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Date:   Thu, 21 Mar 2019 22:46:08 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Daniel Bristot de Oliveira <bristot@redhat.com>
Cc:     linux-rt-users <linux-rt-users@vger.kernel.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Clark Williams <williams@redhat.com>,
        Tommaso Cucinotta <tommaso.cucinotta@sssup.it>,
        =?iso-8859-1?Q?R=F4mulo?= Silva de Oliveira 
        <romulo.deoliveira@ufsc.br>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: BUG-RT: scheduling while in atomic in the watchdog's hrtimer
Message-ID: <20190321214608.GE7905@worktop.programming.kicks-ass.net>
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On Thu, Mar 21, 2019 at 10:27:30PM +0100, Daniel Bristot de Oliveira wrote:
> Hi,
> 
> In the 4.19/5.0-rt configured !SMP, the following chain of events can
> take place:
> 
> ------------------------------ %< -------------------------------------
> smp_apic_timer_interrupt(){
> 	hrtimer_interrupt() {
> 		__hrtimer_run_queues() {
> 			watchdog_timer_fn() {
> 				stop_one_cpu_nowait() {
> 					#ifdef !CONFIG_SMP

ARGGHH..