From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CA32606A31A for ; Tue, 27 Oct 2026 00:12:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=S7GDWLGg; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=PzMJW9Xa DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=RUfo2XMc3KT6Vu8yQ39DSBh+/d0W96OJd5u+ONpJt6Q=; b=S7GDWLGgYXCYZXx+ywP8GcJ5NV 7gPlbtFh4ggqykA/DwSMj7STSj0e/Zwdj9IQUZyEbyZuAyQCu6rCsA76hW1C1W3ynNn4Dwy4u/EbA 768X8DUKFMubZ3oaUjynAxJ1g+vQv4TPGpHeuBK4Z8ckF/yYn3WG1D0a4afmsSyZ8h02bimNR5Mid LjKuVLy9FbVT5fij3YekKYWZMynMT/dQMrVRakUKQDN0r/n/pSpdbPMaO6FDoTJKuKWYjKQK2QXxW VnIgvoCdpUgZSivFXr5EjOqiN3iS4uGr/BFFy59p641n/WrRaqB2D7U32rIbR2Gzf0Spe2z2+KWw/ LXBbDsVQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUnz-00000003V0b-11NT; Tue, 27 Oct 2026 00:12:43 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUnx-00000003Uyl-1lkm for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:12:41 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 21E7243652; Tue, 27 Oct 2026 00:12:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 936071F01829; Tue, 27 Oct 2026 00:12:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793059961; bh=RUfo2XMc3KT6Vu8yQ39DSBh+/d0W96OJd5u+ONpJt6Q=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=PzMJW9XaHh9RBYXgywKmm2BurE+Df1pKrVr/6kxrArAz/bG00VQLBikM+fIBhD88K fW1mD+6KDITN3OgImzCNG0ABW2qNKPR7eUz6WQNuDoCqfTlI9dfRalrS1Y0cejkED+ d9fPTm+Ep1W0La+aBwIKCQxB9TGX4uvIl3fcUEB46CCG0kT2lQ0+fKXRnjyxNAxyEV yg250LsgVgi7vxV+xCxTdOZVgsVs863APZviVW6Z4J/DtzmDFtRAQqrvji5detEiFE tiNkv+8Ly1aj0HhPiu3JuRVkPDQZwdvRiXp0GQwFOWGGJg9X3GeNN5u3tzh+hyvpq+ 1hFwtDu0WzCxw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 12/46] mm/huge_memory: fix livelock on device private folio To: =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Andrew Morton" , "Johannes Weiner" , "Michal Hocko" , "Qi Zheng" , "Shakeel Butt" , "Lorenzo Stoakes" , "Kairui Song" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Baoquan He" , "Baolin Wang" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , =?utf-8?b?TWF0dGhldyBXaWxjb3ggKE9yYWNsZSk=?= , "Jan Kara" , "Zi Yan" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" Cc: kexec@lists.infradead.org, "Josef Bacik" In-Reply-To: <20261027-fixes_core-v1-12-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-12-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:12:38 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > From: Josef Bacik >=20 > If do_huge_pmd_device_private() cannot lock the folio, it simply returns > to try again on the next fault. >=20 > Just like we did in commit b570f37a2ce4 ("mm: Fix a hmm_range_fault() > livelock / starvation problem"), let's wait for the softleaf entry, > which will drop the PTL and wait until the folio was unlocked. This is > precisely what we do in do_swap_page() with device-private folios. This > avoids possibly livelocking. >=20 > Update softleaf_entry_wait_on_locked() documentation to clarify that > device-private entries wait until the folio is unlocked. >=20 > There seems to be no compelling reason to backport this to stable > kernels unless we actually see problems there. >=20 > Fix generated by an LLM and sent by Josef Bacik in private. >=20 > Fixes: 4964099163d0 ("mm/memory/fault: add THP fault handling for zone de= vice private pages") > Signed-off-by: Josef Bacik > [ david: simplify patch description, fixup softleaf_entry_wait_on_locked = description] > Signed-off-by: David Hildenbrand (Arm) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261027-fixes_core= -v1-0-6f74bec9a5bb@kernel.org?part=3D12