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From:   John Ogness <john.ogness@linutronix.de>
To:     Pierre Gondois <pierre.gondois@arm.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        linux-rt-users@vger.kernel.org,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [ANNOUNCE] v6.3-rc2-rt3
In-Reply-To: <9ee941ae-ae22-f14b-4e69-f81b29bbba4b@arm.com>
References: <20230314170502.OHw1_FK3@linutronix.de>
 <20230314171231.jwtham4a@linutronix.de>
 <9ee941ae-ae22-f14b-4e69-f81b29bbba4b@arm.com>
Date:   Fri, 14 Apr 2023 15:55:50 +0206
Message-ID: <87ttxiefpd.fsf@jogness.linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Hi Pierre,

On 2023-04-14, Pierre Gondois <pierre.gondois@arm.com> wrote:
> =============================
> [ BUG: Invalid wait context ]
> 6.3.0-rc5-rt8-gacb52bd349a2 #417 Not tainted
> -----------------------------
> swapper/0/1 is trying to lock:
> ffff00097eea1180 (cpu){....}-{3:3}, at: __printk_safe_enter (kernel/printk/printk_safe.c:28 (discriminator 3))
> other info that might help us debug this:
> context-{5:5}
> 1 lock held by swapper/0/1:
> #0: ffff80000ba77028 (rcu_tasks_rude.cbs_gbl_lock){....}-{2:2}, at: cblist_init_generic (kernel/rcu/tasks.h:233)

This is actually a mainline issue relating to legacy consoles. In
mainline you see it as a warning when CONFIG_PROVE_RAW_LOCK_NESTING is
enabled.

If you enable CONFIG_PREEMPT_RT you will not have the problem.

I will look at how the issue can be gracefully ignored in
!CONFIG_PREEMPT_RT.

Thanks for reporting.

John Ogness