[CRIU] CRIU saving/restoring fd for the device file

[Zmudzinski, Krystof C]

If the app runs uninterrupted by criu suspend/restore, each sys call to the driver works just fine: open returns valid fd and icotls return 0.  Also, errno is always 0.  After criu restore, open and ioctls still work and return valid fd and 0 respectively but errno is set to EINTR.  

Krystof

-----Original Message-----
From: Pavel Emelyanov [mailto:xemul at parallels.com] 
Sent: Thursday, October 2, 2014 8:17 AM
To: Zmudzinski, Krystof C; CRIU
Subject: Re: [CRIU] CRIU saving/restoring fd for the device file

On 10/02/2014 07:08 PM, Zmudzinski, Krystof C wrote:
> I have finally figured out that I can indeed talk to the driver just 
> fine.  The problem is that my code checks for errno even when ioctls 
> don't return -1.  For some reason, after resume, errno is set to 
> EINTR.  Is it possible that criu causes this by sending a signal to the my app during suspend?

I doubt this. errno is just a variable in memory, criu doesn't touch the app's memory.

> Shouldn't errno be cleared by criu on resume?

AFAIK no, app's memory should be left intact on restore.

Can you describe problem in more details, please?

Thanks,
Pavel