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 57D4F178381; Tue, 2 Jul 2024 17:17:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719940655; cv=none; b=QqRrwp7HmBCatay5p4lzkdRFp6JN9g/lvQxOZBNcuso0E8cNM3M86vaOXRxf4+fKl5lLUZKn+m5wIaZ/PPEuR2x2s8Z82kSaZ3GMaYtNIatrdMfOQQsA2xNv2nFqQCE/BgCydDi39o3dkjM5NbVcXSxHa6ACIa1sGWMLFTYqICo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719940655; c=relaxed/simple; bh=NKT3BTmVl4wLwKsJpJsmSGhS87zyan+gX9IfIm8L4Yo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jFHdZkVxkFywhfkrilqUgl/Z9TfYegBRLH943xBr3hc/2Pb8Bon8bP+2abx9n0LyRcIdSRFYfCpn8p+nhguevOKz6qzASgorVgx13UN/0s3l9/1GBZlJblH3eaf92oClTkFOJ0DETKsIaLIDL8LDQaqly4I2w6CLj8nAo3mgR9o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=efZ4naDf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="efZ4naDf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C02E1C116B1; Tue, 2 Jul 2024 17:17:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1719940655; bh=NKT3BTmVl4wLwKsJpJsmSGhS87zyan+gX9IfIm8L4Yo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=efZ4naDfCaN8AHSZqx2Yj2dVsZglY1yczd/kuxjIC4/KhKLTsbt49WT1fk81fIwy9 mUC44hNKjsx3y3sNhX6FiWZxWLXMihMCDeyPHJi3/TfTMT3Yk4qPVbY52faOwv2nbD L6GMvRQ9sKQ5WH4/1o3G12IeiJvnaczGUda7AL94= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vitor Soares , Marc Kleine-Budde Subject: [PATCH 6.9 189/222] can: mcp251xfd: fix infinite loop when xmit fails Date: Tue, 2 Jul 2024 19:03:47 +0200 Message-ID: <20240702170251.210368654@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240702170243.963426416@linuxfoundation.org> References: <20240702170243.963426416@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vitor Soares commit d8fb63e46c884c898a38f061c2330f7729e75510 upstream. When the mcp251xfd_start_xmit() function fails, the driver stops processing messages, and the interrupt routine does not return, running indefinitely even after killing the running application. Error messages: [ 441.298819] mcp251xfd spi2.0 can0: ERROR in mcp251xfd_start_xmit: -16 [ 441.306498] mcp251xfd spi2.0 can0: Transmit Event FIFO buffer not empty. (seq=0x000017c7, tef_tail=0x000017cf, tef_head=0x000017d0, tx_head=0x000017d3). ... and repeat forever. The issue can be triggered when multiple devices share the same SPI interface. And there is concurrent access to the bus. The problem occurs because tx_ring->head increments even if mcp251xfd_start_xmit() fails. Consequently, the driver skips one TX package while still expecting a response in mcp251xfd_handle_tefif_one(). Resolve the issue by starting a workqueue to write the tx obj synchronously if err = -EBUSY. In case of another error, decrement tx_ring->head, remove skb from the echo stack, and drop the message. Fixes: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN") Cc: stable@vger.kernel.org Signed-off-by: Vitor Soares Link: https://lore.kernel.org/all/20240517134355.770777-1-ivitro@gmail.com [mkl: use more imperative wording in patch description] Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 14 +++++- drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c | 55 +++++++++++++++++++++---- drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 5 ++ 3 files changed, 65 insertions(+), 9 deletions(-) --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c @@ -1618,11 +1618,20 @@ static int mcp251xfd_open(struct net_dev clear_bit(MCP251XFD_FLAGS_DOWN, priv->flags); can_rx_offload_enable(&priv->offload); + priv->wq = alloc_ordered_workqueue("%s-mcp251xfd_wq", + WQ_FREEZABLE | WQ_MEM_RECLAIM, + dev_name(&spi->dev)); + if (!priv->wq) { + err = -ENOMEM; + goto out_can_rx_offload_disable; + } + INIT_WORK(&priv->tx_work, mcp251xfd_tx_obj_write_sync); + err = request_threaded_irq(spi->irq, NULL, mcp251xfd_irq, IRQF_SHARED | IRQF_ONESHOT, dev_name(&spi->dev), priv); if (err) - goto out_can_rx_offload_disable; + goto out_destroy_workqueue; err = mcp251xfd_chip_interrupts_enable(priv); if (err) @@ -1634,6 +1643,8 @@ static int mcp251xfd_open(struct net_dev out_free_irq: free_irq(spi->irq, priv); + out_destroy_workqueue: + destroy_workqueue(priv->wq); out_can_rx_offload_disable: can_rx_offload_disable(&priv->offload); set_bit(MCP251XFD_FLAGS_DOWN, priv->flags); @@ -1661,6 +1672,7 @@ static int mcp251xfd_stop(struct net_dev hrtimer_cancel(&priv->tx_irq_timer); mcp251xfd_chip_interrupts_disable(priv); free_irq(ndev->irq, priv); + destroy_workqueue(priv->wq); can_rx_offload_disable(&priv->offload); mcp251xfd_timestamp_stop(priv); mcp251xfd_chip_stop(priv, CAN_STATE_STOPPED); --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c @@ -131,6 +131,39 @@ mcp251xfd_tx_obj_from_skb(const struct m tx_obj->xfer[0].len = len; } +static void mcp251xfd_tx_failure_drop(const struct mcp251xfd_priv *priv, + struct mcp251xfd_tx_ring *tx_ring, + int err) +{ + struct net_device *ndev = priv->ndev; + struct net_device_stats *stats = &ndev->stats; + unsigned int frame_len = 0; + u8 tx_head; + + tx_ring->head--; + stats->tx_dropped++; + tx_head = mcp251xfd_get_tx_head(tx_ring); + can_free_echo_skb(ndev, tx_head, &frame_len); + netdev_completed_queue(ndev, 1, frame_len); + netif_wake_queue(ndev); + + if (net_ratelimit()) + netdev_err(priv->ndev, "ERROR in %s: %d\n", __func__, err); +} + +void mcp251xfd_tx_obj_write_sync(struct work_struct *work) +{ + struct mcp251xfd_priv *priv = container_of(work, struct mcp251xfd_priv, + tx_work); + struct mcp251xfd_tx_obj *tx_obj = priv->tx_work_obj; + struct mcp251xfd_tx_ring *tx_ring = priv->tx; + int err; + + err = spi_sync(priv->spi, &tx_obj->msg); + if (err) + mcp251xfd_tx_failure_drop(priv, tx_ring, err); +} + static int mcp251xfd_tx_obj_write(const struct mcp251xfd_priv *priv, struct mcp251xfd_tx_obj *tx_obj) { @@ -162,6 +195,11 @@ static bool mcp251xfd_tx_busy(const stru return false; } +static bool mcp251xfd_work_busy(struct work_struct *work) +{ + return work_busy(work); +} + netdev_tx_t mcp251xfd_start_xmit(struct sk_buff *skb, struct net_device *ndev) { @@ -175,7 +213,8 @@ netdev_tx_t mcp251xfd_start_xmit(struct if (can_dev_dropped_skb(ndev, skb)) return NETDEV_TX_OK; - if (mcp251xfd_tx_busy(priv, tx_ring)) + if (mcp251xfd_tx_busy(priv, tx_ring) || + mcp251xfd_work_busy(&priv->tx_work)) return NETDEV_TX_BUSY; tx_obj = mcp251xfd_get_tx_obj_next(tx_ring); @@ -193,13 +232,13 @@ netdev_tx_t mcp251xfd_start_xmit(struct netdev_sent_queue(priv->ndev, frame_len); err = mcp251xfd_tx_obj_write(priv, tx_obj); - if (err) - goto out_err; - - return NETDEV_TX_OK; - - out_err: - netdev_err(priv->ndev, "ERROR in %s: %d\n", __func__, err); + if (err == -EBUSY) { + netif_stop_queue(ndev); + priv->tx_work_obj = tx_obj; + queue_work(priv->wq, &priv->tx_work); + } else if (err) { + mcp251xfd_tx_failure_drop(priv, tx_ring, err); + } return NETDEV_TX_OK; } --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h @@ -633,6 +633,10 @@ struct mcp251xfd_priv { struct mcp251xfd_rx_ring *rx[MCP251XFD_FIFO_RX_NUM]; struct mcp251xfd_tx_ring tx[MCP251XFD_FIFO_TX_NUM]; + struct workqueue_struct *wq; + struct work_struct tx_work; + struct mcp251xfd_tx_obj *tx_work_obj; + DECLARE_BITMAP(flags, __MCP251XFD_FLAGS_SIZE__); u8 rx_ring_num; @@ -952,6 +956,7 @@ void mcp251xfd_skb_set_timestamp(const s void mcp251xfd_timestamp_init(struct mcp251xfd_priv *priv); void mcp251xfd_timestamp_stop(struct mcp251xfd_priv *priv); +void mcp251xfd_tx_obj_write_sync(struct work_struct *work); netdev_tx_t mcp251xfd_start_xmit(struct sk_buff *skb, struct net_device *ndev);