From: Andrew Morton <akpm@linux-foundation.org>
To: ackerleytng@google.com
Cc: Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org>,
Alex Shi <alexs@kernel.org>, David Hildenbrand <david@kernel.org>,
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stable@vger.kernel.org
Subject: Re: [PATCH v2 0/4] Fix HugeTLB subpool used_hpages tracking
Date: Wed, 9 Sep 2026 15:50:03 -0700 [thread overview]
Message-ID: <20260909155003.e6c2f4fe3c0bbee3b34578fd@linux-foundation.org> (raw)
In-Reply-To: <20260909-hugetlb-subpool-always-track-used-v2-0-30c5d83b572a@google.com>
On Wed, 09 Sep 2026 14:49:25 -0700 Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org> wrote:
> HugeTLB subpools currently only track used_hpages when the user configures
> a size limit.
>
> This is buggy since when there are existing allocations from the subpool
> that would have satisfied the minimum reservations,
> hugepage_subpool_put_pages() will still restore a reservation to the
> subpool. See below for an example of a false reservation.
That sounds annoying, although isn't clear how this affects end-users.
> In addition, the subpool is considered free prematurely, is freed, and this
> ends up causing a use-after-free.
That sounds alarming.
Do you think it's best for us to submit [1-3] for -stable backporting?
Is it feasible to come up with a set of small little fixes to get
-stable out of trouble and then to prepare broader updates for our
ongoing mainline development?
If it's "shut up Andrew you're always saying that" then OK, I can take
that :)
prev parent reply other threads:[~2026-09-09 22:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 21:49 Ackerley Tng via B4 Relay
2026-09-09 21:49 ` [PATCH v2 1/4] mm: hugetlb: Track used_hpages when getting/putting pages from subpool Ackerley Tng via B4 Relay
2026-09-11 14:08 ` Joshua Hahn
2026-09-09 21:49 ` [PATCH v2 2/4] mm: hugetlb: Fix out_put_pages subpool reserve calculation Ackerley Tng via B4 Relay
2026-09-11 14:37 ` Joshua Hahn
2026-09-09 21:49 ` [PATCH v2 3/4] mm: hugetlb: Fix subpool usage leak on allocation failure Ackerley Tng via B4 Relay
2026-09-09 22:54 ` Andrew Morton
2026-09-10 19:57 ` Joshua Hahn
2026-09-11 14:45 ` Joshua Hahn
2026-09-09 21:49 ` [PATCH v2 4/4] mm: hugetlb: Avoid re-allocating global reservations on region add failure Ackerley Tng via B4 Relay
2026-09-11 14:49 ` Joshua Hahn
2026-09-09 22:50 ` Andrew Morton [this message]
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