Re: [PATCH] permission hook in filemap_nopage

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Valdis.Kletnieksat_private

On Mon, 04 Feb 2002 16:43:11 PST, Chris Wright said:

> the open(2), mmap(2) code path is protected.  so reading from a maped
> file is protected, albeit revocation _is_ challenging.  have you

Also challenging for the *application* programmer.  'man 2 mmap' lists
only these errors under using a sucessfully mmap-ed region:

       SIGSEGV
              Attempted write into a region specified to mmap  as
              read-only.

       SIGBUS Attempted  access  to  a portion of the buffer that
              does not  correspond  to  the  file  (for  example,
              beyond  the  end  of  the  file, including the case
              where another process has truncated the file).

What error would you return to a userspace program if the mmap'ed
region had been revoked by the kernel?  Throw an undocumented SIGSEGV
or SIGBUS, or do something else?

-- 
				Valdis Kletnieks
				Computer Systems Senior Engineer
				Virginia Tech