[CRIU] [PATCH] proc_parse: fix vma file open mode recognition

[Andrew Vagin]

On Sun, Jul 10, 2016 at 08:33:34AM -0700, Andrew Vagin wrote:
> On Thu, Jul 07, 2016 at 11:43:59AM +0200, Stanislav Kinsburskiy wrote:
> > 
> > 
> > 07.07.2016 03:10, Andrew Vagin пишет:
> > > On Thu, Jun 30, 2016 at 07:24:45PM +0300, Stanislav Kinsburskiy wrote:
> > > > The correct place to get fd open flags for file mappings is
> > > > /proc/<pid>/map_files.
> > > > An attempt tp speculate on "shared" and "maywrite" bits doesn't garantee,
> > > > that file will be opened with correct permissions on restore.
> > > > Here is an example:
> > > > 
> > > > Process mapping (read/write):
> > > > 
> > > > # cat /proc/481943/maps | grep 7f7108077000-7f7108078000
> > > > 7f7108077000-7f7108078000 rw-p 00001000 00:35 7 <snip>
> > > > 
> > > > 1) Before suspend:
> > > > 
> > > > # ls -l /proc/481427/map_files/7f7108077000-7f7108078000
> > > > lrw------- <snip> /proc/481427/map_files/7f7108077000-7f7108078000 -> <snip>
> > > > 
> > > > 2) After restore:
> > > > 
> > > > # ls -l /proc/481943/map_files/7f7108077000-7f7108078000
> > > > lr-------- <snip> /proc/481943/map_files/7f7108077000-7f7108078000 -> <snip>
> > > > 
> > > > Write bit is lost.
> > > Could you add this check into zdtm.py?
> > > 
> > 
> > I'm sorry, but I have no idea where and how to do this.
> >
> 
> I'm sorry, but we accept patches only with tests;).
> 
> You need to add this check into get_visible_state() and
> check_visible_state().

I think it should be something like this:

diff --git a/test/zdtm.py b/test/zdtm.py
index 7072b62..23559fd 100755
--- a/test/zdtm.py
+++ b/test/zdtm.py
@@ -899,6 +899,12 @@ def get_visible_state(test):
                last = 0
                for mp in open("/proc/%s/root/proc/%s/maps" % (test.getpid(), pid)):
                        m = map(lambda x: int('0x' + x, 0), mp.split()[0].split('-'))
+
+                        f = "/proc/%s/root/proc/%s/map_files/%s" % (test.getpid(), pid, mp.split()[0])
+                        if os.access(f, os.F_OK):
+                                st = os.stat(f)
+                                m.append(st.st_mode)
+
                        if cmaps[last][1] == m[0]:
                                cmaps[last][1] = m[1]
                        else:

but zdtm.py doesn't detect any errors with this patch,
so you need to fix it to detect your issue.