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From: Thomas Gleixner <tglx@kernel.org>
To: Biju <biju.das.au@gmail.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>,
	linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Biju Das <biju.das.au@gmail.com>,
	linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH 3/3] irqchip/renesas-rzg2l: Add NMI support
Date: Tue, 31 Mar 2026 18:15:56 +0200	[thread overview]
Message-ID: <87qzp07z5v.ffs@tglx> (raw)
In-Reply-To: <20260328103324.134131-4-biju.das.jz@bp.renesas.com>

On Sat, Mar 28 2026 at 10:33, Biju wrote:
> +static void rzg2l_irqc_nmi_eoi(struct irq_data *d)
> +{
> +	struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> +	unsigned int hw_irq = irqd_to_hwirq(d);
> +
> +	scoped_guard(raw_spinlock, &priv->lock)
> +		rzg2l_clear_nmi_int(priv, hw_irq);

Is priv is shared between regular interrupts and the NMI?

If so, then you can't take the lock.

    // Some other context (task, interrupt)
    raw_spinlock(priv->lock);

--> NMI

        raw_spinlock(priv->lock);

--> Livelock.

Thanks,

        tglx

  parent reply	other threads:[~2026-03-31 16:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-28 10:33 [PATCH 0/3] irqchip/renesas-rzg2l: Bug fixes and NMI support Biju
2026-03-28 10:33 ` [PATCH 1/3] irqchip/renesas-rzg2l: Fix shared IRQ bit not cleared on free Biju
2026-03-28 10:33 ` [PATCH 2/3] irqchip/renesas-rzg2l: Replace raw_spin_{lock,unlock} with guard() in rzg2l_irq_set_type() Biju
2026-03-28 10:33 ` [PATCH 3/3] irqchip/renesas-rzg2l: Add NMI support Biju
2026-03-28 16:19   ` Wolfram Sang
2026-03-31 17:35     ` Biju Das
2026-03-31 16:15   ` Thomas Gleixner [this message]
2026-03-31 17:10     ` Biju Das
2026-03-31 20:29       ` Thomas Gleixner
2026-04-01  7:30         ` Biju Das
2026-04-01 11:22           ` Thomas Gleixner

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