[013/151] sched: Fix affinity logic in select_task_rq_fair()

[Greg KH]

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

------------------

From: Mike Galbraith <efault@xxxxxx>

commit fd210738f6601d0fb462df9a2fe5a41896ff6a8f upstream.

Ingo Molnar reported:

[   26.804000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10
[   26.808000] caller is vmstat_update+0x26/0x70
[   26.812000] Pid: 10, comm: events/1 Not tainted 2.6.32-rc5 #6887
[   26.816000] Call Trace:
[   26.820000]  [<c1924a24>] ? printk+0x28/0x3c
[   26.824000]  [<c13258a0>] debug_smp_processor_id+0xf0/0x110
[   26.824000] mount used greatest stack depth: 1464 bytes left
[   26.828000]  [<c111d086>] vmstat_update+0x26/0x70
[   26.832000]  [<c1086418>] worker_thread+0x188/0x310
[   26.836000]  [<c10863b7>] ? worker_thread+0x127/0x310
[   26.840000]  [<c108d310>] ? autoremove_wake_function+0x0/0x60
[   26.844000]  [<c1086290>] ? worker_thread+0x0/0x310
[   26.848000]  [<c108cf0c>] kthread+0x7c/0x90
[   26.852000]  [<c108ce90>] ? kthread+0x0/0x90
[   26.856000]  [<c100c0a7>] kernel_thread_helper+0x7/0x10
[   26.860000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10
[   26.864000] caller is vmstat_update+0x3c/0x70

Because this commit:

  a1f84a3: sched: Check for an idle shared cache in select_task_rq_fair()

broke ->cpus_allowed.

Signed-off-by: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: arjan@xxxxxxxxxxxxx
LKML-Reference: <1257415066.12867.1.camel@xxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 kernel/sched_fair.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1415,6 +1415,8 @@ static int select_task_rq_fair(struct ta
 
 				if (candidate == -1 || candidate == cpu) {
 					for_each_cpu(i, sched_domain_span(tmp)) {
+						if (!cpumask_test_cpu(i, &p->cpus_allowed))
+							continue;
 						if (!cpu_rq(i)->cfs.nr_running) {
 							candidate = i;
 							break;


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