Strange ``tail -f'' behaviour - kqueue-related?

[Paul Goyette <paul%whooppee.com@localhost>]

I've been seeing some very odd behaviour lately, with ``tail -f''.

I've got a bunch of packages being built (in a chroot sandbox), and
occassionally I do a ``tail -f'' on the current package's log file
just to make sure it is still making progress.  So the file is open
by both the package-building shell and the tail process.

Occassionally the tail process fails to notice any further changes
to the file's size, and just sits there.  Indeed, it is now more
than 30 minutes since a particular build completed (and the shell
has long ago closed the log file), but the tail output is still
stuck somewhere in the middle of the file.  (I've seen this a few
times now, and while it happens again and again, it does not seem
predictable on when it might happen.)

I'm wondering if some of the recent changes to kqueue might be
responsible.  I don't ever remember seeing this prior to my recent
update from 9.99.92 to .93

I can keep the "hung" tail process around for a while in case of
any diagnostic requests.


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