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 78704C433EF for ; Mon, 14 Feb 2022 10:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348373AbiBNKhw (ORCPT ); Mon, 14 Feb 2022 05:37:52 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:43770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348339AbiBNKes (ORCPT ); Mon, 14 Feb 2022 05:34:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C551115F; Mon, 14 Feb 2022 02:01:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AFADEB80DFE; Mon, 14 Feb 2022 10:01:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6140C340F0; Mon, 14 Feb 2022 10:01:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644832899; bh=73+Jfh2LwBaG5LGIUyw6QX/yEA7vXUv691IUNXbaKZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V5haO/ByeFs6Jl1biw1UKZrLiFjvb4twcYZ59dxp1KxFP9tRPMvXYMkWg5/ypZAx0 JNg1bRyhlVe5MICJU+NFnPHIlfwlJkONJqK1U7LpRgaa6R1jl2jcp2aMLh+jkjPduo wr6SXy20pNX7Zq2HH2CYBdPXqF+xFXHNxwtS5soA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Colin Foster , Vladimir Oltean , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.16 160/203] net: mscc: ocelot: fix mutex lock error during ethtool stats read Date: Mon, 14 Feb 2022 10:26:44 +0100 Message-Id: <20220214092515.675063913@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220214092510.221474733@linuxfoundation.org> References: <20220214092510.221474733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Foster [ Upstream commit 7fbf6795d127a3b1bb39b0e42579904cf6db1624 ] An ongoing workqueue populates the stats buffer. At the same time, a user might query the statistics. While writing to the buffer is mutex-locked, reading from the buffer wasn't. This could lead to buggy reads by ethtool. This patch fixes the former blamed commit, but the bug was introduced in the latter. Signed-off-by: Colin Foster Fixes: 1e1caa9735f90 ("ocelot: Clean up stats update deferred work") Fixes: a556c76adc052 ("net: mscc: Add initial Ocelot switch support") Reported-by: Vladimir Oltean Reviewed-by: Vladimir Oltean Link: https://lore.kernel.org/all/20220210150451.416845-2-colin.foster@in-advantage.com/ Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/mscc/ocelot.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c index ac5849436d021..02edd383dea22 100644 --- a/drivers/net/ethernet/mscc/ocelot.c +++ b/drivers/net/ethernet/mscc/ocelot.c @@ -1609,12 +1609,11 @@ void ocelot_get_strings(struct ocelot *ocelot, int port, u32 sset, u8 *data) } EXPORT_SYMBOL(ocelot_get_strings); +/* Caller must hold &ocelot->stats_lock */ static void ocelot_update_stats(struct ocelot *ocelot) { int i, j; - mutex_lock(&ocelot->stats_lock); - for (i = 0; i < ocelot->num_phys_ports; i++) { /* Configure the port to read the stats from */ ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(i), SYS_STAT_CFG); @@ -1633,8 +1632,6 @@ static void ocelot_update_stats(struct ocelot *ocelot) ~(u64)U32_MAX) + val; } } - - mutex_unlock(&ocelot->stats_lock); } static void ocelot_check_stats_work(struct work_struct *work) @@ -1643,7 +1640,9 @@ static void ocelot_check_stats_work(struct work_struct *work) struct ocelot *ocelot = container_of(del_work, struct ocelot, stats_work); + mutex_lock(&ocelot->stats_lock); ocelot_update_stats(ocelot); + mutex_unlock(&ocelot->stats_lock); queue_delayed_work(ocelot->stats_queue, &ocelot->stats_work, OCELOT_STATS_CHECK_DELAY); @@ -1653,12 +1652,16 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data) { int i; + mutex_lock(&ocelot->stats_lock); + /* check and update now */ ocelot_update_stats(ocelot); /* Copy all counters */ for (i = 0; i < ocelot->num_stats; i++) *data++ = ocelot->stats[port * ocelot->num_stats + i]; + + mutex_unlock(&ocelot->stats_lock); } EXPORT_SYMBOL(ocelot_get_ethtool_stats); -- 2.34.1