From: Andrew Morton <akpm@linux-foundation.org>
To: Pimyn Girgis <pimyn@google.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
elver@google.com, dvyukov@google.com, glider@google.com,
kasan-dev@googlegroups.com, stable@vger.kernel.org
Subject: Re: [PATCH] mm/kfence: randomize the freelist on initialization
Date: Tue, 20 Jan 2026 09:46:17 -0800 [thread overview]
Message-ID: <20260120094617.ed5a53e9ec40e8f0a91f8cb6@linux-foundation.org> (raw)
In-Reply-To: <20260120161510.3289089-1-pimyn@google.com>
On Tue, 20 Jan 2026 17:15:10 +0100 Pimyn Girgis <pimyn@google.com> wrote:
> Randomize the KFENCE freelist during pool initialization to make allocation
> patterns less predictable. This is achieved by shuffling the order in which
> metadata objects are added to the freelist using get_random_u32_below().
>
> Additionally, ensure the error path correctly calculates the address range
> to be reset if initialization fails, as the address increment logic has
> been moved to a separate loop.
>
> Cc: stable@vger.kernel.org
> Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
It isn't clear (to me) what was wrong with 0ce20dd84089, nor why a
-stable backport is proposed.
Can we please have a full description of the current misbehavior? What
are the worst-case userspace-visible effects of this flaw?
next prev parent reply other threads:[~2026-01-20 17:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 16:15 Pimyn Girgis
2026-01-20 17:46 ` Andrew Morton [this message]
2026-01-23 17:13 ` Alexander Potapenko
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