Subject: deadlocks, many processes in sleepq_block
To: None <>
From: Anthony Mallet <>
List: tech-kern
Date: 09/20/2007 18:01:27
Hi all,

Since a few weeks (let's say since ~ august 20th), my -very-current with
option MULTIPROCESSOR freezes _very_ often.
I can trigger this problem in a few seconds under X11 with 1000baseT
network and nfs activity, but it takes some minutes under X11 with
100baseT network and nfs activity. The most strange is that I triggered
it once without option MULTIPROCESSOR (i.e. mono processor).
But it never happened in console mode.

The symptoms are the following:
- no network, no filesystem acces.
- kernel is still alive, processes that do no IO at all continue to work
  (e.g. I can switch my virtual desktops under X).
- I can kill X (ctrl-alt-bkspace) and enter ddb.

A ps in ddb always shows the same three active processes: 
firefox-bin & gkrellm & nfsd.
Every single process seems to be hung in sleepq_block() and the three
above were doing some nfs-related operations before ending up in

Is there something I should try/investigate in order to find the source
of the problem? Is it an already known problem?
Any help appreciated :)

-- Anthony