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 BA15C2419F2; Wed, 15 Jan 2025 10:04:22 +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=1736935462; cv=none; b=So9CveQaU/7yLvBKn9ap4iLnlU9fF4pfVjJfcQNZPH/N08uSAP0dPJuSKec31NfzrqgsYazotDAveTLoJuKf2IYyMlH/yWSNJNzoDz8njtNo08nO1HigNgbdm+abCTgcD4LlFkF8eapTTisJwIVlMwCcvyaissa8OGbtCGHr3kw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736935462; c=relaxed/simple; bh=l5K1+6MX4+1I0AzQ9JSMUBIwyktKaJGh7IQj7QRRbu4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GNzY0+UegFxKNOKbF14G7LTVRi50xnDwD6E4juyW+5I9QRWTDUVwcz38P6LF5U5D5wBy1JzRppCNLzqd40Ko6px2zxebmn/Jrjg7xJKMWV3iCVE7whA20hsdqYU9JNi1L1g2wHRpYnCLJ8s2NSvxNmaNYNve/zWlwBvK7/wSZKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=utKsiDnp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="utKsiDnp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DA45C4CEE8; Wed, 15 Jan 2025 10:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736935462; bh=l5K1+6MX4+1I0AzQ9JSMUBIwyktKaJGh7IQj7QRRbu4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=utKsiDnpGZ/s/TmKp/OPQN5wV5Alm98n7DTUk0UeCLsbZCvFluBlTsjDtaT61xHM4 bMQYwp/Dc+BNrRsi5Se2Bgr3tzul6W3XHpAnD/hO9mH8O32HPKjK9uf0mfNYTr78aC q1suoZahyZyVvow8sWObC/AB8F+wjfna8uBRG6pNmEGI1PlXO94MWiGqjGv22WUPA2 AWw9apq1UkIJ9UAOdJKede27R+Jlh9WUvNM68abw5XZ++6NMeCYODNb7DxNXt9xXot mP2eX1UPjwVBppUG77KAJ2dqcMr7t4hECP3N1ceuVUrT8GAA/CS+AT3YKKOptd+6Ez tGPsuL4hjR1FA== Message-ID: <8776a109-22c3-4c1e-a6a1-7bb0a4c70b06@kernel.org> Date: Wed, 15 Jan 2025 12:04:17 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] net: ethernet: ti: am65-cpsw: fix freeing IRQ in am65_cpsw_nuss_remove_tx_chns() To: Siddharth Vadapalli Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Grygorii Strashko , srk@ti.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250114-am65-cpsw-fix-tx-irq-free-v1-1-b2069e6ed185@kernel.org> Content-Language: en-US From: Roger Quadros In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Siddharth, On 15/01/2025 07:18, Siddharth Vadapalli wrote: > On Tue, Jan 14, 2025 at 06:44:02PM +0200, Roger Quadros wrote: > > Hello Roger, > >> When getting the IRQ we use k3_udma_glue_rx_get_irq() which returns > > You probably meant "k3_udma_glue_tx_get_irq()" instead? It is used to > assign tx_chn->irq within am65_cpsw_nuss_init_tx_chns() as follows: Yes I meant tx instead of rx. > > tx_chn->irq = k3_udma_glue_tx_get_irq(tx_chn->tx_chn); > > Additionally, following the above section we have: > > if (tx_chn->irq < 0) { > dev_err(dev, "Failed to get tx dma irq %d\n", > tx_chn->irq); > ret = tx_chn->irq; > goto err; > } > > Could you please provide details on the code-path which will lead to a > negative "tx_chn->irq" within "am65_cpsw_nuss_remove_tx_chns()"? > > There seem to be two callers of am65_cpsw_nuss_remove_tx_chns(), namely: > 1. am65_cpsw_nuss_update_tx_rx_chns() > 2. am65_cpsw_nuss_suspend() > Since both of them seem to invoke am65_cpsw_nuss_remove_tx_chns() only > in the case where am65_cpsw_nuss_init_tx_chns() *did not* error out, it > appears to me that "tx_chn->irq" will never be negative within > am65_cpsw_nuss_remove_tx_chns() > > Please let me know if I have overlooked something. The issue is with am65_cpsw_nuss_update_tx_rx_chns(). It can be called repeatedly (by user changing number of TX queues) even if previous call to am65_cpsw_nuss_init_tx_chns() failed. Please try the below patch to simulate the error condition. Then do the following - bring down all network interfaces - change num TX queues to 2. IRQ for 2nd channel fails. - change num TX queues to 3. Now we try to free an invalid IRQ and we see warning. Also I think it is good practice to code for set value than to code for existing code paths as they can change in the future. --test patch starts-- diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c index 36c29d3db329..c22cadaaf3d3 100644 --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c @@ -155,7 +155,7 @@ NETIF_MSG_IFUP | NETIF_MSG_PROBE | NETIF_MSG_IFDOWN | \ NETIF_MSG_RX_ERR | NETIF_MSG_TX_ERR) -#define AM65_CPSW_DEFAULT_TX_CHNS 8 +#define AM65_CPSW_DEFAULT_TX_CHNS 1 #define AM65_CPSW_DEFAULT_RX_CHN_FLOWS 1 /* CPPI streaming packet interface */ @@ -2346,7 +2348,10 @@ static int am65_cpsw_nuss_init_tx_chns(struct am65_cpsw_common *common) tx_chn->dsize_log2 = __fls(hdesc_size_out); WARN_ON(hdesc_size_out != (1 << tx_chn->dsize_log2)); - tx_chn->irq = k3_udma_glue_tx_get_irq(tx_chn->tx_chn); + if (i == 1) + tx_chn->irq = -ENODEV; + else + tx_chn->irq = k3_udma_glue_tx_get_irq(tx_chn->tx_chn); if (tx_chn->irq < 0) { dev_err(dev, "Failed to get tx dma irq %d\n", tx_chn->irq); -- cheers, -roger