Hi Vincent,
> [10737482.720000][ C0] ------------[ cut here ]------------ > [10737482.720000][ C0] WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1729 > __run_timers+0x36d/0x380 > [for those new on the thread, full message and config here: https://lore.kernel.org/r/20220330110156.ga9...@axis.com] I think maybe you found a bug in the timers code? Your config has CONFIG_NO_HZ_COMMON, so we have both BASE_STD and BASE_DEF. Evidently, in your config, we *never* have any timer with TIMER_DEFERRABLE, which would put it into BASE_DEF. (I put a WARN_ON into get_timer_cpu_base() and get_timer_this_cpu_base() in the if, and it never triggered; I guess my config has something that creates a deferrable timer, so it didn't trigger, but I didn't check that now.) Therefore, base->next_expiry never changes or something? At init, we get init_timer_cpu(0) base 0 clk=0xffff8ad0, next_expiry=0x13fff8acf init_timer_cpu(0) base 1 clk=0xffff8ad0, next_expiry=0x13fff8acf which makes sense, jiffies is set up to wrap very quickly after boot. The warning triggers when we have jiffies=0x13fff9600, so it's just after the "next_expiry", so in this code: static inline void __run_timers(struct timer_base *base) { struct hlist_head heads[LVL_DEPTH]; int levels; if (time_before(jiffies, base->next_expiry)) return; we no longer return. Previously, we've *never* executed past that if for BASE_DEF. But we never touched this timer base nor did we ever want to recalc it I guess, so WARN_ON_ONCE(!levels && !base->next_expiry_recalc); triggers. I thought about changing that condition to if (time_before(...) || !base->timers_pending) return; and that *does* make the splat go away, but I fear that might make it not recalculate when needed, so perhaps in the condition we should have if (time_before(...) || (!base->timers_pending && !base->next_expiry_recalc)) return; or something? (which also avoids hitting the warning) But I really don't know anything about this code, so adding a few CCs. Can you help? Thanks, johannes _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um
