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 2FF89234977; Mon, 10 Mar 2025 17:24:35 +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=1741627475; cv=none; b=n/PWnMDBhoxZ1FhOg0sxF/obL9PFbgu6DPyA71X9wwKhBFi2arBTGxvBUHLKtNde5yC2YCiwqWe0WtZcO2WnGsTdloUsZs5pnZh4nW+OR47jOccq6JXfr4gwXvPUIUqfqnqZvMbA6nK2Nl1rAmsyxwMm2SWhsZyOUjedaBR33y0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741627475; c=relaxed/simple; bh=P+Ojc9Nxub0WxyU3khEVmZMTx6hrvFT8AobOabCawag=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SeHjmiTXVluofTfu/HsFthYAF4p42WI6UqMq/vaf/50eZ1Ei5FCvOR8W0yijVSgOVVynzAiGnRAi+K+Xq3sdstL/yBwoxHByGbWvKNzdvJtU7LAOoLJsdykzHGW9DjhEG/+Rh6XwZyEXjxK1/TdaDtOeJdE3kFNiHkYvh9EyQ5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dtnbmyfh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dtnbmyfh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A794EC4CEE5; Mon, 10 Mar 2025 17:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741627475; bh=P+Ojc9Nxub0WxyU3khEVmZMTx6hrvFT8AobOabCawag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dtnbmyfhNVdTIei1xQMDiF+uEUoMdJFa3a8/B1cbSscyyUbBEi5ZNV4jqr1cZAHai adv/bHCqooClvfJB5sAy3TZINDs669O6iD04Ab4izYh7qHfFBt4oUD4BBwuE4tuD+I 5xGiqfKfNaCZJ9Ry8WhuBnEuh+HCDhQSTLn1apFA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ma Wupeng , David Hildenbrand , Miaohe Lin , Michal Hocko , Naoya Horiguchi , Oscar Salvador , Andrew Morton Subject: [PATCH 6.12 140/269] mm: memory-hotplug: check folio ref count first in do_migrate_range Date: Mon, 10 Mar 2025 18:04:53 +0100 Message-ID: <20250310170503.301111336@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170457.700086763@linuxfoundation.org> References: <20250310170457.700086763@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ma Wupeng commit 773b9a6aa6d38894b95088e3ed6f8a701d9f50fd upstream. If a folio has an increased reference count, folio_try_get() will acquire it, perform necessary operations, and then release it. In the case of a poisoned folio without an elevated reference count (which is unlikely for memory-failure), folio_try_get() will simply bypass it. Therefore, relocate the folio_try_get() function, responsible for checking and acquiring this reference count at first. Link: https://lkml.kernel.org/r/20250217014329.3610326-3-mawupeng1@huawei.com Signed-off-by: Ma Wupeng Acked-by: David Hildenbrand Acked-by: Miaohe Lin Cc: Michal Hocko Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/memory_hotplug.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1795,12 +1795,12 @@ static void do_migrate_range(unsigned lo if (folio_test_large(folio)) pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1; - /* - * HWPoison pages have elevated reference counts so the migration would - * fail on them. It also doesn't make any sense to migrate them in the - * first place. Still try to unmap such a page in case it is still mapped - * (keep the unmap as the catch all safety net). - */ + if (!folio_try_get(folio)) + continue; + + if (unlikely(page_folio(page) != folio)) + goto put_folio; + if (folio_test_hwpoison(folio) || (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) { if (WARN_ON(folio_test_lru(folio))) @@ -1811,14 +1811,8 @@ static void do_migrate_range(unsigned lo folio_unlock(folio); } - continue; - } - - if (!folio_try_get(folio)) - continue; - - if (unlikely(page_folio(page) != folio)) goto put_folio; + } if (!isolate_folio_to_list(folio, &source)) { if (__ratelimit(&migrate_rs)) {