Re: [RESEND PATCH] irqchip/irq-mtk-sysirq: replace spinlock with raw_spinlock

From: Marc Zyngier <maz@kernel.org>
To: Jason Cooper <jason@lakedaemon.net>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Perepech <andrew.perepech@mediatek.com>,
	linux-mediatek@lists.infradead.org,
	Stephane Le Provost <stephane.leprovost@mediatek.com>,
	linux-arm-kernel@lists.infradead.org,
	Pedro Tsai <pedro.tsai@mediatek.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Fabien Parent <fparent@baylibre.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RESEND PATCH] irqchip/irq-mtk-sysirq: replace spinlock with raw_spinlock
Date: Sat, 27 Jun 2020 12:08:01 +0100	[thread overview]
Message-ID: <159325548742.93134.3774851842783687845.b4-ty@kernel.org> (raw)
In-Reply-To: <20200615074445.3579-1-brgl@bgdev.pl>

On Mon, 15 Jun 2020 09:44:45 +0200, Bartosz Golaszewski wrote:
> This driver may take a regular spinlock when a raw spinlock
> (irq_desc->lock) is already taken which results in the following
> lockdep splat:
> 
> =============================
> [ BUG: Invalid wait context ]
> 5.7.0-rc7 #1 Not tainted
> -----------------------------
> swapper/0/0 is trying to lock:
> ffffff800303b798 (&chip_data->lock){....}-{3:3}, at: mtk_sysirq_set_type+0x48/0xc0
> other info that might help us debug this:
> context-{5:5}
> 2 locks held by swapper/0/0:
>  #0: ffffff800302ee68 (&desc->request_mutex){....}-{4:4}, at: __setup_irq+0xc4/0x8a0
>  #1: ffffff800302ecf0 (&irq_desc_lock_class){....}-{2:2}, at: __setup_irq+0xe4/0x8a0
> stack backtrace:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-rc7 #1
> Hardware name: Pumpkin MT8516 (DT)
> Call trace:
>  dump_backtrace+0x0/0x180
>  show_stack+0x14/0x20
>  dump_stack+0xd0/0x118
>  __lock_acquire+0x8c8/0x2270
>  lock_acquire+0xf8/0x470
>  _raw_spin_lock_irqsave+0x50/0x78
>  mtk_sysirq_set_type+0x48/0xc0
>  __irq_set_trigger+0x58/0x170
>  __setup_irq+0x420/0x8a0
>  request_threaded_irq+0xd8/0x190
>  timer_of_init+0x1e8/0x2c4
>  mtk_gpt_init+0x5c/0x1dc
>  timer_probe+0x74/0xf4
>  time_init+0x14/0x44
>  start_kernel+0x394/0x4f0
> 
> [...]

Applied to irq/irqchip-5.9:

[1/1] irqchip/irq-mtk-sysirq: Replace spinlock with raw_spinlock
      commit: 6eeb997ab5075e770a002c51351fa4ec2c6b5c39

Thanks,

	M.
-- 
Without deviation from the norm, progress is not possible.