Re: [PATCH V2 4/8] mm/highmem: Add VM_BUG_ON() to mem*_page() calls

[Ira Weiny]

On Wed, Feb 10, 2021 at 12:55:02PM +0000, Christoph Hellwig wrote:
> On Tue, Feb 09, 2021 at 10:22:17PM -0800, ira.weiny@xxxxxxxxx wrote:
> > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> > 
> > Add VM_BUG_ON bounds checks to ensure the newly lifted and created page
> > memory operations do not result in corrupted data in neighbor pages and
> > to make them consistent with zero_user().[1][2]
> 
> s/VM_BUG_ON/BUG_ON/g ?

Andrew wanted VM_BUG_ON.[1]

And I thought it was a good idea.  Any file system development should have
tests with DEBUG_VM which should cover Matthew's concern while not having the
overhead in production.  Seemed like a decent compromise?

Ira

[1] https://lore.kernel.org/lkml/20210209131103.b46e80db675fec8bec8d2ad1@xxxxxxxxxxxxxxxxxxxx/

> 
> Otherwise looks good:
> 
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>