Date: Thu, 8 Feb 1996 19:38:03 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: wollman@freefall.freebsd.org (Garrett Wollman) Cc: fredriks@mcs.com, wollman@freefall.freebsd.org, freebsd-bugs@freefall.freebsd.org Subject: Re: kern/383 Message-ID: <199602081838.TAA29988@labinfo.iet.unipi.it> In-Reply-To: <199602081659.IAA01134@freefall.freebsd.org> from "Garrett Wollman" at Feb 8, 96 08:59:37 am
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> Synopsis: dd to from /dev/mem panics the machine. > > State-Changed-From-To: open-closed > State-Changed-By: wollman > State-Changed-When: Thu Feb 8 08:58:24 PST 1996 > State-Changed-Why: > It is an error to dd from random regions of /dev/mem. All > sorts of nasty things can happen. I have experienced a similar problem. It occurred when reading from /dev/mem with "dd" from within an xterm. The same thing from a vty worked fine, as it did a C program doing random reads from the whole memory space running from within an xterm. In my case I don't think the crashes were caused by underlying hw problems, otherwise they would only depend on the phys. address, not on the program that uses it or other context-dependant issues. And how can reads from phys. mem be harmful ? I would at least like to know why it crashes the system. Thanks Luigi
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