[CRIU] remap_dead_pid test hang?

[Andrew Vagin]

On Thu, Mar 19, 2015 at 10:01:07PM +0300, Pavel Emelyanov wrote:
> On 03/19/2015 09:54 PM, Tycho Andersen wrote:
> > On Thu, Mar 19, 2015 at 07:36:41PM +0300, Pavel Emelyanov wrote:
> >> On 03/19/2015 05:54 PM, Tycho Andersen wrote:
> >>> Hi all,
> >>>
> >>> While testing the cgroup property restore patch, I noticed that the
> >>> remap_dead_pid test seems to hang both with my patch and the current
> >>> master. Has anyone else noticed this?
> >>
> >> No. We have Jenkins running full zdtm suite (and more) in 7x24 manner
> >> and though it fails sometimes, but we haven't met any issues with this
> >> particular test.
> >>
> >> Does the test hang by itself, or after restore?
> > 
> > How do I tell? It looks like it's just hung:
> > 
> > root     32749  0.0  0.1  11652  3292 pts/1    S    18:49   0:00 /bin/bash ./zdtm.sh --ct -r static/remap_dead_pid
> > root       314  0.0  0.0   4196   644 pts/1    S    18:49   0:00  \_ ./zdtm_ct ./zdtm.sh -r static/remap_dead_pid
> > root       370  0.0  0.1  11752  3476 ?        Ss   18:49   0:00      \_ /bin/bash ./zdtm.sh -r static/remap_dead_pid
> > root     15963  0.0  0.1  11752  2372 ?        S    18:49   0:00          \_ /bin/bash ./zdtm.sh -r static/remap_dead_pid
> > root     15964  0.0  0.1   8464  2332 ?        S    18:49   0:00              \_ make -C zdtm/live/static remap_dead_pid.pid
> > 18943    17937  0.0  0.0   4492   816 ?        S    18:49   0:00                  \_ ./remap_dead_pid --pidfile=remap_dead_pid.pid --outfile=remap_dead_pid.out
> > 18943    17940  0.0  0.0   4492   104 ?        Ss   18:49   0:00                      \_ ./remap_dead_pid --pidfile=remap_dead_pid.pid --outfile=remap_dead_pid.out
> > 18943    17941  0.0  0.0   4492  1136 ?        S    18:49   0:00                          \_ ./remap_dead_pid --pidfile=remap_dead_pid.pid --outfile=remap_dead_pid.out
> 
> Hm... :) There should be a directory where criu is supposed to put it's output
> (logs and images), the test/dump/ one if I'm not mistaken. Then you can check
> the remap_dead_pid's directory to container dump.log or restore.log to find
> out whether any of those actions took place.
> 
> 
> > This only seems to happen when I run it via `sudo make test`. If I run it via
> > `sudo ./zdtm.sh -r static/remap_dead_pid`, it completes successfully.
> 
> That's interesting :) Andrey, do you have any ideas why this can happen?

No, I don't. I tried to reproduce on my ubuntu VM, but it works.

Tycho, could you apply this patch to be sure that kill doesn't return
an error.

@@ -45,7 +45,10 @@ int main(int argc, char **argv)
                fd = open(path, O_RDONLY);
 
                /* no matter what, we should kill the child */
-               kill(pid, SIGINT);
+               if (kill(pid, SIGINT)) {
+                       err("kill");
+                       return -1;
+               }
                result = waitpid(pid, NULL, 0);
                if (result < 0) {
                        fail("failed waitpid()");

> 
> Thanks,
> Pavel
> 
>