On Mon, Dec 23, 2013 at 11:42:22AM -0700, Matthew Wilcox wrote:

quoted

Do you know anyone who relay on SIGBUS for correctness?

Oh, I remember the real reason now.  If we install a PMD that hangs off
the end of the file then by reading past i_size, we can read the blocks of
whatever happens to be in storage after the end of the file, which could
be another file's data.  This doesn't happen for the PTE case because the
existing code only works for filesystems with a block size == PAGE_SIZE.

I see. It's valid reason. Probably, it's better to add comment there.

-- 
 Kirill A. Shutemov