hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9VPMT

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Remove warn printk for checking 'rq->tmp_alone_branch != &rq->leaf_cfs_rq_list' to avoid rq deadlock.

Deadlock analaze: cpu 0

distribute_cfs_runtime --- rq_lock_irqsave(rq, &rf); ->__warn_printk ->try_to_wake_up --- rq_lock(rq, &rf), deadlock

Call Trace: queued_spin_lock_slowpath at ffff000080173358 try_to_wake_up at ffff000080141068 wake_up_process at ffff00008014113c insert_work at ffff000080123750 __queue_work at ffff0000801257ac queue_work_on at ffff000080125c54 drm_fb_helper_dirty at ffff0000806dcd44 drm_fb_helper_sys_imageblit at ffff0000806dcf04 virtio_gpu_3d_imageblit at ffff000000c915d0 [virtio_gpu] soft_cursor at ffff0000805e3e04 bit_cursor at ffff0000805e3654 fbcon_cursor at ffff0000805df404 hide_cursor at ffff000080677d68 vt_console_print at ffff0000806799dc console_unlock at ffff000080183d78 vprintk_emit at ffff000080185948 vprintk_default at ffff000080185b80 vprintk_func at ffff000080186c44 printk at ffff000080186394 __warn_printk at ffff000080102d60 unthrottle_cfs_rq at ffff000080155e50 distribute_cfs_runtime at ffff00008015617c sched_cfs_period_timer at ffff00008015654c __hrtimer_run_queues at ffff0000801b2c58 hrtimer_interrupt at ffff0000801b3c74 arch_timer_handler_virt at ffff00008089dc3c handle_percpu_devid_irq at ffff00008018fb3c generic_handle_irq at ffff000080187140 __handle_domain_irq at ffff000080187adc gic_handle_irq at ffff000080081814

Signed-off-by: Hui Tang tanghui20@huawei.com --- kernel/sched/fair.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3bd5aa6dedb3..3f6dc69d68fb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -395,7 +395,9 @@ static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)

static inline void assert_list_leaf_cfs_rq(struct rq *rq) { - SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list); + /* There are possible rq deadlock when warn is triggered, + * since try_to_wake_up may called by __warn_printk. + */ }

/* Iterate thr' all leaf cfs_rq's on a runqueue */