[patch 14/59] sched: tasks cannot run on cpus onlined after boot

[Chris Wright]

-stable review patch.  If anyone has any objections, please let us know.
------------------

From: Nathan Lynch <ntl@xxxxxxxxx>

Commit 5c1e176781f43bc902a51e5832f789756bff911b ("sched: force /sbin/init
off isolated cpus") sets init's cpus_allowed to a subset of cpu_online_map
at boot time, which means that tasks won't be scheduled on cpus that are
added to the system later.

Make init's cpus_allowed a subset of cpu_possible_map instead.  This should
still preserve the behavior that Nick's change intended.

Thanks to Giuliano Pochini for reporting this and testing the fix:

http://ozlabs.org/pipermail/linuxppc-dev/2006-December/029397.html

Signed-off-by: Nathan Lynch <ntl@xxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 kernel/sched.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-2.6.19.2.orig/kernel/sched.c
+++ linux-2.6.19.2/kernel/sched.c
@@ -6765,7 +6765,7 @@ void __init sched_init_smp(void)
 
 	lock_cpu_hotplug();
 	arch_init_sched_domains(&cpu_online_map);
-	cpus_andnot(non_isolated_cpus, cpu_online_map, cpu_isolated_map);
+	cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
 	if (cpus_empty(non_isolated_cpus))
 		cpu_set(smp_processor_id(), non_isolated_cpus);
 	unlock_cpu_hotplug();

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