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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LX9oQFb3JCU/nRh3HOHfyGm75yvY2AqOJkXgl4H1OUrL+YV/yfv5t2j4NyOmkDQk9 wJjiz2smZNW3BasgYXW2q2tqg9DtW18Hjbi6WScVSvfUxSgq2xS9N/BwOrfVKoiH+i KRo062zN72Uh7zYRswDgomQDOFjW4Mykh8WDYZzM= Date: Tue, 27 Oct 2026 17:06:11 +0000 From: Catalin Marinas To: Muchun Song Cc: Andrew Morton , David Hildenbrand , Oscar Salvador , Dave Hansen , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Will Deacon , Mark Rutland , Kevin Brodsky , Alexander Gordeev , Alistair Popple , linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Muchun Song Subject: Re: [PATCH v3 4/4] arm64/mm: fix destructor for unconstructed hotplug page tables Message-ID: References: <20261023063428.3658761-1-songmuchun@bytedance.com> <20261023063428.3658761-5-songmuchun@bytedance.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261023063428.3658761-5-songmuchun@bytedance.com> X-Rspamd-Queue-Id: 3B7FF40004 X-Rspam-User: X-Stat-Signature: 8xqgkuq5hiath7qf5gmi9jp6iufbzxk9 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793120777-305641 X-HE-Meta: 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 AWGJDMos AnGqfuGQitaKljxm4e+DySSh1luHzTqq8NapuKjOFGpkG6i6fWKZWpjAEOn9rnUqzJEty3FkpdG5WcQehhze4ycT0ffXDDKTWUAFkEU7P1clsrmtAJwn0qCvYv9AN19dPyqU6fgVSlvyytIrwPNpdZGbEyq+tIg/oGPWCJxjWuEmSaFkscD9FUyGnjCnS1cJPl3Q48tnBZ18RcSODpr3DbA5r8mK5YH+L64WhQigjK9M9d/YuE3k4TOLHTO9OcyoFIJO9qHwiplBaIdAQVoHeQaasHr1YX6B0jyuPQbHNpLGpPL4U+A0vyliE1ET4srEdIXmFAMSE8yQ/3zkNZ8H/7WpTkg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Fri, Oct 23, 2026 at 02:34:28PM +0800, Muchun Song wrote: > Commit c594b83457cc ("arm64: mm: call pagetable dtor when freeing > hot-removed page tables") made free_hotplug_pgtable_page() > unconditionally run the page-table destructor. This matches page tables > allocated by the arm64 mapping code, which runs the corresponding > constructors. > > However, arm64 also uses the generic sparse-vmemmap population code. > Runtime intermediate page tables allocated by that code do not run a > page-table constructor. Freeing one during memory hot-remove therefore > runs a destructor without a matching constructor and corrupts > NR_PAGETABLE accounting. > > Free intermediate page-table pages through pagetable_free(). It runs the > destructor only for constructor-backed pages and then releases the page > through the page-table freeing path. > > Fixes: c594b83457cc ("arm64: mm: call pagetable dtor when freeing hot-removed page tables") > Cc: stable@vger.kernel.org > Assisted-by: LLM > Signed-off-by: Muchun Song > Reviewed-by: Kevin Brodsky > Acked-by: David Hildenbrand (Arm) Reviewed-by: Catalin Marinas