[CRIU] Criu mod to restore files to state when checkpoint taken ...

[Christopher Covington]

On 01/03/2015 09:36 AM, Tycho Andersen wrote:
> On Fri, Jan 02, 2015 at 01:22:15PM -0500, Christopher Covington wrote:
>> Hi Pavel,
>>
>> On 12/31/2014 08:50 AM, Pavel Emelyanov wrote:
>>> On 12/31/2014 03:53 PM, "Mark O'Neill" wrote:
>>
>>>> 3. The required kernel functions (described on Criu website) must be
>>>> added as modules (-=m) and not hardwired into kernel (=y) in Linux
>>>> config file.
>>>
>>> This is strange. What problems have you seen with all-in kernel?
>>
>> At least for me, commit 2b5d06817f1bb2b28eec50b6705b1584435e580b introduced
>> the following, which is actually spurious:
>>
>> (00.098217) Error (util.c:576): exited, status=1
>> (00.164971) Error (util.c:576): exited, status=1
>> (00.216945) Error (util.c:576): exited, status=1
>> (00.296716) Error (util.c:576): exited, status=1
>> (00.368518) Error (util.c:576): exited, status=1
>>
>> I originally proposed [1] a somewhat complex change of probing
>> /proc/config.gz, but I think a quick and actually more general (as it doesn't
>> require /proc/config.gz which is itself a configuration option) fix is to pass
>> an fd to /dev/null into the cr_system() call.
> 
> Yes, the /dev/null trick seems a little nicer. Let me know if you want
> me to send a patch; I haven't had much time for criu recently, but I'm
> happy to fix the mess I created :)

Unfortunately, my instance of that change doesn't actually work. Only the
forked child uses the file descriptors passed as arguments to cr_system() in
util.c. The error handling logic of the parent uses pr_err, which is a macro
around print_on_level and uses the log fd.

Chris

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