Thanks you Tom and George for the tips on using kgdb with
2.6.13-rc4-mm1.
I almost have it working but kgdb seems to have a few issues. I can get
it running from the dev machine using the kgdb and console=kgdb boot
options on the test kernel. The kernel waits as it should and when I
attach with "target remote /dev/ttyS0" and I can continue the boot but
eventually it gets to a point in the boot where it frees unused kernel
memory successfully and then a warning, "unable to open an initial
console", followed by, "Kernel panic - not syncing: Attempted to kill
init!"
Removing the console=kgdb boot option and the machine boots all the way
to run level 5. I tried to break into kgdb at this point using the $echo -e "\003" > /dev/ttyS0
from the dev machine but the test kernel panics at gdb_interrupt+75 when
it receives anything on the serial port. Hmmm...
I'm wondering if I'm maybe just the first to try this on EM64T (kernel
builds in the arch/x86_64 tree).
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