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#27 DMTCP
Hi Team,
I'm trying to use DMTCP in Ubuntu 12.04 LTS.
I have installed DMTCP 1.2.1.1 version. When I try to checkpoint a process, error comes as Segmentation fault (core dumped). I dont know how to debug it.
I have also tried DMTCP 2.0. In this checkpointing is working and files are created. But while restarting it shows "Running mtcp_restart as root is dangerous.Aborting If you still want to do this (at your own risk), then modify mtcp/mtcp_restart.c:96 and re-compile.
Segmentation fault (core dumped)".
I have attached screenshots for your reference
Thanks and Regards,
Poovannan.
Hi Poovannan,
Are you running DMTCP under root account? Generally it is not advisable as
running DMTCP under root can cause some security issues? Could you confirm
that?
Also, 1.2.1-1 is a really old version. I would recommend you to do further
testing on 2.0 only.
Kapil
On Tue, Oct 29, 2013 at 2:20 AM, poovannan poovannan89@users.sf.net wrote:
Related
Bugs: #27
Hi Kapil,
Thank you for your quick response. Yes, I ran dmtcp under root account.
I have tried using DMTCP 2.0 also. But restarting a checkpointed process in dmtcp 2.0 throws error as "Process uid (1000) doesn't match uid (0) of
checkpoint image (ckpt_fo_645e4cfc-40000-526f6bcc.dmtcp).
This is dangerous. Aborting for security reasons.
If you still want to do this (at your own risk),
then modify dmtcp/src/dmtcp_restart.cpp:383 and re-compile."
This error is thrown even while running without under root account. I have enclosed the screenshot for your reference.
Also, I want to know, to restart the same process in another machine, we need to transfer the checkpoint file and run restart script right ?
Hi Kapil,
Actually, I ran dmtcp launch under root account and restart under normal account. Since, the error shows Process uid doesnot match it may be the reason.
But,if I try to run dmtcp launch under normal account , it shows error as "Missing execute or write access to checkpoint dir".
I have enclosed the screen shot of running dmtcp_launch under normal account.
Hi Poovannan.
Kapil and I are both part of the team. So, I'll add the next question. :-)
First, one comment: if you don't need root privilege for this
application, it would be best not to use it. We will be adding direct
support for changing uid's between checkpoint and restart (and we can
offer you a quick hack right now for that), but it will be best to run
only as a normal user.
Second, you write:
For now, since I don't know the details of your app, I'll make crude guess.
If I'm right, it may save a round of e-mail. I'll guess that you checkpointed
when there were some open files in one directory. Then perhaps you
copied the checkpoint image to another directory or another computer.
And so, the restarted image is having trouble finding the location of the
files that had been opened prior to checkpoint. Is this the case for you?
(If you like, we'd also be happy to arrange a phone call for the details.)
Best,
- Gene
On Tue, Oct 29, 2013 at 08:33:46AM +0000, poovannan wrote:
Related
Bugs: #27
Hi Gene/Kapil,
Thank your so much for your reply and valuable time. I have figured out my problem and dmtcp 2.0 is working completely fine.
I think the problem is because I installed dmtcp from root user mode and tried to execute checkpoint/restart in normal user mode. While using, "make check" command during installation also, restart of test programs failed.
I have reinstalled dmtcp from normal user and is working great.
As of now,I have just tried using a simple C program as application.
I really love to be in contact with you and your team.It feels great to have team looking into issues of users with much attention.As of now, I have started my work on checkpointing in Android and computation offloading to cloud nodes from mobiles.
Thanks and Regards,
Poovannan.E
(91+)9789195923.