What's wrong on this mmap() ?

Gasparini Andrea gaspa at yattaweb.it
Fri Sep 23 11:22:12 EDT 2011


On Fri, Sep 23, 2011 at 1:50 PM, Andrea Gasparini <gaspa at yattaweb.it> wrote:
> Hi,
> I'm having some problem understanding how mmap really works.
> I have a (dummy) driver that allocate some memory (4k), and gives it to a
> userspace through mmap() - the usual remap_pfn_pages found in every
> example.
> The userspace can read the memory correctly, but can't write to it. (though
> it maps with PROT_WRITE)
> As the manpage says: PROT_WRITE - Pages may be written.

Aerhm. If opened with  O_RDRW and mapped with MAP_SHARED it works as expected :)

Sorry for the silly question.
- Andrea Gasparini -
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