From patchwork Mon Oct 31 14:33:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Biju Das X-Patchwork-Id: 13025972 X-Patchwork-Delegate: kuba@kernel.org 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 59FC4FA3746 for ; Mon, 31 Oct 2022 14:34:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231638AbiJaOd7 (ORCPT ); Mon, 31 Oct 2022 10:33:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231666AbiJaOdf (ORCPT ); Mon, 31 Oct 2022 10:33:35 -0400 Received: from relmlie5.idc.renesas.com (relmlor1.renesas.com [210.160.252.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1F95C2DD6; Mon, 31 Oct 2022 07:33:23 -0700 (PDT) X-IronPort-AV: E=Sophos;i="5.95,228,1661785200"; d="scan'208";a="138526507" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 31 Oct 2022 23:33:23 +0900 Received: from localhost.localdomain (unknown [10.226.92.171]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id 3B32840065D4; Mon, 31 Oct 2022 23:33:18 +0900 (JST) From: Biju Das To: Wolfgang Grandegger , gregkh@linuxfoundation.org, Marc Kleine-Budde Cc: Biju Das , Lad Prabhakar , Pavel Machek , Sasha Levin , linux-can@vger.kernel.org, netdev@vger.kernel.org, Geert Uytterhoeven , Chris Paterson , linux-renesas-soc@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive Date: Mon, 31 Oct 2022 14:33:17 +0000 Message-Id: <20221031143317.938785-1-biju.das.jz@bp.renesas.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org commit 702de2c21eed04c67cefaaedc248ef16e5f6b293 upstream. We are seeing an IRQ storm on the global receive IRQ line under heavy CAN bus load conditions with both CAN channels enabled. Conditions: The global receive IRQ line is shared between can0 and can1, either of the channels can trigger interrupt while the other channel's IRQ line is disabled (RFIE). When global a receive IRQ interrupt occurs, we mask the interrupt in the IRQ handler. Clearing and unmasking of the interrupt is happening in rx_poll(). There is a race condition where rx_poll() unmasks the interrupt, but the next IRQ handler does not mask the IRQ due to NAPIF_STATE_MISSED flag (e.g.: can0 RX FIFO interrupt is disabled and can1 is triggering RX interrupt, the delay in rx_poll() processing results in setting NAPIF_STATE_MISSED flag) leading to an IRQ storm. This patch fixes the issue by checking IRQ active and enabled before handling the IRQ on a particular channel. Fixes: dd3bd23eb438 ("can: rcar_canfd: Add Renesas R-Car CAN FD driver") Suggested-by: Marc Kleine-Budde Signed-off-by: Biju Das Link: https://lore.kernel.org/all/20221025155657.1426948-2-biju.das.jz@bp.renesas.com Cc: stable@vger.kernel.org#5.15.y [mkl: adjust commit message] Signed-off-by: Marc Kleine-Budde [biju: removed gpriv from RCANFD_RFCC_RFIE macro] Signed-off-by: Biju Das --- Resending to 5.15 with confilcts[1] fixed [1] https://lore.kernel.org/stable/1667194204110137@kroah.com/T/#u --- drivers/net/can/rcar/rcar_canfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c index 2f44c567ebd7..9991bb475ae1 100644 --- a/drivers/net/can/rcar/rcar_canfd.c +++ b/drivers/net/can/rcar/rcar_canfd.c @@ -1106,11 +1106,13 @@ static void rcar_canfd_handle_global_receive(struct rcar_canfd_global *gpriv, u3 { struct rcar_canfd_channel *priv = gpriv->ch[ch]; u32 ridx = ch + RCANFD_RFFIFO_IDX; - u32 sts; + u32 sts, cc; /* Handle Rx interrupts */ sts = rcar_canfd_read(priv->base, RCANFD_RFSTS(ridx)); - if (likely(sts & RCANFD_RFSTS_RFIF)) { + cc = rcar_canfd_read(priv->base, RCANFD_RFCC(ridx)); + if (likely(sts & RCANFD_RFSTS_RFIF && + cc & RCANFD_RFCC_RFIE)) { if (napi_schedule_prep(&priv->napi)) { /* Disable Rx FIFO interrupts */ rcar_canfd_clear_bit(priv->base,