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References: <20240529215458.937817-1-samuel.holland@sifive.com>
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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 30 May 2024 09:13:23 +0200
Message-ID: <CAMuHMdVLgpxPCK0chTY=GvMVPgF5G1Oyj=XXoJZBORvH5shFxQ@mail.gmail.com>
Subject: Re: [PATCH] irqchip/sifive-plic: Chain to parent IRQ after handlers
 are ready
To: Samuel Holland <samuel.holland@sifive.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Albert Ou <aou@eecs.berkeley.edu>, 
	Anup Patel <apatel@ventanamicro.com>, Palmer Dabbelt <palmer@dabbelt.com>, 
	Paul Walmsley <paul.walmsley@sifive.com>, linux-kernel@vger.kernel.org, 
	linux-riscv@lists.infradead.org
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Hi Samuel,

On Wed, May 29, 2024 at 11:55=E2=80=AFPM Samuel Holland
<samuel.holland@sifive.com> wrote:
> Now that the PLIC uses a platform driver, the driver probed later in the
> boot process, where interrupts from peripherals might already be
> pending. As a result, plic_handle_irq() may be called as early as the
> call to irq_set_chained_handler(). But this call happens before the
> per-context handler is completely set up, so there is a window where
> plic_handle_irq() can see incomplete per-context state and crash. Avoid
> this by delaying the call to irq_set_chained_handler() until all
> handlers from all PLICs are initialized.
>
> Fixes: 8ec99b033147 ("irqchip/sifive-plic: Convert PLIC driver into a pla=
tform driver")
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Closes: https://lore.kernel.org/r/CAMuHMdVYFFR7K5SbHBLY-JHhb7YpgGMS_hnRWm=
8H0KD-wBo+4A@mail.gmail.com/
> Signed-off-by: Samuel Holland <samuel.holland@sifive.com>

Thanks for your patch!

This fixes the issue I was seering on Starlight, and does not seem to
cause regressions on RZ/Five, Icicle, K210, or VexRiscV.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds