From: Andrew Morton <akpm@linux-foundation.org>
To: Chris Mason <clm@meta.com>
Cc: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: Re: [PATCH] percpu: add basic double free check
Date: Thu, 15 Jan 2026 15:13:28 -0800 [thread overview]
Message-ID: <20260115151328.38cc7cf0d0b8bf97ee5b3791@linux-foundation.org> (raw)
In-Reply-To: <20260114122209.1075584-1-clm@meta.com>
On Wed, 14 Jan 2026 04:22:00 -0800 Chris Mason <clm@meta.com> wrote:
> On Fri, 19 Dec 2025 16:27:37 -0800 Dennis Zhou <dennis@kernel.org> wrote:
>
> > This adds a basic double free check by validating the first bit of the
> > allocation in alloc_map and bound_map are set. If the alloc_map bit is
> > not set, then this means the area is currently unallocated. If the
> > bound_map bit is not set, then we are not freeing from the beginning of
> > the allocation.
>
> Hi Dennis,
>
> I ran mm-new through the AI review prompts, and this one was flagged:
So good.
> If nr_alloc is underreported due to this bug, the buffer may be undersized
> for the actual number of allocations tracked in alloc_map, which
> chunk_map_stats() iterates based on the actual bitmap contents.
That's pretty serious, although unlikely to occur. I'll drop this
version of the patch, thanks.
next prev parent reply other threads:[~2026-01-15 23:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-20 0:27 Dennis Zhou
2026-01-12 16:03 ` Sebastian Andrzej Siewior
2026-01-14 12:22 ` Chris Mason
2026-01-15 23:13 ` Andrew Morton [this message]
2026-01-16 2:56 ` Dennis Zhou
2026-01-16 2:38 ` Dennis Zhou
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