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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
Date: Wed, 24 Jun 2026 17:46:42 -0700	[thread overview]
Message-ID: <20260624174642.da2cc6912a9b19accd378538@linux-foundation.org> (raw)
In-Reply-To: <20260622154216.10064-1-include@grrlz.net>

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.



      reply	other threads:[~2026-06-25  0:46 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-22 15:42 Bradley Morgan
2026-06-25  0:46 ` Andrew Morton [this message]

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