[PATCH] sched: tasks cannot run on cpus onlined after boot

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@pobox.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/kernel/sched.c b/kernel/sched.c
index a7aeb71140a6cf5b1231ce770382f94dd0a4ee75..0512417de3054c6d2f90de630040bf9f00fb88e2 100644 (file)
--- a/kernel/sched.c
+++ b/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();