[CRIU] [PATCH 2/3] mem: if no parent image persists, can't rely on it

[Pavel Tikhomirov]

Eventually, I can imagine only one possibility of why initial problem can
happen. If child don't write to memory at all, and then dump happens, and
criu will see dirty bits in child as they were in parent, becouse there
were no PF's.

Best Regards, Tikhomirov Pavel.


2014-04-15 23:27 GMT+04:00 Cyrill Gorcunov <gorcunov at gmail.com>:

> On Tue, Apr 15, 2014 at 11:15:19PM +0400, Cyrill Gorcunov wrote:
> > On Tue, Apr 15, 2014 at 11:07:28PM +0400, Pavel Tikhomirov wrote:
> > >    Please read this comment.
> > >    Best Regards, Tikhomirov Pavel.
> > >
> > >    2014-04-15 17:43 GMT+04:00 Pavel Tikhomirov <snorcht at gmail.com>:
> > >
> > >      Ok, but what if parent writes to memory first and gets COW'ed,
> > >      and child gets writable memory when access it.
> > >      It can result in no PF.
> > >      Just an Idea, need to understand COW mechanism more precisely.
> >
> > OK, as far as I remember, once the process is forked, its pte/pmd
> structures
> > become allocated but not present, once child attempt to read something,
> the
>
> Sorry, for COW there is copy_one_pte which would WP both parent and child.
>
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