[collectd] exec plugin stuck on mutex

[Florian Forster]

Hi Ryan,

sorry for the late reply, I lost track :/

On Tue, Mar 09, 2010 at 12:24:20PM -0800, Ryan Tomayko wrote:
> > such a weird child. Maybe the signal mask or UID/GID can tell me
> > which step would be the next and might be the failing one.
> 
> You got it:
> 
> # cat /proc/25335/status
> […]
> SigBlk: 0000000000000000

Looks like the block mask was already reset. That's the last thing
that's done before calling "exec_child".

> […]
> Uid:    0       0       0       0
> Gid:    0       0       0       0
> Groups: 0

Okay, so neither the supplementary groups, the GID nor the UID have been
set. This makes it likely that one of the following calls is causing
the observed behavior:

  * getpwnam_r
  * getgrnam_r (only if a group was configured)
  * setgroups

How do you do authentication on that machine? Are you using LDAP for
example?

I think the best way to know for sure where the process is hanging is by
using a version with debugging symbols available (the Debian package
provides those, for example, but you can also compile with
--enable-debug) and attach a debugger to the process once it's hanging.

Regards,
—octo
-- 
Florian octo Forster
Hacker in training
GnuPG: 0x91523C3D
http://verplant.org/
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