Re: ufs: add ioctl interface for query request

[Dan Carpenter <dan.carpenter@oracle.com>]

On Mon, Apr 13, 2015 at 10:55:58AM -0000, Gilad Broner wrote:
> > copy_to/from_user() returns the number of bytes not copied and not an
> > error code.  Printing these error messages in the ioctl means the user
> > can trigger a DoS by filling up /var/log/messages.  They make the code
> > uglier.  We should stop here if the copy fails and goto out_release_mem
> > otherwise we might end up returning success by mistake.
> 
> Thanks for the comment, I will update the code.
> I wanted to clarify about the possibility of a DoS attack:
> - Isn't var/log/messages cyclic or size limited in some way?

Some people limit it some people don't.  To be honest, I'm not really
concerned about this, but I use it as an excuse to remove debug
messages.

> - What determines that dev_err() prints go to /var/log/messages?
>   would it still be the case if dev_dbg() was used instead?

Normally dev_dbg() message are not printed.  But just remove them.  They
make the code uglier.

regards,
dan carpenter