From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73098C19F5C for ; Fri, 20 Oct 2023 17:18:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbjJTRS6 (ORCPT ); Fri, 20 Oct 2023 13:18:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229875AbjJTRSz (ORCPT ); Fri, 20 Oct 2023 13:18:55 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 788BD13E; Fri, 20 Oct 2023 10:18:53 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 127E5C433C8; Fri, 20 Oct 2023 17:18:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1697822333; bh=9OYVShPRSQVVFBfdVQCEJSwJVreEwqTHLOyJV55tUO4=; h=Date:To:From:Subject:From; b=E1RMwPTlMhdqWeSE6SzcXWG6WEtKnZpEqwmcGwXf/QJAxQNfskp0v/z51L9znMghI R9SdzW7LDWRtv7wpD6z4tuxroGrst0KH6/sou3a69gZ2oLcbNOaGR9FYnA1kbPD3bC HXhcV9Bnl3F1nycy0Uj+QwL2CC+Wbq1uUuHRn6Gs= Date: Fri, 20 Oct 2023 10:18:52 -0700 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, sj@kernel.org, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch added to mm-hotfixes-unstable branch Message-Id: <20231020171853.127E5C433C8@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/damon/lru_sort: avoid divide-by-zero in hot threshold calculation has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: SeongJae Park Subject: mm/damon/lru_sort: avoid divide-by-zero in hot threshold calculation Date: Thu, 19 Oct 2023 19:49:23 +0000 When calculating the hotness threshold for lru_prio scheme of DAMON_LRU_SORT, the module divides some values by the maximum nr_accesses. However, due to the type of the related variables, simple division-based calculation of the divisor can return zero. As a result, divide-by-zero is possible. Fix it by using damon_max_nr_accesses(), which handles the case. Link: https://lkml.kernel.org/r/20231019194924.100347-5-sj@kernel.org Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting") Signed-off-by: SeongJae Park Cc: [6.0+] Signed-off-by: Andrew Morton --- mm/damon/lru_sort.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/mm/damon/lru_sort.c~mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation +++ a/mm/damon/lru_sort.c @@ -193,9 +193,7 @@ static int damon_lru_sort_apply_paramete if (err) return err; - /* aggr_interval / sample_interval is the maximum nr_accesses */ - hot_thres = damon_lru_sort_mon_attrs.aggr_interval / - damon_lru_sort_mon_attrs.sample_interval * + hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) * hot_thres_access_freq / 1000; scheme = damon_lru_sort_new_hot_scheme(hot_thres); if (!scheme) _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-implement-a-function-for-max-nr_accesses-safe-calculation.patch mm-damon-core-avoid-divide-by-zero-during-monitoring-results-update.patch mm-damon-ops-common-avoid-divide-by-zero-during-region-hotness-calculation.patch mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch