From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38EA97E for ; Wed, 2 Nov 2022 02:36:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45F08C433C1; Wed, 2 Nov 2022 02:36:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667356613; bh=odvvt4Pt17S49uyYd0pBSLmAJEqluaT1iBPEJ4Vvjy4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SzX7XSmT4G8eAPsYM0KIMUMiabVLdWQaphyHy/ScP2rNev3eOrCuFe+qoIyNLTECH Iy8/9fMRC6MP/l0TTAYCgwWO68POyj7zJOxPFgEST+tN+xKk0r+XsjYLvOSTpPf7dq lwknI4vjkqs6hvbvnrcZR1yf7QuL1Nhn1yt4YBLM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marc Kleine-Budde , Biju Das Subject: [PATCH 6.0 004/240] can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive Date: Wed, 2 Nov 2022 03:29:39 +0100 Message-Id: <20221102022111.507354670@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221102022111.398283374@linuxfoundation.org> References: <20221102022111.398283374@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Biju Das 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 [mkl: adjust commit message] Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/rcar/rcar_canfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/net/can/rcar/rcar_canfd.c +++ b/drivers/net/can/rcar/rcar_canfd.c @@ -1157,11 +1157,13 @@ static void rcar_canfd_handle_global_rec { 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(gpriv, ridx)); - if (likely(sts & RCANFD_RFSTS_RFIF)) { + cc = rcar_canfd_read(priv->base, RCANFD_RFCC(gpriv, 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,