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Date: Thu, 26 Mar 2026 19:13:58 +0000
From: Dmitry Ilvokhin <d@ilvokhin.com>
To: Thomas Gleixner <tglx@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
	Neil Horman <nhorman@tuxdriver.com>, Radu Rendec <radu@rendec.net>
Subject: Re: [patch v2 09/14] genirq: Expose irq_find_desc_at_or_after() in
 core code
Message-ID: <acWFdtV2FYHEwBZw@shell.ilvokhin.com>
References: <20260320131108.344376329@kernel.org>
 <20260320132102.638201987@kernel.org>
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In-Reply-To: <20260320132102.638201987@kernel.org>

On Fri, Mar 20, 2026 at 02:22:09PM +0100, Thomas Gleixner wrote:
> --- in preparation for a smarter iterator for /proc/interrupts.
> 
> Signed-off-by: Thomas Gleixner <tglx@kernel.org>
> ---
>  kernel/irq/internals.h |    2 ++
>  kernel/irq/irqdesc.c   |   12 +++++-------
>  2 files changed, 7 insertions(+), 7 deletions(-)
> 

[...]

>  
> -static unsigned int irq_find_at_or_after(unsigned int offset)
> +struct irq_desc *irq_find_desc_at_or_after(unsigned int offset)
>  {
>  	unsigned long index = offset;
> -	struct irq_desc *desc;
> -
> -	guard(rcu)();

Is the drop of guard(rcu)() intentional here? irq_get_next_irq()
dereferences the returned pointer after mt_find() has dropped
rcu_read_unlock(). Should it hold its own guard(rcu)() to keep the same
behaviour as before?