devfs

[Robert Watson]

On Tue, 3 Jan 2006, TSaplin Mikhail wrote:

> Hi all i have a problem with devfs device hiding.
> My system is FreeBSD 6.0 (i386 and amd64, compiled from last sunday source
> (RELENG_6))
>
> After mounting defs:
> #mount -t devfs devfs /tmp/proba
>
> first devfs command:
> # devfs -m /tmp/proba rule add type disk hide
> devfs rule: ioctl DEVFSIO_RADD: Input/output error
>
> the second command hangs:
> # devfs -m /tmp/proba rule add type disk hide
>
> command doesnt responds on HUP and TERM signals

A week or two ago I fixed a bug in devfs where an error condition results in a 
lock leak, followed by hanging processes and a deadlock.  I merged the change 
to RELENG_6 this morning having returned from India yesterday night.  If a 
fair number of people are running into this, we may want to merge it to 
RELENG_6_0 and do an errata announcement for it.  The change you want is this 
one:

   revision 1.21
   date: 2006/01/03 09:49:10;  author: rwatson;  state: Exp;  lines: +4 -2
   When returning EIO from DEVFSIO_RADD ioctl, drop the exclusive rule
   lock.  Otherwise the system comes to a rather sudden and grinding
   halt.

   MFC after:      1 week

I ran into it while on travel, as I was trying to get devfs to make /dev/bpf* 
readable by the operator group, and typed the command wrong.  The RELENG_6 
revision is devfs_rule.c:1.14.2.3.

Robert N M Watson