From nobody Sun Nov 24 11:58:44 2024 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 EDA16190676; Wed, 6 Nov 2024 02:09:52 +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=1730858993; cv=none; b=BWbtXYrPH/DdG0AkO3q5Es1GKMCEX+yJCgJwaQacbdHh0hHCezvEsUxRFt4XHQZxgAV0I7TJfMvNJP/XDAK7mmCI0PF9XNkHBO2D+JEpF6PmItoFljfJjEqMo/4sI5FMJR1ndnOXAgCVeGxZjvjfsVeEmOPRbt3Sw68UmO5G230= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730858993; c=relaxed/simple; bh=kV2fAIghnGPusjLtFBOK8Mq7voh7UMy0XjPiuOjfqxA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=HrzDKt+jGl+6gBE8T90eTZsWkfnnzMP0Kz20t1qGJWuW/+PIXFNOroVdgZw2Ec8ZtcQJP5ErpGj/7cJfGT9gJ4MdGlMDQdSsDidygd8k4tIdHElReO450PfX3LkqgZPaQJzdrHJZS5aeLvKnaFp9c00ecd+gcLBJM3Tw2DKozlc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=t1sX9AKJ; 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="t1sX9AKJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 009BBC4CECF; Wed, 6 Nov 2024 02:09:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730858992; bh=kV2fAIghnGPusjLtFBOK8Mq7voh7UMy0XjPiuOjfqxA=; h=From:To:Cc:Subject:Date:From; b=t1sX9AKJaAohFfzzOys5q67cFM4mKBUnw1428X65MqzJ2doIRj8H9bpL4lbQYIfyd 0U2k/LGt1UuwWJ0y5g6yf0cMKUj2gfi8nFrYzpEhMh59tvh/sZWXAXRReYZqrQc8PX haGeMymGgN9TijsxGN8tYNYlkHYpgC+rE2JDtmzJ/i2fxrQIudC6ndg9uXu6I5CMwf iUNmsQ6jIF+ze6/G1mbM4qFVCJWUi+/zMdKfDjtaPuAPc8Ri4wp8owatiKheT2nm96 ecHuliMwsRaboMPN3CCSsidXKesWQG10CkBXmcry+0APlUc+id+Q3nwsNY1uei37BR zOFkhazq9+NIA== From: Sasha Levin To: stable@vger.kernel.org, yuzhao@google.com Cc: Matthew Wilcox , Muchun Song , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: FAILED: Patch "mm: allow set/clear page_type again" failed to apply to v6.6-stable tree Date: Tue, 5 Nov 2024 21:09:48 -0500 Message-ID: <20241106020949.173366-1-sashal@kernel.org> 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 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The patch below does not apply to the v6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ From 9d08ec41a0645283d79a2e642205d488feaceacf Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Sat, 19 Oct 2024 22:22:12 -0600 Subject: [PATCH] mm: allow set/clear page_type again Some page flags (page->flags) were converted to page types (page->page_types). A recent example is PG_hugetlb. From the exclusive writer's perspective, e.g., a thread doing __folio_set_hugetlb(), there is a difference between the page flag and type APIs: the former allows the same non-atomic operation to be repeated whereas the latter does not. For example, calling __folio_set_hugetlb() twice triggers VM_BUG_ON_FOLIO(), since the second call expects the type (PG_hugetlb) not to be set previously. Using add_hugetlb_folio() as an example, it calls __folio_set_hugetlb() in the following error-handling path. And when that happens, it triggers the aforementioned VM_BUG_ON_FOLIO(). if (folio_test_hugetlb(folio)) { rc =3D hugetlb_vmemmap_restore_folio(h, folio); if (rc) { spin_lock_irq(&hugetlb_lock); add_hugetlb_folio(h, folio, false); ... It is possible to make hugeTLB comply with the new requirements from the page type API. However, a straightforward fix would be to just allow the same page type to be set or cleared again inside the API, to avoid any changes to its callers. Link: https://lkml.kernel.org/r/20241020042212.296781-1-yuzhao@google.com Fixes: d99e3140a4d3 ("mm: turn folio_test_hugetlb into a PageType") Signed-off-by: Yu Zhao Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 1b3a767104878..cc839e4365c18 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -975,12 +975,16 @@ static __always_inline bool folio_test_##fname(const = struct folio *folio) \ } \ static __always_inline void __folio_set_##fname(struct folio *folio) \ { \ + if (folio_test_##fname(folio)) \ + return; \ VM_BUG_ON_FOLIO(data_race(folio->page.page_type) !=3D UINT_MAX, \ folio); \ folio->page.page_type =3D (unsigned int)PGTY_##lname << 24; \ } \ static __always_inline void __folio_clear_##fname(struct folio *folio) \ { \ + if (folio->page.page_type =3D=3D UINT_MAX) \ + return; \ VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \ folio->page.page_type =3D UINT_MAX; \ } @@ -993,11 +997,15 @@ static __always_inline int Page##uname(const struct p= age *page) \ } \ static __always_inline void __SetPage##uname(struct page *page) \ { \ + if (Page##uname(page)) \ + return; \ VM_BUG_ON_PAGE(data_race(page->page_type) !=3D UINT_MAX, page); \ page->page_type =3D (unsigned int)PGTY_##lname << 24; \ } \ static __always_inline void __ClearPage##uname(struct page *page) \ { \ + if (page->page_type =3D=3D UINT_MAX) \ + return; \ VM_BUG_ON_PAGE(!Page##uname(page), page); \ page->page_type =3D UINT_MAX; \ } --=20 2.43.0