[CRIU] [PATCH 5/8] parasite: restore registers after each parasite command

[Pavel Emelyanov]

On 07/16/2013 01:44 PM, Andrew Vagin wrote:
> On Tue, Jul 16, 2013 at 01:45:56PM +0400, Pavel Emelyanov wrote:
>> On 07/15/2013 11:19 PM, Andrew Vagin wrote:
>>> On Mon, Jul 15, 2013 at 09:03:42PM +0400, Pavel Emelyanov wrote:
>>>> On 07/11/2013 01:46 PM, Andrey Vagin wrote:
>>>>> Currenly we can restore blocking signals with help ptrace,
>>>>> so if registers are restored after command, a process state
>>>>> will not be corrupted if criu crashes.
>>>>
>>>> If criu crashes the sigreturn rescue code will restore the regs. No?
>>>
>>> Yes, but two commands are required, that a parasite is able to restore
>>> itself via sigreturn:
>>> * allocate parasite_ctl
>>> * parasite_init_daemon()
>>>
>>> crtools can crash between these two commands, so we need this and
>>> previos patch. This logic is used for dumping threads too.
>>
>> crtools can crash between set_sigmask(blockall) and set_sigmask(prev_blocked),
>> so why do we need this change? Only to reduce this risky window?
> 
> Yes

That's ... strange. I would understand if we had only single
window at which crtools crash means app crash. But we have
several sequential of them. Can we fix it?