Hi, On 06/03/17 21:51, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > > The following warning can be triggered by hot-unplugging the CPU > on which an active SCHED_DEADLINE task is running on: > > ------------[ cut here ]------------ > WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40 > rq->clock_update_flags < RQCF_ACT_SKIP > CPU: 7 PID: 0 Comm: swapper/7 Tainted: G B 4.11.0-rc1+ #24 > Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 > Call Trace: > <IRQ> > dump_stack+0x85/0xc4 > __warn+0x172/0x1b0 > warn_slowpath_fmt+0xb4/0xf0 > ? __warn+0x1b0/0x1b0 > ? debug_check_no_locks_freed+0x2c0/0x2c0 > ? cpudl_set+0x3d/0x2b0 > replenish_dl_entity+0x71e/0xc40 > enqueue_task_dl+0x2ea/0x12e0 > ? dl_task_timer+0x777/0x990 > ? __hrtimer_run_queues+0x270/0xa50 > dl_task_timer+0x316/0x990 > ? enqueue_task_dl+0x12e0/0x12e0 > ? enqueue_task_dl+0x12e0/0x12e0 > __hrtimer_run_queues+0x270/0xa50 > ? hrtimer_cancel+0x20/0x20 > ? hrtimer_interrupt+0x119/0x600 > hrtimer_interrupt+0x19c/0x600 > ? trace_hardirqs_off+0xd/0x10 > local_apic_timer_interrupt+0x74/0xe0 > smp_apic_timer_interrupt+0x76/0xa0 > apic_timer_interrupt+0x93/0xa0 > > The DL task will be migrated to a suitable later deadline rq once the DL > timer fires and currnet rq is offline. The rq clock of the new rq should > be updated. This patch fixes it by updating the rq clock after holding > the new rq's rq lock. > > Cc: Juri Lelli <juri.lelli@xxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > --- > kernel/sched/deadline.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 99b2c33..c6db3fd 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) > lockdep_unpin_lock(&rq->lock, rf.cookie); > rq = dl_task_offline_migration(rq, p); > rf.cookie = lockdep_pin_lock(&rq->lock); > + update_rq_clock(rq); Looks good to me. Acked-by: Juri Lelli <juri.lelli@xxxxxxx> Thanks, - Juri
