Re: [RFC] prevent "dd if=/dev/mem" crash

From: Pavel Machek <>
Date: 2003-10-20 04:17:57

> > Old behavior:
> > 
> >     # dd if=/dev/mem of=/dev/null
> >     <unrecoverable machine check>
> I recently fixed this for ia32 by changing copy_to_user() to not oops if
> the source address generated a fault.  Similarly copy_from_user() returns
> an error if the destination generates a fault.

Are you sure this is not hiding real errors? If you pass wrong
kernel ptr to copy_*_user, it should oops, not mask error with
Maybe another copy_user_unsafe should be created?
Written on sharp zaurus, because my Velo1 broke. If you have Velo you don't need...

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Received on Thu Oct 23 04:12:59 2003

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