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The warning is triggered by simply starting the machine, mounting debugfs and then just zeroing any fair-server's runtime. The warning: WARNING: kernel/sched/deadline.c:266 at dl_rq_change_utilization+0x208/0x230 static inline void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) { ... WARN_ON_ONCE(dl_rq->running_bw > dl_rq->this_bw); } Steps to reproduce: mount -t debugfs none /sys/kernel/debug echo 0 > /sys/kernel/debug/sched/fair_server/cpu0/runtime It does not happen at every machine boot, but happens on most. Could it possibly be related to some of the deadline timers? I'll probably follow up with some more tests to better understand what is going on but I first wanted to bring this up. Have a nice day, Yuri