From patchwork Mon Nov 27 12:24:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yoshihiro Shimoda X-Patchwork-Id: 13469471 X-Patchwork-Delegate: geert@linux-m68k.org Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from relmlie6.idc.renesas.com (relmlor2.renesas.com [210.160.252.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C8B9C13A; Mon, 27 Nov 2023 04:24:23 -0800 (PST) X-IronPort-AV: E=Sophos;i="6.04,230,1695654000"; d="scan'208";a="188255212" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie6.idc.renesas.com with ESMTP; 27 Nov 2023 21:24:22 +0900 Received: from localhost.localdomain (unknown [10.166.13.99]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id DEFC04009414; Mon, 27 Nov 2023 21:24:22 +0900 (JST) From: Yoshihiro Shimoda To: s.shtylyov@omp.ru, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Yoshihiro Shimoda Subject: [PATCH net v4] ravb: Fix races between ravb_tx_timeout_work() and net related ops Date: Mon, 27 Nov 2023 21:24:20 +0900 Message-Id: <20231127122420.3706751-1-yoshihiro.shimoda.uh@renesas.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-renesas-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Fix races between ravb_tx_timeout_work() and functions of net_device_ops and ethtool_ops by using rtnl_trylock() and rtnl_unlock(). Note that since ravb_close() is under the rtnl lock and calls cancel_work_sync(), ravb_tx_timeout_work() should calls rtnl_trylock(). Otherwise, a deadlock may happen in ravb_tx_timeout_work() like below: CPU0 CPU1 ravb_tx_timeout() schedule_work() ... __dev_close_many() // Under rtnl lock ravb_close() cancel_work_sync() // Waiting ravb_tx_timeout_work() rtnl_lock() // This is possible to cause a deadlock If rtnl_trylock() fails, rescheduling the work with sleep for 1 msec. Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper") Signed-off-by: Yoshihiro Shimoda Reviewed-by: Sergey Shtylyov --- Changes from v3: https://lore.kernel.org/all/20231115022644.2316961-1-yoshihiro.shimoda.uh@renesas.com/ - Based on v2 patch. This means that delayed work is not used. - Add rescheduling the work if rtnl_trylock() fails. - Drop Reviewed-by tags because implementation was changed. Changes from v2: https://lore.kernel.org/netdev/20231019113308.1133944-1-yoshihiro.shimoda.uh@renesas.com/ - Add rescheduling if rtnl_trylock() fails and the netif is still running and update commit description for it. - Add Reviewed-by tags. drivers/net/ethernet/renesas/ravb_main.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index c70cff80cc99..7c007ecd3ff6 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -1874,6 +1874,12 @@ static void ravb_tx_timeout_work(struct work_struct *work) struct net_device *ndev = priv->ndev; int error; + if (!rtnl_trylock()) { + usleep_range(1000, 2000); + schedule_work(&priv->work); + return; + } + netif_tx_stop_all_queues(ndev); /* Stop PTP Clock driver */ @@ -1907,7 +1913,7 @@ static void ravb_tx_timeout_work(struct work_struct *work) */ netdev_err(ndev, "%s: ravb_dmac_init() failed, error %d\n", __func__, error); - return; + goto out_unlock; } ravb_emac_init(ndev); @@ -1917,6 +1923,9 @@ static void ravb_tx_timeout_work(struct work_struct *work) ravb_ptp_init(ndev, priv->pdev); netif_tx_start_all_queues(ndev); + +out_unlock: + rtnl_unlock(); } /* Packet transmit function for Ethernet AVB */