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

[Stanislav Kinsburskiy]

10.07.2016 20:47, Andrew Vagin пишет:
> On Sun, Jul 10, 2016 at 10:10:33AM -0700, Andrew Vagin wrote:
>> 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:
>                                  cmaps.append(m)
>                                  last += 1
> -               maps[pid] = set(map(lambda x: '%x-%x' % (x[0], x[1]), cmaps))
> +               maps[pid] = set(map(lambda x: '%x-%x %s' % (x[0], x[1], x[2:]), cmaps))
>
> But even with this fix it doesn't catch your problem and I can't reproduce it by hand.

Please, try static/unlink_mmap00 test.

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