race between geom and root mount

Hi,

The last day I have been trying to setup a geom mirror to boot from. I
have tried various ways of configuring it, geom mirror on the raw disk
and also geom mirror inside a slice, also without any slices etc. But
everytime I could get it to load the kernel and boot up to the point
where it should mount the root partition and then it would fail and
give the prompt where you can type the name of the root partition you
want to mount. Even by typing the partition name at the prompt could
not get it to work. Then today I noticed that after I got the prompt
for the root partition a few more geom messages were printed. Then I
disabled smp by setting kern.smp.disabled="1" and it booted fine.

This is with 5.3-BETA4 and BETA5 and a 3GHz single processor machine
with HTT enabled. The last part of dmesg after a successfull boot
looks like this:

Timecounter "TSC" frequency 2992509495 Hz quality 800
Timecounters tick every 10.000 msec
acpi_cpu: throttling enabled, 8 steps (100% to 12.5%), currently 100.0%
em0: Link is up 100 Mbps Full Duplex
ad4: 76319MB <ST380013AS/3.18> [155061/16/63] at ata2-master SATA150
GEOM_LABEL: Label for provider ad4 is label/disk0.
ad6: 76319MB <ST380013AS/3.18> [155061/16/63] at ata3-master SATA150
GEOM_MIRROR: Device gm0 created (id=792435012).
GEOM_MIRROR: Device gm0: provider label/disk0 detected.
GEOM_LABEL: Label for provider ad6 is label/disk1.
GEOM_MIRROR: Device gm0: provider label/disk1 detected.
GEOM_MIRROR: Device gm0: provider label/disk1 activated.
GEOM_MIRROR: Device gm0: provider label/disk0 activated.
GEOM_MIRROR: Device gm0: provider mirror/gm0 launched.
Mounting root from ufs:/dev/mirror/gm0a

John
-- 
John Hay -- John.Hay_at_icomtek.csir.co.za / jhay_at_FreeBSD.org