attempt to kill the screen, using ^\, the kernel panics with a kernel
mode bus error. This happens frequently (i.e. twice in 10 minutes of
my playing around), but not exactly every time. Naturally, as this is
a live system, I am loathe to do too much experimenting!
This appears to be the old berkeley "kill process in unix domain
accept" bug, about which I have heard. Can anyone point out the exact
circumstances this bug will bite, if it is known to exist in SunOs
3.5Export, and what the standard workaround is. I would DEARLY love to
hear from anyone who has fixed this bug, as some not-quite
sophisticated users are bound to find this bug one day!
BTW, I *LOVE* this program, and use it all the time. And the new
version is much more robust than the old version (1.1i), particularly
in the handling of complex curses-based programs (where the old
version lost characters and gave garbage screens after a few minutes
of heavy use).
Greg.
--
Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia
Internet: gnb@melba.bby.oz.au non-MX: gnb%melba.bby.oz@uunet.uu.net
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!apple!vsi1!wyse!uunet!munnari!murtoa.cs.mu.oz.au!wcc!latcs1!ditmela!yarra!melba!gnb From: gnb@melba.bby.oz (Gregory N. Bond) Newsgroups: comp.sources.bugs Subject: screen: Crashes the kernel! Message-ID: <105@melba.oz> Date: 16 Feb 89 04:52:59 GMT Organization: Burdett, Buckeridge & Young Ltd, Melbourne Lines: 36