Re: Suspicious code in i2c-dev.c

From: Jens Axboe (axboe@suse.de)
Date: Sun Jan 23 2000 - 17:10:44 EST


On Sun, Jan 23 2000, Frodo Looijaard wrote:
> > 2. copy_to_user may fault, and if this is the case, the user will
> > never know (the user will not see the EFAULT error code returned).
>
> > There are more instances of point 2, including some with copy_from_user.
>
> Hmm. Can you elaborate on that? What exactly will happen when a
> copy_{to,from}_user faults? And what does a fault in this instance
> mean (cache miss?).

It means that copy_[to|from]_user tried to access memory that didn't
belong in the current process address space. In this case they
will return non-0 and -EFAULT should be returned to the process.

-- 
*  Jens Axboe <axboe@suse.de>
*  Linux CD-ROM Maintainer
*  http://www.kernel.dk

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