From: Wanpeng Li <wanpeng...@hotmail.com>
WARNING: CPU: 0 PID: 3404 at arch/x86/kernel/smp.c:125
native_smp_send_reschedule+0x3f/0x50
CPU: 0 PID: 3404 Comm: qemu-system-x86 Not tainted 4.8.0+ #21
Call Trace:
__warn+0xd1/0xf0
warn_slowpath_null+0x1d/0x20
native_smp_send_reschedule+0x3f/0x50
trigger_load_balance+0x29c/0x4a0
? trigger_load_balance+0x72/0x4a0
scheduler_tick+0x9f/0xd0
? tick_sched_do_timer+0x50/0x50
update_process_times+0x47/0x60
tick_sched_handle.isra.24+0x25/0x60
tick_sched_timer+0x3d/0x70
__hrtimer_run_queues+0xf4/0x510
hrtimer_interrupt+0xb7/0x1d0
local_apic_timer_interrupt+0x35/0x60
smp_apic_timer_interrupt+0x3d/0x50
apic_timer_interrupt+0x96/0xa0
If there is a need to kick the idle load balancer, an ILB will be selected
to perform nohz idle load balance, however, if the selected ILB is in the
process of offline, smp_sched_reschedule() which generates a sched IPI will
splat as above.
CPU0 CPU1
find_new_ilb()
set_rq_offline()
smp_sched_reschedule() Oops
nohz_balance_exit_idle()
This patch fix it by exiting nohz idle balance before set cpu offline.
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com>
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 94732d1..7c83f99 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7412,6 +7412,7 @@ int sched_cpu_dying(unsigned int cpu)
/* Handle pending wakeups and then migrate everything off */
sched_ttwu_pending();
+ nohz_balance_exit_idle(cpu);
raw_spin_lock_irqsave(&rq->lock, flags);
if (rq->rd) {
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
@@ -7422,7 +7423,6 @@ int sched_cpu_dying(unsigned int cpu)
raw_spin_unlock_irqrestore(&rq->lock, flags);
calc_load_migrate(rq);
update_max_interval();
- nohz_balance_exit_idle(cpu);
hrtick_clear(rq);
return 0;
}
--
1.9.1
