Re: Boot hang in 2.5.3-pre2

[Ingo Molnar]

On Mon, 21 Jan 2002, Dave Jones wrote:

>  >   Hi, Linus. FYI: 2.5.3-pre2 hangs during boot. The last couple of
>  > messages I get are:
>  > Based upon Swansea University Computer Society NET3.039
>  > apm: BIOS version 1.2 Flags 0x03 (Driver version 1.15)
>  > apm: disabled - APM is not SMP safe (power off active).
>
>  Ingo's scheduler patches solved this one for me (and others).

the bug is the following: the 2.5.3-pre2 kernel in essence includes the
-I3 patch. The -I3 scheduler doesnt have the task migration fixes yet, but
has the improved load-balancer. And exactly this improved load-balancer
makes task-migration much more likely to happen during bootup =>
triggering it for ksoftirqd migration, resulting in a hang.

older versions had the migration bug as well, but the first iteration of
the load-balancer was much less accurate at balancing runqueues, so it
didnt trigger the bug.

	Ingo