From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794273802; b=vERBjXsHdBLvjgYGijKEI0nHBLub0lV4gHMtvf3B52OuPOZo3fEKEbDJmKI20DUfZqPi M170lo1BVzPMrWddWBYfmTeyn3Dsyfga4AxuoOeSwCdzCWY210SLVpmuQQgBsKRaEH/e9 p+YpN57WyKHq5R8GsOLSJ4LMkC+0tCjmcgJiot5s189P92K8loqPQN4FAt6/t6wf07ZVb FUY1vHAhGuMIG0IPw9oRlsCWy+hj115J9lLHkSbGTsyGF7SnC63jiVREcvHlGnaME2nKn T6A/x0dAu8p4K92mW4qUNIKmjoTGgdt06jBxSJJecGXyYgz5VQP5u4XQ4HpJCuwEarg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273802; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=KhIy0nP6WsKWDR32sknF6E2LCNXcQiyf8aY0nLYO8Cs=; b=s1N890OqTwsDEY10r5UAQXYtzQ8ldv/znRkeWSjucM7yFr7u6s6mdWBM25i4zIBnJxDc WkMajemfSQek315fcFK8AAODKvaLkE0kM3bzBCpyLPPyhQ1VQmK5ClzDADIpqkfbqh5e1 bQQilJoieleEN3vZh0L29NpseUkNaj1bgRvSnGJbzExUWDFSZJS/3Z2x66OLg4SPmK/ag ZZAAqdUKdxajlkXFPTlAuisfums5YngsfajWd08t1aptdHFYk014QQwpY6iONWF2S4g2v mvAvSFWbeGEog1a/6oJmRMNcqR1Ovee65AlZb9yFf6Rv1WZXMO4x/p/QZgfqN/8FKOQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="aZr8yeD/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9978C6071843 for ; Tue, 10 Nov 2026 01:23:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=aZr8yeD/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F0BA1F0089F; Tue, 10 Nov 2026 01:23:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273802; bh=KhIy0nP6WsKWDR32sknF6E2LCNXcQiyf8aY0nLYO8Cs=; h=From:To:Cc:Subject:Date; b=aZr8yeD/n5z2ahQoIDnwCLo943TLkUAPQGNih9c1Mf5vF7HHKvZ1rJZhPdubBMkMj 5wIUDWeRNR/Q6PTK7TQmKgtty7EgmcHICBaRcDxhMBpQ8BhyqHxbbsUNDJoeDE5kXY T6kksnitOXBaZu+vTrZOBndYtM+15zckk94tbj/hw1QIwpxU8VC3CoEMmmJ/3v4f+L mI+LqX6qD1kZhOTimhZjrJJ5/5MVZTBQpe9xG8dCN6LTlu58hKXqK9tI8qE/Hwrxak eh/q3t9HrAVJlP+6r+s3rk1NGp3VzkzFbXQ3cf2/nHHBnEihxXX3tJ7SRfAnq6K6Cj 2L6bYk7BUQlSA== From: Sasha Levin To: mason@kernel.org, gourry@gourry.net, usama.anjum@arm.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, david@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mm/huge_memory: fix truncate racing with PMD zapping" failed to apply to 5.15-stable tree Date: Mon, 9 Nov 2026 20:23:20 -0500 Message-ID: <20261109202320-failed-5.15-e6a07d29b0a6@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-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 . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e6a07d29b0a60f3a4cfe77fe34eeb4b3fb38d6c4 # git commit -s git send-email --to '' --in-reply-to '20261109202320-failed-5.15-e6a07d29b0a6@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From e6a07d29b0a60f3a4cfe77fe34eeb4b3fb38d6c4 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Sat, 31 Oct 2026 10:39:42 +0100 Subject: [PATCH] mm/huge_memory: fix truncate racing with PMD zapping zap_huge_pmd_folio() removes the rmap before calling folio_mark_dirty(). If this was the last mapping, truncation can skip unmapping the folio and proceed without waiting for the PMD lock, racing with dirtying. ifs_set_range_dirty() can oops if MADV_DONTNEED races with ftruncate() on XFS, when we get the folio set dirty after it was found to not be mapped anymore. Move folio_mark_dirty() and folio_mark_accessed() before rmap removal, matching the PTE zap path. This keeps the folio mapped while updating its state, so truncation must wait for the page table lock. Fix generated by an LLM and sent by Chris Mason in private. Fixes: fe6cf984939d ("mm/huge_memory: transfer the pmd dirty bit to the folio on zap") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify comment and description ] Reviewed-by: Gregory Price (Meta) Tested-by: Muhammad Usama Anjum Link: https://patch.msgid.link/20261031-fixes_core-v3-13-d6437171ecc3@kernel.org Reviewed-by: Zi Yan Reviewed-by: Baolin Wang Signed-off-by: David Hildenbrand (Arm) --- mm/huge_memory.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 283c4bc8b927c..ce52962db16b9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2495,10 +2495,6 @@ static void zap_huge_pmd_folio(struct mm_struct *mm, struct vm_area_struct *vma, { const bool is_device_private = folio_is_device_private(folio); - /* Present and device private folios are rmappable. */ - if (is_present || is_device_private) - folio_remove_rmap_pmd(folio, &folio->page, vma); - if (folio_test_anon(folio)) { add_mm_counter(mm, MM_ANONPAGES, -HPAGE_PMD_NR); } else { @@ -2512,6 +2508,13 @@ static void zap_huge_pmd_folio(struct mm_struct *mm, struct vm_area_struct *vma, folio_mark_accessed(folio); } + /* + * Present and device private folios are rmappable. Remove the + * rmap after transferring young+dirty to the folio. + */ + if (is_present || is_device_private) + folio_remove_rmap_pmd(folio, &folio->page, vma); + /* Device private folios are pinned. */ if (is_device_private) folio_put(folio); -- 2.53.0