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Tue, 11 Nov 2025 23:24:32 -0800 (PST) Received: from gmail.com ([117.147.73.250]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7b811183c77sm903311b3a.20.2025.11.11.23.24.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Nov 2025 23:24:31 -0800 (PST) From: peng8420.li@gmail.com To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: david@redhat.com, osalvador@suse.de, jgg@ziepe.ca, jhubbard@nvidia.com, peterx@redhat.com, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, "peng8420.li" Subject: [PATCH] mm/gup: fix handling of zero page in follow_page_pte() Date: Wed, 12 Nov 2025 15:24:24 +0800 Message-ID: <20251112072424.125514-1-peng8420.li@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "peng8420.li" In some scenarios, `__vm_normal_page` might return NULL. In this case, if `is_zero_pfn(pte_pfn(pte))` is true, simply return `page = =3D pte_page(pte)`; no further folio processing is needed. Signed-off-by: peng8420.li --- mm/gup.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/gup.c b/mm/gup.c index 95d948c8e86c..60ae5f0c20e0 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -838,6 +838,7 @@ static struct page *follow_page_pte(struct vm_area_stru= ct *vma, =20 if (is_zero_pfn(pte_pfn(pte))) { page =3D pte_page(pte); + goto out; } else { ret =3D follow_pfn_pte(vma, address, ptep, flags); page =3D ERR_PTR(ret); --=20 2.43.0