From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nbI8s-00DrYA-0x for linux-um@lists.infradead.org; Mon, 04 Apr 2022 08:32:57 +0000 From: Thomas Gleixner Subject: Re: UML time-travel warning from __run_timers In-Reply-To: References: <20220330110156.GA9250@axis.com> <84f9d627092660c38400b607198c3b83f795be7f.camel@sipsolutions.net> <877d86m978.ffs@tglx> <32423b7c0e3a490093ceaca750e8669ac67902c6.camel@sipsolutions.net> <87pmlykksj.ffs@tglx> Date: Mon, 04 Apr 2022 10:32:46 +0200 Message-ID: <87ee2dl041.ffs@tglx> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Johannes Berg , Vincent Whitchurch Cc: linux-um@lists.infradead.org, linux-kernel@vger.kernel.org, Anna-Maria Gleixner , Frederic Weisbecker On Mon, Apr 04 2022 at 09:02, Johannes Berg wrote: > On Sun, 2022-04-03 at 21:51 +0200, Thomas Gleixner wrote: >> but that's fine and it is overwritten by every timer which is inserted >> to expire before that. So that's not an issue as the prandom timer is >> firing and rearmed. > > No, as I said before, there's never any timer with base 1 (BASE_DEF) in > the config we have. The prandom timer is not TIMER_DEFERRABLE (it > probably could be, but it's not now). There's no deferrable timer at > all. Once there is at least one, the warning goes away. Groan. I overlooked the deferrable part. Yes, you are right. next_expiry of the deferrable base is stale when there is no timer queued up to the point where base->clk reaches the initial next_expiry value. So the check is bogus. Thanks, tglx --- --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1724,9 +1724,8 @@ static inline void __run_timers(struct t /* * The only possible reason for not finding any expired * timer at this clk is that all matching timers have been - * dequeued. + * dequeued or no timer has been ever queued. */ - WARN_ON_ONCE(!levels && !base->next_expiry_recalc); base->clk++; base->next_expiry = __next_timer_interrupt(base); _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um