Hang near end of kernel probes since r213267 (likely earlier)

[David Wolfskill]

On Fri, Oct 01, 2010 at 04:30:01PM -0700, David Wolfskill wrote:
> ...
> I found the disabling the "Module Bay" appears to avoid the hang --
> reliably.
> 
> That appears to be the minimally-invasive change necessary to avoid the
> hang.
> ....

Until I realized what was in the Modular Bay: the CD/CVD reader/burner.

So I tried a variation on the theme:  I left all the devices enabled,
but I physically removed the device from the bay before booting -- and
was unable to get it to fail.

And -- just now -- I disabled the channel (via atacontrol(8)), inserted
the drive, and enabled the channel:

g1-222# atacontrol list
ATA channel 0:
    Master:      no device present
    Slave:       no device present
ATA channel 1:
    Master:      no device present
    Slave:       no device present
ATA channel 2:
    Master:  ad4 <ST9250421ASG/DE16> SATA revision 2.x
    Slave:       no device present
ATA channel 3:
    Master:      no device present
    Slave:       no device present
ATA channel 4:
    Master:      no device present
    Slave:       no device present
ATA channel 5:
    Master:      no device present
    Slave:       no device present
g1-222# atacontrol detach ata3
g1-222# atacontrol list
ATA channel 0:
    Master:      no device present
    Slave:       no device present
ATA channel 1:
    Master:      no device present
    Slave:       no device present
ATA channel 2:
    Master:  ad4 <ST9250421ASG/DE16> SATA revision 2.x
    Slave:       no device present
ATA channel 3:
    Master:      no device present
    Slave:       no device present
ATA channel 4:
    Master:      no device present
    Slave:       no device present
ATA channel 5:
    Master:      no device present
    Slave:       no device present
g1-222# atacontrol attach ata3
Master: acd0 <TSSTcorp DVD+/-RW TS-U633A/D200> SATA revision 1.x
Slave:       no device present
g1-222# atacontrol list
ATA channel 0:
    Master:      no device present
    Slave:       no device present
ATA channel 1:
    Master:      no device present
    Slave:       no device present
ATA channel 2:
    Master:  ad4 <ST9250421ASG/DE16> SATA revision 2.x
    Slave:       no device present
ATA channel 3:
    Master: acd0 <TSSTcorp DVD+/-RW TS-U633A/D200> SATA revision 1.x
    Slave:       no device present
ATA channel 4:
    Master:      no device present
    Slave:       no device present
ATA channel 5:
    Master:      no device present
    Slave:       no device present
g1-222# 

This is running:

FreeBSD g1-222.catwhisker.org. 9.0-CURRENT FreeBSD 9.0-CURRENT #1 r213322: Fri Oct  1 10:18:30 PDT 2010     root at g1-222.catwhisker.org.:/usr/obj/usr/src/sys/CANARY  i386

Any ideas on what mught be causing CURRENT to hang -- sometimes
-- given that it appears to involve the Modular Bay (or the specific
device that is in the bay during the hang)?

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Depriving a girl or boy of an opportunity for education is evil.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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