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 2834FC54EAA for ; Mon, 30 Jan 2023 14:00:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236867AbjA3OAK (ORCPT ); Mon, 30 Jan 2023 09:00:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236820AbjA3OAD (ORCPT ); Mon, 30 Jan 2023 09:00:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FCAD2C64C for ; Mon, 30 Jan 2023 05:59:45 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 1EB0661049 for ; Mon, 30 Jan 2023 13:59:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F978C433EF; Mon, 30 Jan 2023 13:59:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087184; bh=fWKNo9YVWCEv3yEo+ZJpJE/0kVWmKsWjQOfVM5cqo9I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vfgdX3heW8sXJIGwM08/EHaJh276hm6FBynPFECXBcSPyPVlYEqiaT7PInOMzPbxc PZUpGTyBtelFdQzU2XYIHUbB3bm91thQQAgSHjR0+b4AtGGb9nZhRXkj2GwMdnGi/S 06TMmaguv5vV5WFs9i4G9RWiA477MNGGIYbl5a8k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Linux Kernel Functional Testing , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 124/313] net: sched: gred: prevent races when adding offloads to stats Date: Mon, 30 Jan 2023 14:49:19 +0100 Message-Id: <20230130134342.418986216@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134336.532886729@linuxfoundation.org> References: <20230130134336.532886729@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jakub Kicinski [ Upstream commit 339346d49ae0859fe19b860998867861d37f1a76 ] Naresh reports seeing a warning that gred is calling u64_stats_update_begin() with preemption enabled. Arnd points out it's coming from _bstats_update(). We should be holding the qdisc lock when writing to stats, they are also updated from the datapath. Reported-by: Linux Kernel Functional Testing Link: https://lore.kernel.org/all/CA+G9fYsTr9_r893+62u6UGD3dVaCE-kN9C-Apmb2m=hxjc1Cqg@mail.gmail.com/ Fixes: e49efd5288bd ("net: sched: gred: support reporting stats from offloads") Link: https://lore.kernel.org/r/20230113044137.1383067-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_gred.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c index a661b062cca8..872d127c9db4 100644 --- a/net/sched/sch_gred.c +++ b/net/sched/sch_gred.c @@ -377,6 +377,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch) /* Even if driver returns failure adjust the stats - in case offload * ended but driver still wants to adjust the values. */ + sch_tree_lock(sch); for (i = 0; i < MAX_DPs; i++) { if (!table->tab[i]) continue; @@ -393,6 +394,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch) sch->qstats.overlimits += hw_stats->stats.qstats[i].overlimits; } _bstats_update(&sch->bstats, bytes, packets); + sch_tree_unlock(sch); kfree(hw_stats); return ret; -- 2.39.0