From: Thomas Gleixner <tglx@linutronix.de>
To: Sergey Shtylyov <s.shtylyov@omp.ru>,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] irqchip/gic: prevent buffer overflow in gic_ipi_send_mask()
Date: Thu, 05 Sep 2024 09:29:32 +0200 [thread overview]
Message-ID: <87cyli5zj7.ffs@tglx> (raw)
In-Reply-To: <048ff3bb-09d1-2e60-4f3b-611e2bfde7aa@omp.ru>
On Wed, Sep 04 2024 at 23:23, Sergey Shtylyov wrote:
> ARM GIC arch v2 spec claims support for just 8 CPU interfaces. However,
> looking at the GIC driver's irq_set_affinity() method, it seems that the
> passed CPU mask may contain the logical CPU #s beyond 8, and that method
> filters them out before reading gic_cpu_map[], bailing out with
> -EINVAL.
The reasoning is correct in theory, but in reality it's a non problem.
Simply because processors which use this GIC version cannot have more
than 8 cores.
That means num_possible_cpus() <= 8 so the cpumask handed in cannot have
bits >= 8 set. Ergo for_each_cpu() can't return a bit which is >= 8.
Thanks
tglx
next prev parent reply other threads:[~2024-09-05 7:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-04 20:23 [PATCH] irqchip/gic: prevent buffer overflow in gic_ipi_send_mask() Sergey Shtylyov
2024-09-05 7:29 ` Thomas Gleixner [this message]
2024-09-05 7:47 ` Marc Zyngier
2024-09-06 20:29 ` Sergey Shtylyov
2024-09-06 20:36 ` Sergey Shtylyov
2024-09-08 9:37 ` Marc Zyngier
2024-09-09 19:48 ` Sergey Shtylyov
2024-09-10 7:38 ` Marc Zyngier
2024-09-09 19:23 ` Sergey Shtylyov
2024-09-10 7:50 ` Marc Zyngier
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