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 480CE142E77; Tue, 17 Dec 2024 17:22:28 +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=1734456148; cv=none; b=S8hycrU90pZXiUsyt8tIFGYULXK+wz3cmNtdIXnQVqfbasKhwXRgdP156qn783cYU8fetppvkTV7cdaJffgwVixqmvSDbmu18n9lkq5iMqOuYcQizQC7BuAQmyCpH2+UJxj8Ejg8GjV2G4PUu2SrL/adOA1PJto+xfiwfUiSMjo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734456148; c=relaxed/simple; bh=V7H/+lg2VJq2/ksJ9tAsOAKrjCEwpJpsC1DbfKb7gRo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YqwxvAMLkWi22+Lagc9mJYTIqBMfYS/sJ4m4bLFIn3CQBbys5giA4VqutnLPqC3NgJgDxW4jNWSZI+oYVvEtYPilpGNNrBP/aRhM/wqk7+00Wg05C87FsZzImwMe3hYyYO7H0YoafS/IEDYHFiZPSBOhsObFyJufevmldVMchw8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X4j0cKP3; 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="X4j0cKP3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA75EC4CED3; Tue, 17 Dec 2024 17:22:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734456148; bh=V7H/+lg2VJq2/ksJ9tAsOAKrjCEwpJpsC1DbfKb7gRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X4j0cKP3XqPjyFOUTrNp+w8f6PdZVID5n304dd0AkMlt73WXmxM6QLw2uKrLYsTuF AIESYmHHnAUrKfUH3NsaV8pjuVyZ3p9Msi42fgSaYIBJyu3xbyE5txDCKdVyvMuTkA Fsg9FtbyhPV46IOLo09KvnL17DJJ9Kh60bBLhtwo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nikita Yushchenko , Yoshihiro Shimoda , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 077/109] net: renesas: rswitch: handle stop vs interrupt race Date: Tue, 17 Dec 2024 18:08:01 +0100 Message-ID: <20241217170536.599560553@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241217170533.329523616@linuxfoundation.org> References: <20241217170533.329523616@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikita Yushchenko [ Upstream commit 3dd002f20098b9569f8fd7f8703f364571e2e975 ] Currently the stop routine of rswitch driver does not immediately prevent hardware from continuing to update descriptors and requesting interrupts. It can happen that when rswitch_stop() executes the masking of interrupts from the queues of the port being closed, napi poll for that port is already scheduled or running on a different CPU. When execution of this napi poll completes, it will unmask the interrupts. And unmasked interrupt can fire after rswitch_stop() returns from napi_disable() call. Then, the handler won't mask it, because napi_schedule_prep() will return false, and interrupt storm will happen. This can't be fixed by making rswitch_stop() call napi_disable() before masking interrupts. In this case, the interrupt storm will happen if interrupt fires between napi_disable() and masking. Fix this by checking for priv->opened_ports bit when unmasking interrupts after napi poll. For that to be consistent, move priv->opened_ports changes into spinlock-protected areas, and reorder other operations in rswitch_open() and rswitch_stop() accordingly. Signed-off-by: Nikita Yushchenko Reviewed-by: Yoshihiro Shimoda Fixes: 3590918b5d07 ("net: ethernet: renesas: Add support for "Ethernet Switch"") Link: https://patch.msgid.link/20241209113204.175015-1-nikita.yoush@cogentembedded.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/renesas/rswitch.c | 33 ++++++++++++++------------ 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c index d04a79ece698..4dd218b6f308 100644 --- a/drivers/net/ethernet/renesas/rswitch.c +++ b/drivers/net/ethernet/renesas/rswitch.c @@ -839,8 +839,10 @@ static int rswitch_poll(struct napi_struct *napi, int budget) if (napi_complete_done(napi, budget - quota)) { spin_lock_irqsave(&priv->lock, flags); - rswitch_enadis_data_irq(priv, rdev->tx_queue->index, true); - rswitch_enadis_data_irq(priv, rdev->rx_queue->index, true); + if (test_bit(rdev->port, priv->opened_ports)) { + rswitch_enadis_data_irq(priv, rdev->tx_queue->index, true); + rswitch_enadis_data_irq(priv, rdev->rx_queue->index, true); + } spin_unlock_irqrestore(&priv->lock, flags); } @@ -1467,20 +1469,20 @@ static int rswitch_open(struct net_device *ndev) struct rswitch_device *rdev = netdev_priv(ndev); unsigned long flags; - phy_start(ndev->phydev); + if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS)) + iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDIE); napi_enable(&rdev->napi); - netif_start_queue(ndev); spin_lock_irqsave(&rdev->priv->lock, flags); + bitmap_set(rdev->priv->opened_ports, rdev->port, 1); rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, true); rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, true); spin_unlock_irqrestore(&rdev->priv->lock, flags); - if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS)) - iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDIE); + phy_start(ndev->phydev); - bitmap_set(rdev->priv->opened_ports, rdev->port, 1); + netif_start_queue(ndev); return 0; }; @@ -1492,7 +1494,16 @@ static int rswitch_stop(struct net_device *ndev) unsigned long flags; netif_tx_stop_all_queues(ndev); + + phy_stop(ndev->phydev); + + spin_lock_irqsave(&rdev->priv->lock, flags); + rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false); + rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false); bitmap_clear(rdev->priv->opened_ports, rdev->port, 1); + spin_unlock_irqrestore(&rdev->priv->lock, flags); + + napi_disable(&rdev->napi); if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS)) iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDID); @@ -1505,14 +1516,6 @@ static int rswitch_stop(struct net_device *ndev) kfree(ts_info); } - spin_lock_irqsave(&rdev->priv->lock, flags); - rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false); - rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false); - spin_unlock_irqrestore(&rdev->priv->lock, flags); - - phy_stop(ndev->phydev); - napi_disable(&rdev->napi); - return 0; }; -- 2.39.5