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To: Ciro <domino@asgardnet.org>
In-Reply-To: Your message of "Tue, 20 May 2003 04:00:15 EDT."
             <20030520035715.Q18906-100000@aegir.asgardnet.org> 
Date: Tue, 20 May 2003 10:17:51 +0100
From: Ian Dowse <iedowse@maths.tcd.ie>
Message-ID: <200305201017.aa40105@salmon.maths.tcd.ie>
cc: freebsd-questions@freebsd.org
Subject: Re: Strange log message in daily security run? 
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In message <20030520035715.Q18906-100000@aegir.asgardnet.org>, Ciro writes:
>Every now and again I'll get the following mess in my nightly security
>run email. Is it a bug, bit-rot, or some kind of attack, or none of the
>above? Has Anyone run into this mess before?
>
>aegir.asgardnet.org kernel log messages:
..
>^H\^P \^P\^D\^B@\^H\^H\^D \^P\^A \^A@\^B\^H(\^D\^B\M^@\M^@\^P\^B\^H\
>^A\^BCopiright (c) 1992m2002 The FreeB\^SF PrO*ect.

Does it just occur within a day or two of a reboot? If so it's
nothing to worry about. This can happen if the system memory is not
cleared by the BIOS and can get corrupted while rebooting (the
memory contents rot away while the DRAM refresh mechanism is
disabled).

When FreeBSD boots up, it sees what it thinks is an intact message
buffer, so it decides not to clear it (sometimes panic messages
before a reboot survive, so this can be very useful). The problem
has been fixed in -CURRENT by adding a checksum to the message
buffer.

Ian