Re: Seeing lock order reversal

On 18/03/2008, Attilio Rao <attilio_at_freebsd.org> wrote:
> 2008/3/18, pluknet <pluknet_at_gmail.com>:
>
> > On 18/03/2008, Alex Goncharov <alex-goncharov_at_comcast.net> wrote:
>  >  > [ Sorry if this is old news or not useful ]
>  >  >
>  >  >  I am trying to source-upgrade one of my 7.0 systems to 8.0-CURRENT.
>  >  >
>  >  >  In the following, when I say "build", it means "csup and build right
>  >  >  away".
>  >  >
>  >  >  The very first 8.0 build (this morning) gave me the kernel that didn't
>  >  >  boot.  Built it again, finishing about 15 minutes ago.  This one
>  >  >  booted all right but I see this in `/var/log/messages':
>  >  >
>  >
>  > [there was stripped LORs]
>  >
>  >  It's due to recent WITNESS lockmgr support that unhides existing LORs.
>  >
>  >  Thought taking that into account I could obtain a new one yesterday. I
>  >  didn't see this before.
>  >
>  >  Mar 17 03:17:14 pl sudo:  pluknet : TTY=ttyv1 ; PWD=/usr/home/pluknet
>  >  ; USER=root ; COMMAND=/usr/libexec/getty 3wire.9600 ttyd0
>  >  Mar 17 03:17:14 pl kernel: lock order reversal:
>  >  Mar 17 03:17:14 pl kernel: 1st 0xc07e9274 proctree (proctree) _at_
>  >  /usr/src/sys/kern/kern_exit.c:291
>  >  Mar 17 03:17:14 pl kernel: 2nd 0xc2fc49e8 devfs (devfs) _at_
>  >  /usr/src/sys/kern/vfs_subr.c:2158
>
>
> This one seems interesting.
>  Next time you experience it can you please drop in DDB and print-out
>  the correct order revealed by WITNESS?
>
>  Thanks,
>  Attilio
>

btw, I also see this message in dmesg after LOR:
sio0: 170 more interrupt-level buffer overflows (total 170)

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pluknet