Re: exit_mmap

From: Stephane (stephane.tessier@netinsight.se)
Date: Thu Mar 27 2003 - 10:23:32 EST


Actually I was talking about 2.4.19 but I saw that this was solved in
2.5,
sorry for the disturbance

Stephane wrote:
>
> I have a question about mmap and the close operation of a
> vm_area_struct.
> Is there a reason why in exit_mmap, when a process dies unexpectedly,
> the vm_ops->close is called before zap_page_range is called?
>
> The problem is that if you have allocated one or several kernel pages
> for a vm_area_struct, you can not free them in the vm_ops->close
> operation since the count field of the pages is not 0 because they are
> still mapped. The count will be cleared when zap_page_range is called.
>
> This means that exit_mmap calls vm_ops->close and zap_page_range in the
> reverse order of a normal execution of the process, that is when the
> process unmap the area before dying.
>
> It would be more deterministic and simple if vm_ops->close was always
> called when all the pages of the area was unmapped.
>
> PS: please can you CC'ed the answer to stephane.tessier@netinsight.se
> --
> Stephane Tessier
> Net Insight AB stephane.tessier@netinsight.se
> Västberga Allé 9 http://www.netinsight.se
> SE-126 30 Hägersten phone:+46-8-685 04 60
> Sweden fax: +46-8-685 04 20

-- 
Stephane Tessier
Net Insight AB          stephane.tessier@netinsight.se
Västberga Allé 9        http://www.netinsight.se
SE-126 30 Hägersten     phone:+46-8-685 04 60
Sweden                  fax:  +46-8-685 04 20
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