SMP BUG

From: Hubertus Franke
Date: Mon Feb 13 2006 - 19:17:16 EST


Folks the change introduced in 2.6.16-rc2 over 2.6.15
wrt to the SMP initialization are wrong.
Please apply to unroll the change..

Here is the logic ...
sched_init is called from start_kernel before the
architecture specific function cpu_check_smp() is called
which is done as part of rest_init().

On s390 this actually sets the cpu_possible_map, which
is now used in sched_init through the for_each_cpu without
properly being initialized.
As a result bringing 2nd and subsequent cpu online
breaks.

This should be a quick fix, until this chicken and egg
problem is solved otherwise.

-- Hubertus

--- kernel/sched.c.orig 2006-02-13 19:08:28.000000000 -0500
+++ kernel/sched.c 2006-02-13 19:09:08.000000000 -0500
@@ -6111,7 +6111,7 @@ void __init sched_init(void)
runqueue_t *rq;
int i, j, k;

- for_each_cpu(i) {
+ for (i = 0; i < NR_CPUS; i++ ) {
prio_array_t *array;

rq = cpu_rq(i);

-
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