[CRIU] [PATCH 2/2] cr-check: add compat_restore check

[Dmitry Safonov]

On 01/10/2017 04:06 PM, Dmitry Safonov wrote:
> On 01/10/2017 03:34 PM, Pavel Emelyanov wrote:
>> On 01/09/2017 07:59 PM, Dmitry Safonov wrote:
>>> Initialy, I thought to name it "compat_restore", but after I've dropped
>>> the second 32-bit parasite (which surely made compat code lesser and
>>> easier), our parasite works in 64-bit in 32-bit task and ptrace()
>>> for setting registers in this long-jumped situation will work correctly
>>> only after v4.9 kernel. Maybe it can be work-arounded if needed,
>>> but yet no compatible dump for pre-v4.9 kernels.
>>>
>>> Requested-by: Andrei Vagin <avagin at virtuozzo.com>
>>> Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
>>> ---
>>>  criu/cr-check.c | 10 ++++++++++
>>>  1 file changed, 10 insertions(+)
>>>
>>> diff --git a/criu/cr-check.c b/criu/cr-check.c
>>> index 60279e135dfa..94c5074557ce 100644
>>> --- a/criu/cr-check.c
>>> +++ b/criu/cr-check.c
>>> @@ -48,6 +48,7 @@
>>>  #include "libnetlink.h"
>>>  #include "net.h"
>>>  #include "linux/userfaultfd.h"
>>> +#include "restorer.h"
>>>
>>>  static char *feature_name(int (*func)());
>>>
>>> @@ -1134,6 +1135,14 @@ static int check_loginuid(void)
>>>      return 0;
>>>  }
>>>
>>> +static int check_compat_cr(void)
>>
>> Call for this should also be added to cr_check()
>
> Hmm, and what about tun/userns/loginuid features?
> Should them be also in cr_check()?
> I don't completely get the policy why some are(not) there.

Tun is actually checked with other parameter.
Should userns and loginuid also be in cr_check()?

>
>>
>>> +{
>>> +    if (kdat_compat_sigreturn_test())
>>> +        return 0;
>>> +    pr_err("compat_cr is not supported. Requires kernel >= v4.9\n");
>>> +    return -1;
>>> +}
>>> +
>>>  struct feature_list {
>>>      char *name;
>>>      int (*func)();
>>> @@ -1154,6 +1163,7 @@ static struct feature_list feature_list[] = {
>>>      { "autofs", check_autofs },
>>>      { "tcp_half_closed", check_tcp_halt_closed },
>>>      { "lazy_pages", check_uffd },
>>> +    { "compat_cr", check_compat_cr },
>>>      { NULL, NULL },
>>>  };
>>>
>>>
>>
>
>


-- 
              Dmitry