Re: [PATCH] iio: core: WARN in case sample bits do not fit storage bits

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Mon, Mar 21, 2022 at 03:46:51PM +0100, Marek Vasut wrote:
> On 3/21/22 11:40, Andy Shevchenko wrote:
> > On Sun, Mar 20, 2022 at 07:15:42PM +0100, Marek Vasut wrote:
> > > Add runtime check to verify whether storagebits are at least as big
> > > as shifted realbits. This should help spot broken drivers which may
> > > set realbits + shift above storagebits.
> > 
> > Thanks!
> > 
> > ...
> > 
> > > +			/* Verify that sample bits fit into storage */
> > > +			WARN_ON(channels[i].scan_type.storagebits <
> > > +				channels[i].scan_type.realbits +
> > > +				channels[i].scan_type.shift);
> > 
> > Not sure WARN is a good level (it might be fatal on some setups and we won't that),
> > besides the fact that we may use dev_WARN(). Perhaps dev_warn() would suffice?
> 
> I was actually thinking about BUG(), but that might crash existing systems.
> I think we want a strong indicator that something wrong is going on which
> must be fixed and the splat produced by WARN_ON() is a good indicator of
> that. It also does not crash existing systems,

It does crash _some_ of them, unfortunately.

> so even if existing users get
> a warning now, they won't get an unbootable system and can report that
> warning.

-- 
With Best Regards,
Andy Shevchenko