From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 435DB22258C for ; Sun, 7 Sep 2025 22:26:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757283985; cv=none; b=llBPWc77FDB+RH2Ev8YfANtQU+GcMlWFDj7fZYw+TwXKWZNMNuUmb0oRedd097S8lIJ1tiD/Ovuu7qLn07xJQPEqgygf3nxRWI/48l6gqz9bk02r2BVeqfURs5pQUDv8n+P40ke5wbjD64ATr8bHx3OrmB99XBWGjNruXOu+2pc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757283985; c=relaxed/simple; bh=iTdczuKyxSrJYzwFcLxO9GNAlg2euIKIYd6uKrGA2X0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=feNzHj3tlkpCcqtoswt6LmQrYXuP8bOkiQhzNpBkUTpf4/Nze5Fj9ExNI5gPGLJg2u1ukUX6D1/hLxZ92VThVZgKjgI9z3ivRbSHuuqPIzUWGz0l6n8sr21dtegnUazJZ5iJ2RmnEvooQx85z1hEPyuwV83lfv07164lmVf9k18= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DSbnLXAt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DSbnLXAt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86591C4CEF0; Sun, 7 Sep 2025 22:26:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757283984; bh=iTdczuKyxSrJYzwFcLxO9GNAlg2euIKIYd6uKrGA2X0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DSbnLXAtuXZQo9E+jX/EQLgmN8Ij47hKuVaxjSUyLE8RsPz9PY1isryo5T8hFnE/W UQzSWm20nJ1Cq0tn5DMxipPqidkuD0rTkPztswIHFRKB18TLQFPantT3WB0pm9TGCa 9y1zI0zGdvFt8PqTtouhB7c/gkRrvq6SJ8yGURh2GVjrPNLk7Qzeg/vrtB48dJ2Y8+ xBAygrYzRx7Y5YO38UbnMqp22+6XPmNNtHqx9Mqm8iQp/Ln8q7bIIHRw7UtIf/zGwR w6rvFc3LPIw73OhkxZ66w2EM+jG405lHcAGX5/nq3Mq/tgSMIe1Q1bahL2kc8eFHkv LEn6+qHQLyleg== From: Sasha Levin To: stable@vger.kernel.org Cc: David Hildenbrand , Alistair Popple , Alex Shi , Danilo Krummrich , Dave Airlie , Jann Horn , Jason Gunthorpe , Jerome Glisse , John Hubbard , Jonathan Corbet , Karol Herbst , Liam Howlett , Lorenzo Stoakes , Lyude , "Masami Hiramatsu (Google)" , Oleg Nesterov , Pasha Tatashin , Peter Xu , "Peter Zijlstra (Intel)" , SeongJae Park , Simona Vetter , Vlastimil Babka , Yanteng Si , Barry Song , Andrew Morton , Sasha Levin Subject: [PATCH 5.15.y] mm/rmap: reject hugetlb folios in folio_make_device_exclusive() Date: Sun, 7 Sep 2025 18:26:20 -0400 Message-ID: <20250907222620.932696-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025041752-tightwad-catwalk-8586@gregkh> References: <2025041752-tightwad-catwalk-8586@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: David Hildenbrand [ Upstream commit bc3fe6805cf09a25a086573a17d40e525208c5d8 ] Even though FOLL_SPLIT_PMD on hugetlb now always fails with -EOPNOTSUPP, let's add a safety net in case FOLL_SPLIT_PMD usage would ever be reworked. In particular, before commit 9cb28da54643 ("mm/gup: handle hugetlb in the generic follow_page_mask code"), GUP(FOLL_SPLIT_PMD) would just have returned a page. In particular, hugetlb folios that are not PMD-sized would never have been prone to FOLL_SPLIT_PMD. hugetlb folios can be anonymous, and page_make_device_exclusive_one() is not really prepared for handling them at all. So let's spell that out. Link: https://lkml.kernel.org/r/20250210193801.781278-3-david@redhat.com Fixes: b756a3b5e7ea ("mm: device exclusive memory access") Signed-off-by: David Hildenbrand Reviewed-by: Alistair Popple Tested-by: Alistair Popple Cc: Alex Shi Cc: Danilo Krummrich Cc: Dave Airlie Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Jonathan Corbet Cc: Karol Herbst Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Lyude Cc: "Masami Hiramatsu (Google)" Cc: Oleg Nesterov Cc: Pasha Tatashin Cc: Peter Xu Cc: Peter Zijlstra (Intel) Cc: SeongJae Park Cc: Simona Vetter Cc: Vlastimil Babka Cc: Yanteng Si Cc: Barry Song Cc: Signed-off-by: Andrew Morton [ folio_test_hugetlb() => PageHuge() ] Signed-off-by: Sasha Levin --- mm/rmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/rmap.c b/mm/rmap.c index 330b361a460ea..cb133bd49e029 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2184,7 +2184,7 @@ static bool page_make_device_exclusive(struct page *page, struct mm_struct *mm, * issues. Also tail pages shouldn't be passed to rmap_walk so skip * those. */ - if (!PageAnon(page) || PageTail(page)) + if (!PageAnon(page) || PageTail(page) || PageHuge(page)) return false; rmap_walk(page, &rwc); -- 2.51.0