Ingo Molnar wrote:

>* Dimitri Sivanich <sivanich@sgi.com> wrote:
>
>
>>The isolcpus option is broken in 2.6.10-rc2-bk2.  The domains are no longer
>>being properly initialized (which results in a panic at bootup).
>>
>>The following patch fixes this.
>>
>>Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
>>
>
>Acked-by: Ingo Molnar <mingo@elte.hu>
>
>only a minor nit:
>
>
>>+	/* Initialize isolated CPU (physical) domains and groups */
>>+	for_each_cpu_mask(i, cpu_isolated_map) {
>>+		struct sched_domain *sd = NULL;
>>
>
>there's no need to initialize 'sd' to NULL here.
>
>
>>+		int group;
>>+
>>+		sd = &per_cpu(phys_domains, i);
>>+		group = cpu_to_phys_group(i);
>>
>
>>+	for_each_cpu_mask(i, cpu_isolated_map) {
>>+		struct sched_domain *sd = NULL;
>>
>
>ditto.
>
>
>>+		int group;
>>+
>>+		sd = &per_cpu(phys_domains, i);
>>+		group = cpu_to_phys_group(i);
>>+		*sd = SD_CPU_INIT;
>>
>
>	Ingo
>
>
>

Actually, this is wrong. And I was wrong to say that the fix was
to initialize the dummy domain (because its ->flags are 0, there
is no need for it to have anything else set up).

The isolated domains don't need to be set up because they correctly
point to the dummy domain, which is already set up properly (zeroed).
The oops is just a problem with sched_domain_debug.

Andrew and/or Linus, please make sure Dimitri's patch gets reverted
and the attached one applied before 2.6.10.