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 61DAC381D6; Fri, 24 Nov 2023 18:14:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="WTWEJrbk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D74B6C433C7; Fri, 24 Nov 2023 18:14:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700849683; bh=UKvrc9vr/g/5BBQukXl9uTsncor+kai8cIrvP/UOF48=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WTWEJrbkCLEpVpbY/2E4U+PMFt92hO1LYwNVmqRdjJizVrOJmw5t+v3+Kjbb3p1TX YJLk31zag16hR6G8YPcuJiHg+Lkz/QmEg84dALia3CU8ZhPpL/5sp9PxFsOp+NFMi3 eq/80ahcFKUJIkpjcyb/Sih/xni2oha04VU2liDM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, SeongJae Park , Jakub Acs , Andrew Morton Subject: [PATCH 6.6 279/530] mm/damon/lru_sort: avoid divide-by-zero in hot threshold calculation Date: Fri, 24 Nov 2023 17:47:25 +0000 Message-ID: <20231124172036.540446494@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124172028.107505484@linuxfoundation.org> References: <20231124172028.107505484@linuxfoundation.org> User-Agent: quilt/0.67 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: SeongJae Park commit 44063f125af4bb4efd1d500d8091fa33a98af325 upstream. 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 Reported-by: Jakub Acs Cc: [6.0+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/damon/lru_sort.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/mm/damon/lru_sort.c +++ b/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)