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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A2E1C43381 for ; Wed, 27 Mar 2019 19:12:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1782206C0 for ; Wed, 27 Mar 2019 19:12:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553713961; bh=RwDSvDrJpi9ErNnsHMtIec3eG0IaEYGWG1YrxeSsccQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DHvW9yKUCiA8hOLTETlVFbF9Q7JTjT+XFu07E0Bc8sk5HH5AbLcX3DYGdBJtVNylO tH7fVojJC37K+dx70SaXfABau6t12QS8w8zuU95JW9zmAkCUO5c5lXFqoFNy5R6Xpa gdgbGqJ5j+4qN2T/UrpRs5PlusaGyLWq0++MzZSc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388983AbfC0TMe (ORCPT ); Wed, 27 Mar 2019 15:12:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:52386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388334AbfC0SKY (ORCPT ); Wed, 27 Mar 2019 14:10:24 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D724B2147C; Wed, 27 Mar 2019 18:10:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710223; bh=RwDSvDrJpi9ErNnsHMtIec3eG0IaEYGWG1YrxeSsccQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zQp1jDS7enOstCIGTm+Bq0LrVAjOT9xRXGy0BI0+pbjAlt9NQ6ZPDuS3UIpJpjFUI pVYj2aj2Cfa2Gfa6nmHWA0JdtKkmssht5j7Py9XO0j8ojVBo20ggobz67KbRoXwrtq eyshN7b4iTBCASCBKZi3t4VQC23FII19F+tmBfIc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Jens Axboe , Sasha Levin , linux-bcache@vger.kernel.org Subject: [PATCH AUTOSEL 5.0 262/262] bcache: fix potential div-zero error of writeback_rate_p_term_inverse Date: Wed, 27 Mar 2019 14:01:57 -0400 Message-Id: <20190327180158.10245-262-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327180158.10245-1-sashal@kernel.org> References: <20190327180158.10245-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Coly Li [ Upstream commit 5b5fd3c94eef69dcfaa8648198e54c92e5687d6d ] Current code already uses d_strtoul_nonzero() to convert input string to an unsigned integer, to make sure writeback_rate_p_term_inverse won't be zero value. But overflow may happen when converting input string to an unsigned integer value by d_strtoul_nonzero(), then dc->writeback_rate_p_term_inverse can still be set to 0 even if the sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1). If dc->writeback_rate_p_term_inverse is set to 0, it might cause a dev-zero error in following code from __update_writeback_rate(), int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and limit the value range in [1, UINT_MAX]. Then the unsigned integer overflow and dev-zero error can be avoided. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/md/bcache/sysfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 28e0d5a5e25b..e5daf91310f6 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -290,7 +290,9 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_rate_i_term_inverse, dc->writeback_rate_i_term_inverse, 1, UINT_MAX); - d_strtoul_nonzero(writeback_rate_p_term_inverse); + sysfs_strtoul_clamp(writeback_rate_p_term_inverse, + dc->writeback_rate_p_term_inverse, + 1, UINT_MAX); d_strtoul_nonzero(writeback_rate_minimum); sysfs_strtoul_clamp(io_error_limit, dc->error_limit, 0, INT_MAX); -- 2.19.1