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From: Marc Zyngier <maz@kernel.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de
Subject: Re: [irqchip: irq/irqchip-next] irqdomain: Protect the linear revmap with RCU
Date: Tue, 06 Jul 2021 10:24:29 +0100	[thread overview]
Message-ID: <87eecb94mq.wl-maz@kernel.org> (raw)
In-Reply-To: <fb3b9223-a811-af48-ead5-b2c6f7305de4@roeck-us.net>

On Mon, 05 Jul 2021 21:36:36 +0100,
Guenter Roeck <linux@roeck-us.net> wrote:
> 
> On 7/5/21 11:43 AM, Marc Zyngier wrote:

> > It definitely helps, and confirms my hunch. With the patch below, I'm
> > not getting the warnings anymore. I'm pretty sure a number of other
> > MIPS systems suffer from similar issues, which I'll address similarly.
> > 
> > Please let me know if that addresses the issue on your end.
> > 
> 
> Yes, it does. Feel free to add
> 
> Tested-by: Guenter Roeck <linux@roeck-us.net>
> 
> to the real patch.

Thanks.

> Now the big question: Why does this only affect 32-bit little endian
> mips images, but not the matching big endian images, nor 64-bit images ?

Are you sure these images are using the exact same HW? A bunch (most?)
of MIPS systems do not use irqdomains in their root interrupt
handling, so this issue wouldn't be visible (irq_enter() will already
have been done for the chained interrupt handling).

FWIW, I can reproduce the problem by switching your mipsel config to
BE, and adding this patch fixes it.

Thanks,

	M.

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

  reply	other threads:[~2021-07-06  9:24 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-11 13:54 [irqchip: irq/irqchip-next] irqdomain: Protect the linear revmap with RCU irqchip-bot for Marc Zyngier
2021-07-05 17:23 ` Guenter Roeck
2021-07-05 18:01   ` Marc Zyngier
2021-07-05 18:23     ` Guenter Roeck
2021-07-05 18:43       ` Marc Zyngier
2021-07-05 20:36         ` Guenter Roeck
2021-07-06  9:24           ` Marc Zyngier [this message]
2021-07-06 14:23             ` Guenter Roeck
2021-07-08  8:00   ` [irqchip: irq/irqchip-fixes] irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry irqchip-bot for Marc Zyngier
2021-07-09  9:23   ` irqchip-bot for Marc Zyngier
  -- strict thread matches above, loose matches on Subject: below --
2021-06-06 12:43 [irqchip: irq/irqchip-next] irqdomain: Protect the linear revmap with RCU irqchip-bot for Marc Zyngier

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