From: Andrew Morton <akpm@linux-foundation.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: Kiryl Shutsemau <kas@kernel.org>,
Lance Yang <lance.yang@linux.dev>,
ziy@nvidia.com, baolin.wang@linux.alibaba.com,
liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com,
dev.jain@arm.com, baohua@kernel.org, usama.arif@linux.dev,
ljs@kernel.org, surenb@google.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 1/1] mm/huge_memory: fix pgtable withdrawal for huge zero PMDs
Date: Mon, 14 Sep 2026 11:19:40 -0700 [thread overview]
Message-ID: <20260914111940.f7e2c72eac4a2df97a646793@linux-foundation.org> (raw)
In-Reply-To: <f76beaf8-351a-4b22-b362-a945a5e1af6a@kernel.org>
On Mon, 14 Sep 2026 16:29:00 +0200 "David Hildenbrand (Arm)" <david@kernel.org> wrote:
> On 9/14/26 12:59, Kiryl Shutsemau wrote:
> > On Sun, Sep 13, 2026 at 03:23:12PM +0800, Lance Yang wrote:
> >>
> >> On Sat, Sep 12, 2026 at 11:46:35PM -0700, Andrew Morton wrote:
> >>>
> >>>
> >>> That's the sort of thing we'd prefer to avoid.
> >>>
> >>>
> >>> How real is this? Is there a reported-by:? Do you have a reproducer?
> >>
> >> Yes, I reproduced it on x86 with a small test module. It sets
> >> VM_MIXEDMAP | VM_HUGEPAGE and calls vmf_insert_pfn_pmd() with
> >> huge_zero_pfn, without touching the page tables directly. A full-PMD
> >> munmap() crashes before the split series[1] as well.
> >
> > Ah. So there's no real bug upstream, right?
>
> Matches my understanding.
Thanks. I'll remove cc:stable, move this into mm-unstable as a
next-merge-window thing.
next prev parent reply other threads:[~2026-09-14 18:19 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-13 5:19 Lance Yang
2026-09-13 6:46 ` Andrew Morton
2026-09-13 7:23 ` Lance Yang
2026-09-14 10:59 ` Kiryl Shutsemau
2026-09-14 14:29 ` David Hildenbrand (Arm)
2026-09-14 18:19 ` Andrew Morton [this message]
2026-09-15 13:43 ` Lance Yang
2026-09-15 13:52 ` Kiryl Shutsemau
2026-09-15 15:03 ` David Hildenbrand (Arm)
2026-09-15 15:13 ` David Hildenbrand (Arm)
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