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 9D5DBC433FE for ; Mon, 7 Mar 2022 09:21:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236613AbiCGJWh (ORCPT ); Mon, 7 Mar 2022 04:22:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236596AbiCGJWR (ORCPT ); Mon, 7 Mar 2022 04:22:17 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9520A6662A; Mon, 7 Mar 2022 01:20:31 -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 45507B81054; Mon, 7 Mar 2022 09:20:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 730FBC340E9; Mon, 7 Mar 2022 09:20:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646644828; bh=tohyZRhddFOBEy3gO5lm9g2AbMMXdntkNRSQfG7NnjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sdIEpxWQvbf0i5E56MqkCPIx9lVSZYExpxQ/S9oVeLjnnX6bgEESLPOO9jCzzb/rk QHVsTBqGzj7ZsLbypMPYCFPkREkNYOLNLLoptw1Qk5ynSYLVtuw814JFBMjyEpuvRs rChmU8V3VyQcN7p6hyaDt4R3Ik+WNveV5+/ptn5U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Vladimir Oltean , Jakub Kicinski Subject: [PATCH 4.9 32/32] net: dcb: disable softirqs in dcbnl_flush_dev() Date: Mon, 7 Mar 2022 10:18:58 +0100 Message-Id: <20220307091635.351396827@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220307091634.434478485@linuxfoundation.org> References: <20220307091634.434478485@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: Vladimir Oltean commit 10b6bb62ae1a49ee818fc479cf57b8900176773e upstream. Ido Schimmel points out that since commit 52cff74eef5d ("dcbnl : Disable software interrupts before taking dcb_lock"), the DCB API can be called by drivers from softirq context. One such in-tree example is the chelsio cxgb4 driver: dcb_rpl -> cxgb4_dcb_handle_fw_update -> dcb_ieee_setapp If the firmware for this driver happened to send an event which resulted in a call to dcb_ieee_setapp() at the exact same time as another DCB-enabled interface was unregistering on the same CPU, the softirq would deadlock, because the interrupted process was already holding the dcb_lock in dcbnl_flush_dev(). Fix this unlikely event by using spin_lock_bh() in dcbnl_flush_dev() as in the rest of the dcbnl code. Fixes: 91b0383fef06 ("net: dcb: flush lingering app table entries for unregistered devices") Reported-by: Ido Schimmel Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20220302193939.1368823-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/dcb/dcbnl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -1942,7 +1942,7 @@ static void dcbnl_flush_dev(struct net_d { struct dcb_app_type *itr, *tmp; - spin_lock(&dcb_lock); + spin_lock_bh(&dcb_lock); list_for_each_entry_safe(itr, tmp, &dcb_app_list, list) { if (itr->ifindex == dev->ifindex) { @@ -1951,7 +1951,7 @@ static void dcbnl_flush_dev(struct net_d } } - spin_unlock(&dcb_lock); + spin_unlock_bh(&dcb_lock); } static int dcbnl_netdevice_event(struct notifier_block *nb,