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Date: Wed, 24 Jun 2026 17:46:42 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Bradley Morgan <include@grrlz.net>
Cc: Kees Cook <kees@kernel.org>, Matteo Croce <mcroce@microsoft.com>,
 linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] reboot: keep parsed reboot CPU in range
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On Mon, 22 Jun 2026 15:42:16 +0000 Bradley Morgan <include@grrlz.net> wrote:

> reboot=s... parses the CPU number with simple_strtoul(), but stores
> it in an int before checking it against num_possible_cpus(). Very
> large values can wrap negative and bypass the range check, leaving
> reboot_cpu invalid for migrate_to_reboot_cpu().

Thanks.  kstrtoXX() is the modern way.

> Keep the parsed value unsigned until after the range check.
> 
> Fixes: f9a90501faac ("reboot: refactor and comment the cpu selection code")
> Cc: stable@vger.kernel.org

I don't think this is serious enough to warrant backporting.