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 C4418C54EED for ; Mon, 30 Jan 2023 14:13:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237214AbjA3ONL (ORCPT ); Mon, 30 Jan 2023 09:13:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237263AbjA3ONH (ORCPT ); Mon, 30 Jan 2023 09:13:07 -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 6C3B6303E7 for ; Mon, 30 Jan 2023 06:12:44 -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 0DB84B8117E for ; Mon, 30 Jan 2023 14:12:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59923C433D2; Mon, 30 Jan 2023 14:12:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087962; bh=O2ATFCr5Bp6JCp/jjo8gRPqNH4H9jidCSx/S1HljqTI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yx0OWDvihYXex4ATw07cEvs75CoEao1u+qyGTVQ5mc75Tpt1G+M0BTKfda/cmTqpq W7f5aAECL0z6FLIglS8YY3JQDTgBWHJIT801JExIUUca8wLIzbe8c3CEIA8MRcB1zu eEM82aWFeds8ZISMBW8wZcwUtIlNab6WldoBXNp8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vladimir Oltean , Alexander Duyck , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 040/204] net: enetc: avoid deadlock in enetc_tx_onestep_tstamp() Date: Mon, 30 Jan 2023 14:50:05 +0100 Message-Id: <20230130134318.074236771@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134316.327556078@linuxfoundation.org> References: <20230130134316.327556078@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: Vladimir Oltean [ Upstream commit 3c463721a73bdb57a913e0d3124677a3758886fc ] This lockdep splat says it better than I could: ================================ WARNING: inconsistent lock state 6.2.0-rc2-07010-ga9b9500ffaac-dirty #967 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. kworker/1:3/179 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff3ec4036ce098 (_xmit_ETHER#2){+.?.}-{3:3}, at: netif_freeze_queues+0x5c/0xc0 {IN-SOFTIRQ-W} state was registered at: _raw_spin_lock+0x5c/0xc0 sch_direct_xmit+0x148/0x37c __dev_queue_xmit+0x528/0x111c ip6_finish_output2+0x5ec/0xb7c ip6_finish_output+0x240/0x3f0 ip6_output+0x78/0x360 ndisc_send_skb+0x33c/0x85c ndisc_send_rs+0x54/0x12c addrconf_rs_timer+0x154/0x260 call_timer_fn+0xb8/0x3a0 __run_timers.part.0+0x214/0x26c run_timer_softirq+0x3c/0x74 __do_softirq+0x14c/0x5d8 ____do_softirq+0x10/0x20 call_on_irq_stack+0x2c/0x5c do_softirq_own_stack+0x1c/0x30 __irq_exit_rcu+0x168/0x1a0 irq_exit_rcu+0x10/0x40 el1_interrupt+0x38/0x64 irq event stamp: 7825 hardirqs last enabled at (7825): [] exit_to_kernel_mode+0x34/0x130 hardirqs last disabled at (7823): [] __do_softirq+0x550/0x5d8 softirqs last enabled at (7824): [] __do_softirq+0x46c/0x5d8 softirqs last disabled at (7811): [] ____do_softirq+0x10/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** 3 locks held by kworker/1:3/179: #0: ffff3ec400004748 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0 #1: ffff80000a0bbdc8 ((work_completion)(&priv->tx_onestep_tstamp)){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0 #2: ffff3ec4036cd438 (&dev->tx_global_lock){+.+.}-{3:3}, at: netif_tx_lock+0x1c/0x34 Workqueue: events enetc_tx_onestep_tstamp Call trace: print_usage_bug.part.0+0x208/0x22c mark_lock+0x7f0/0x8b0 __lock_acquire+0x7c4/0x1ce0 lock_acquire.part.0+0xe0/0x220 lock_acquire+0x68/0x84 _raw_spin_lock+0x5c/0xc0 netif_freeze_queues+0x5c/0xc0 netif_tx_lock+0x24/0x34 enetc_tx_onestep_tstamp+0x20/0x100 process_one_work+0x28c/0x6c0 worker_thread+0x74/0x450 kthread+0x118/0x11c but I'll say it anyway: the enetc_tx_onestep_tstamp() work item runs in process context, therefore with softirqs enabled (i.o.w., it can be interrupted by a softirq). If we hold the netif_tx_lock() when there is an interrupt, and the NET_TX softirq then gets scheduled, this will take the netif_tx_lock() a second time and deadlock the kernel. To solve this, use netif_tx_lock_bh(), which blocks softirqs from running. Fixes: 7294380c5211 ("enetc: support PTP Sync packet one-step timestamping") Signed-off-by: Vladimir Oltean Reviewed-by: Alexander Duyck Link: https://lore.kernel.org/r/20230112105440.1786799-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/freescale/enetc/enetc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c index adccb14c1644..8b7c93447770 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc.c +++ b/drivers/net/ethernet/freescale/enetc/enetc.c @@ -2000,14 +2000,14 @@ static void enetc_tx_onestep_tstamp(struct work_struct *work) priv = container_of(work, struct enetc_ndev_priv, tx_onestep_tstamp); - netif_tx_lock(priv->ndev); + netif_tx_lock_bh(priv->ndev); clear_bit_unlock(ENETC_TX_ONESTEP_TSTAMP_IN_PROGRESS, &priv->flags); skb = skb_dequeue(&priv->tx_skbs); if (skb) enetc_start_xmit(skb, priv->ndev); - netif_tx_unlock(priv->ndev); + netif_tx_unlock_bh(priv->ndev); } static void enetc_tx_onestep_tstamp_init(struct enetc_ndev_priv *priv) -- 2.39.0