Cd to nonexistent directory in /proc

[Jonathan Ryshpan]

On Fri, 2011-06-17 at 19:46 -0430, Patrick O'Callaghan wrote:
> On Fri, 2011-06-17 at 15:03 -0700, Jonathan Ryshpan wrote:
> > Investigating a hanging instance of googleearth (wich process number
> > 3110), I noticed that it's possible to 
> > 	cd /proc/3110
> > while on the other hand
> > 	ls /proc
> > does not show 3110 as being in the proc directory.
> > 
> > Any ideas what's going on?

> I can't imagine how that could happen, unless the directory entry
> disappeared between you doing the cd and the ls, perhaps because the
> process terminated. OTOH is you can reproduce this reliably, it could
> merit a Bugzilla report.

There's been a suggestion of a race condition.  Possibly, but if so it
was a very slow race.  The condition persisted over (I'd say) at least
10 minutes, during which time I did a number of "cd"s and "ls"s,
repeatedly getting the results reported above.  Unfortunately by now,
it's no longer possible to "cd /proc/3110" on the system.

If the condition ever repeats, I'll report further.  I was prompted to
look by the existence of
	/home/jonrysh/.googleearth/instance-running-lock
	(which is supposed to be a symbolic link to /proc/<googleearth-process>)
at a time when googleearth was not running.  Others may want to
investigate when this happens, which it does for me every month or so.

jon