This is a note to let you know that I've just added the patch titled

sched/deadline: Add missing update_rq_clock() in dl_task_timer()

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sched-deadline-add-missing-update_rq_clock-in-dl_task_timer.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Mon Dec 18 14:12:34 CET 2017

From: Wanpeng Li wanpeng.li@hotmail.com Date: Mon, 6 Mar 2017 21:51:28 -0800 Subject: sched/deadline: Add missing update_rq_clock() in dl_task_timer()

From: Wanpeng Li wanpeng.li@hotmail.com

[ Upstream commit dcc3b5ffe1b32771c9a22e2c916fb94c4fcf5b79 ]

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.

Signed-off-by: Wanpeng Li wanpeng.li@hotmail.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Matt Fleming matt@codeblueprint.co.uk Cc: Juri Lelli juri.lelli@arm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Mike Galbraith efault@gmx.de Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/1488865888-15894-1-git-send-email-wanpeng.li@hotmai... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/deadline.c | 1 + 1 file changed, 1 insertion(+)

--- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_time 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);

/* * Now that the task has been migrated to the new RQ and we

Patches currently in stable-queue which might be from wanpeng.li@hotmail.com are

queue-4.9/sched-deadline-add-missing-update_rq_clock-in-dl_task_timer.patch