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Sat, 21 Mar 2026 06:29:22 -0700 (PDT) Received: from kernel-devel.tail62cea.ts.net ([240d:1a:c0d:9f00:be24:11ff:fe35:71b3]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35bc610db9asm7957406a91.15.2026.03.21.06.29.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Mar 2026 06:29:22 -0700 (PDT) From: Shigeru Yoshida To: Minchan Kim , Sergey Senozhatsky , Andrew Morton , Mark-PK Tsai Cc: Shigeru Yoshida , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/zsmalloc: copy KMSAN metadata in zs_page_migrate() Date: Sat, 21 Mar 2026 22:29:11 +0900 Message-ID: <20260321132912.93434-1-syoshida@redhat.com> X-Mailer: git-send-email 2.52.0 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" zs_page_migrate() uses copy_page() to copy the contents of a zspage page during migration. However, copy_page() is not instrumented by KMSAN, so the shadow and origin metadata of the destination page are not updated. As a result, subsequent accesses to the migrated page are reported as use-after-free by KMSAN, despite the data being correctly copied. Add a kmsan_copy_page_meta() call after copy_page() to propagate the KMSAN metadata to the new page, matching what copy_highpage() does internally. Fixes: afb2d666d025 ("zsmalloc: use copy_page for full page copy") Signed-off-by: Shigeru Yoshida --- mm/zsmalloc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 2c1430bf8d57..79ef9d57f2e1 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1741,6 +1741,7 @@ static int zs_page_migrate(struct page *newpage, stru= ct page *page, */ d_addr =3D kmap_local_zpdesc(newzpdesc); copy_page(d_addr, s_addr); + kmsan_copy_page_meta(zpdesc_page(newzpdesc), zpdesc_page(zpdesc)); kunmap_local(d_addr); =20 for (addr =3D s_addr + offset; addr < s_addr + PAGE_SIZE; --=20 2.52.0