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charset="utf-8" Enabling NEXT_BUDDY triggers warning, and rcu stall: [ 124.977300] cfs_rq->next->sched_delayed [ 124.977310] WARNING: CPU: 51 PID: 2150 at kernel/sched/fair.c:5621 pick_= task_fair+0x130/0x150 [ 125.049547] CPU: 51 UID: 0 PID: 2150 Comm: kworker/51:1 Tainted: G = E 6.12.0.adam+ #1 [ 125.163561] Call trace: [ 125.165996] pick_task_fair+0x130/0x150 (P) [ 125.170167] pick_task_fair+0x130/0x150 (L) [ 125.174338] pick_next_task_fair+0x48/0x3c0 [ 125.178512] __pick_next_task+0x4c/0x220 [ 125.182426] pick_next_task+0x44/0x980 [ 125.186163] __schedule+0x3d0/0x628 [ 125.189645] schedule+0x3c/0xe0 [ 125.192776] worker_thread+0x1a4/0x368 [ 125.196516] kthread+0xfc/0x110 [ 125.199647] ret_from_fork+0x10/0x20 [ 125.203213] ---[ end trace 0000000000000000 ]--- [ 211.151849] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 211.159759] rcu: (detected by 141, t=3D15003 jiffies, g=3D5629, q=3D= 26516 ncpus=3D384) Do not set next buddy if sched_delayed is set. Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue") Signed-off-by: Adam Li --- kernel/sched/fair.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index fbdca89c677f..cd1188b7f3df 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8748,6 +8748,8 @@ static void set_next_buddy(struct sched_entity *se) return; if (se_is_idle(se)) return; + if (se->sched_delayed) + return; cfs_rq_of(se)->next =3D se; } } --=20 2.25.1