[CRIU] [PATCH] vma: don't skip vmas during searching a parent vma

[Andrew Vagin]

On Tue, May 13, 2014 at 05:48:07PM +0400, Pavel Emelyanov wrote:
> On 05/13/2014 05:18 PM, Andrew Vagin wrote:
> > On Tue, May 13, 2014 at 05:09:14PM +0400, Pavel Emelyanov wrote:
> >> On 05/13/2014 04:25 PM, Andrey Vagin wrote:
> >>> We stop searching if vma->start is bigger than a required one.
> >>> The coursor is set on the last examined vma. When we are searching a
> >>> parent vma for the next vma, we start examine vma-s starting from
> >>> coursor->next, so we don't examine the vma, which is pointed by cursor.
> >>>
> >>> This patch replaces list_for_each_entry_continue on list_for_each_entry_from.
> >>>
> >>> Reported-by: Filipe Brandenburger <filbranden at google.com>
> >>> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> >>
> >> Andrey, the recent 3 patches are great, but can you explain why keeping track
> >> of mm-dumpable bit breaks cow and we start requiring these fixes?
> > 
> > The test reports errors like this:
> > 17:14:08.431: 21816: ERR: cow01.c:78: Unable to open file /proc/21817/pagemap (errno = 13 (Permission denied))
> > 
> > These errors are ignored. cow01 worked fine when it was committed. Then
> > we decided to execute tests from a non-root user and the test starts
> > reports these error and stop to do something useful.
> 
> OK, but as you say -- test worked fine when it was committed. This means we
> broke COW at some point after moving tests into non superuser?

Yes, we did.
> 
> > commit 495c8007bcf24cbec542bc715901ca10e9c0d3fa
> > Author: Andrew Vagin <avagin at openvz.org>
> > Date:   Wed Apr 24 10:46:22 2013 +0400
> > 
> >     zdtm: execite test cases from a test user
> > 
> > I'm going to fix test too.
> > 
> >>
> >> Thanks,
> >> Pavel
> >>
> > .
> > 
> 
>