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=1794273733; b=L6xT0BpdtLkR6/pSPdL3xVHCjMTDj9DKrxyz/iiuAQgyTV2TevylYi5L/m6sjoo92yr0 r5Yli4jy3VKBqZ95f1NRnQxfuYJEFkMAoXRuXTWt3Br45i5qvgkrI6+mIEJSm0g9GCOJM qZrB7sYQyNBGSCnKwnEA2f3xRDIYQTbCiT2NnB9UWv2tr3zx2nDBTKiYi/4m8si2Rs+l2 m1dEKOUwSnCqgagH2/8qI2pJ5YMov7OoXl057dWSVPXdO8z/fTBzBwTFETg9K0FhFCZjb 0suxghO/wTymVeggkOb2JhvvHxUt233E2mYiT1i+4UZeXk03ZBFAVNbZE+MfXyDec3A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273733; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=/iw81Ukno+/GFpNxlOFNQ6IEIPGlD9QMDmHYLD8gZC8=; b=4gLbRT7kVjJFYzhpTF6skZnaMANrF4+Pdwwzl8jqHoQ4/2gTcGoDmJ4TtvUeE+VT+lmS +KKEf6qy0XvM/MACMIhSzkRRThqbZuliZkDi8AI8lbN+e5T+HqU1KEVf89F5YDOKkcJYQ /QPhjOmjntTcRrVb8ISXSuwbPbuTs4WfIAb3w21F5nj8uT08I3MFHYLddqwOFj8XbS7jR yPbg4hevtJG/ZD1U4OZ8hPgeQisstlrURNate7Wbnfnj7g6uHVa8ji3AHXkLR16sdc6Bh Ttq2hn20nCszhY3gapg4K3zJHZRUXTd3mdzwDKbecxK+sRzUzaJRxPx/l0v5cd9/9Mw== 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="NuFkjV/w"; 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 5C33A60A5BD4 for ; Tue, 10 Nov 2026 01:22:13 +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=NuFkjV/w Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FBE31F008A2; Tue, 10 Nov 2026 01:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273733; bh=/iw81Ukno+/GFpNxlOFNQ6IEIPGlD9QMDmHYLD8gZC8=; h=From:To:Cc:Subject:Date; b=NuFkjV/w/SeSWOxt5tVhKPQ7SEQk1Dggc//AVEHya/yFu01Jnm8XHAKDwCn7pdxk8 qCJ51h/cYivAzfVwHYA8pxE4uhDC/IOxy+bAOFG19L7oVNEBh/V/8KBTIZ3h4mEQVG fZt/fjKlH5RGUcik9d2B440+SMcNbJ5amtrutpqdshAACS7Uxfxj4aF6skbhUbIhcB gs8pyzOyHt5eEaI+2XGDQSmRXkiMAdFeJhPcR+b+a7EJchmhnLj8PIL6MwsuqQWVw4 6vVlIbbec/yaCCOvldQtofGvut8nivWEST/E9blixdbkwEUU/Z/e4R0Grep1edea3f ni5X1grjFb/0A== From: Sasha Levin To: samarth.colleges@gmail.com, akpm@linux-foundation.org, lance.yang@linux.dev, david@kernel.org, xu.xin@linux.dev, chengming.zhou@linux.dev, peterx@redhat.com, kas@kernel.org, rppt@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mm/ksm: keep soft-dirty when merging a page" failed to apply to 5.15-stable tree Date: Mon, 9 Nov 2026 20:22:10 -0500 Message-ID: <20261109202210-failed-5.15-2efc6332f18b@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 2efc6332f18bfd848f74f3d5ba45b31450601faa # git commit -s git send-email --to '' --in-reply-to '20261109202210-failed-5.15-2efc6332f18b@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 2efc6332f18bfd848f74f3d5ba45b31450601faa Mon Sep 17 00:00:00 2001 From: Samarth Narang Date: Wed, 21 Oct 2026 11:21:57 -0700 Subject: [PATCH] mm/ksm: keep soft-dirty when merging a page replace_page() maps the KSM page with a PTE built from scratch, so the soft-dirty bit of the PTE it replaces is lost. A page written since "clear_refs 4" then no longer shows as soft-dirty once it is merged, and a soft-dirty based dumper treats it as unchanged. Copy the soft-dirty bit from the original PTE to the new PTE. Link: https://lore.kernel.org/20261021182157.1873726-1-samarth.colleges@gmail.com Fixes: 0f8975ec4db2 ("mm: soft-dirty bits for user memory changes tracking") Signed-off-by: Samarth Narang Signed-off-by: Andrew Morton Reviewed-by: Lance Yang Acked-by: David Hildenbrand (Arm) Assisted-by: LLM Cc: Xu Xin Cc: Chengming Zhou Cc: Peter Xu Cc: Kiryl Shutsemau Cc: Mike Rapoport Cc: --- mm/ksm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/ksm.c b/mm/ksm.c index dbfb8f98b1892..910a1307ac9f3 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1463,6 +1463,10 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, dec_mm_counter(mm, MM_ANONPAGES); } + /* Preserve soft-dirty when replacing the page. */ + if (pte_soft_dirty(orig_pte)) + newpte = pte_mksoft_dirty(newpte); + flush_cache_page(vma, addr, pte_pfn(ptep_get(ptep))); /* * No need to notify as we are replacing a read only page with another -- 2.53.0