UFS/VFS lock order reversal on stock 8.0-200812-AMD64

[Paul Tice]

-----Original Message-----
From: Gavin Atkinson [mailto:gavin at FreeBSD.org]
Sent: Fri 1/23/2009 6:19 AM
To: Paul Tice
Cc: freebsd-current at FreeBSD.org
Subject: Re: UFS/VFS lock order reversal on stock 8.0-200812-AMD64
 
On Fri, 2009-01-23 at 12:07 +0000, Gavin Atkinson wrote:
> On Thu, 2009-01-22 at 21:33 -0600, Paul Tice wrote:
> > I'm new, so please advise me (gently?) about list protocol and such if needed.
> > 
> > Using stock 8.0-CURRENT-200812-amd64, I am getting the messages below.
> 
> 8.0-CURRENT is essentially the bleeding-edge of FreeBSD, and is where
> development happens that has not necessarily proven itself as being
> stable.  As it is the development branch, it also has a lot of extra
> debugging enabled, which is what you are seeing with the "lock order
> reversals".
> 
> If you are not running 8-CURRENT for a specific reason (e.g. because you
> are doing FreeBSD OS development work, or you are prepared to help debug
> issues as you encounter them, or similar), you probably shouldn't be
> running CURRENT.  Stick with 7.1.

>I should have also included (in answer to your actual question):
>Neither the lock order reversals or the corrupted messages on shutdown
>are anything you need worry about.

>Gavin


I wouldn't have asked if I wasn't willing to help debug (as possible, and with very little coding knowledge.)

I pulled out the 'extra debugging', made world and kernel, and rebooted.
Notice the 5th line of da7's drive ID being interleaved with 'SMP: AP CPU #1 Launched!'

I'm fairly sure this is not a good thing, if for no other reason that 'apparent garbage' in dmesg is not useful.

da6 at mpt0 bus 0 target 6 lun 0
da6: <ATA ST3750640AS K> Fixed Direct Access SCSI-5 device 
da6: 300.000MB/s transfers
da6: Command Queueing Enabled
da6: 715404MB (1465149168 512 byte sectors: 255H 63S/T 91201C)
da7 at mpt0 bus 0 target 7 lun 0
da7: <ATA ST3750640AS K> Fixed Direct Access SCSI-5 device 
da7: 300.000MB/s transfers
da7: Command Queueing Enabled
da7: 715404MB (1465149168 512 bytSeM Ps:e cAtPo rCsP:U  2#515 HL a6u3nSc/hTe d9!12
01C)
SMP: AP CPU #3 Launched!
SMP: AP CPU #2 Launched!
SMP: AP CPU #7 Launched!
SMP: AP CPU #4 Launched!
SMP: AP CPU #6 Launched!
SMP: AP CPU #5 Launched!
Trying to mount root from ufs:/dev/ad20s1a


Thank You
Paul