[lttng-dev] lttng create freezes sometimes

[Sébastien Barthélémy]

Hello David,

thank you for your help.

2012/1/9 David Goulet <david.goulet at polymtl.ca>:
> Well, I can't recreate this problem on my side... Looking at the log you posted,
> you got a successful create and after a failure or... ?

I killed the session daemon between each of the attempts above. So that
``lttng create`` has to spawn the session daemon at each attempt.

> It seems that the command never reached the session daemon... and this is
> *really* weird and almost impossible.

I'm not sure which command and session daemon you're talking about.

``lttng create`` spawns the daemon, and sometimes it works, sometimes they seem
to deadlock.

In the strace, you'll see the SIGCHILD which should normally (if I got
it right) wake up
lttng

> Can you give me more details about your setup.
>
> Kernel version

2.6.29.6-rt24 with preempt_rt fully enabled

> glibc version

2.11.3

> urcu version

0.6.7

> lttng-tools version you are using or commit id.

2.0-pre16

These are the versions from the last bundle
(http://lttng.org/files/bundles/20111223/)

I also tried on another target with the same software stack except for
linux which is
2.6.33.9-rt31. I could not reproduce the problem on this system (it has more CPU
too).

> Of course, I'll encourage you to use the latest git head of lttng-tools and try
> it out.

Well, my version is almost head already.

> Thanks for the report!

You're welcome

-- Sébastien