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 98A1F13DB9F; Wed, 15 Jan 2025 15:49:50 +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=1736956190; cv=none; b=RhlXThjr8U0L6w2jqZTN1I7DX6VNj7ZRMcXI5h9nKNKDrYqB3iiZvYuo+hBzR4rne8tXPM/nd9dvHZLvA60nzLWSH1VVxMPZGoRsCd4wlia5UiJ8m6p4nZy+a4u2eqfTC9Onfjk642AazRUVeB3wCYifSMIPm22Zh426CCxztwg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736956190; c=relaxed/simple; bh=o8oTdXfpXYvKbpxgFeYHTBSgRC8ggH1Ckg7IIEgckBU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CS7RPLsjO9e+dTRQWZH4RD2k3don9Znt/lBJv90Lxz7Kf6fVr8ZGqpaeC4DMBgM9tAEO3PsvZ/fnR9K+Bm44DKcA0MtxYxQBjGNYGwPvOkPjpuEGPklBwMhjCDl/aIPRqoOGy/l1zswEJoeU74/Q+dlNgxGYION2y3QhJ6tBK1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bw7fG8P5; 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="bw7fG8P5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD3FAC4CED1; Wed, 15 Jan 2025 15:49:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736956190; bh=o8oTdXfpXYvKbpxgFeYHTBSgRC8ggH1Ckg7IIEgckBU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bw7fG8P5B2Mva+mwJtbpOiNImjI2SkLIMgsfSuxQk1av+wC3zU0v3QuvHJWYg4NJS SkrmJ9TlIrLLquMfoluAzOOTWFDJX6MK9xAr/l2vXfFwBPBu71H/lmsFmpifoIqhd5 FeFKNuY9mA0sIngGadxRP+F//aPQWnX/u9Iyqul6K7XuhAZ8BujqoAM6CYgIuXDEdg 8s5j0Q0oifrIIfEep7YulpjyCVF9rGouEILVgmMBO5n0Jc5w8uIdr51YvG/5q56TX2 X6grTHakXiYEu8sbwmk4yjR7W9/yzHSl3Di6LHGcDRBk00wmpp3C9ZnYFam6fqI3h9 KjBVMrJnbI8nA== Message-ID: <3c9bdd38-d60f-466d-a767-63f71368d41e@kernel.org> Date: Wed, 15 Jan 2025 17:49:44 +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> <8776a109-22c3-4c1e-a6a1-7bb0a4c70b06@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 12:38, Siddharth Vadapalli wrote: > On Wed, Jan 15, 2025 at 12:04:17PM +0200, Roger Quadros wrote: >> 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. > > Thank you for clarifying. So the issue/bug was discovered since the > implementation of am65_cpsw_nuss_update_tx_rx_chns(). The "Fixes" tag > misled me. Maybe the "Fixes" tag should be updated? Though we should > code to future-proof it as done in this patch, the "Fixes" tag pointing > to the very first commit of the driver might not be accurate as the > code-path associated with the bug cannot be exercised at that commit. Fair enough. I'll change the Fixes commit. > > Independent of the above change suggested for the "Fixes" tag, > > Reviewed-by: Siddharth Vadapalli > > There seems to be a different bug in am65_cpsw_nuss_update_tx_rx_chns() > which I have described below. > >> >> 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); > > The pair - am65_cpsw_nuss_init_tx_chns()/am65_cpsw_nuss_remove_tx_chns() > seem to be written under the assumption that failure will result in the > driver's probe failing. > > With am65_cpsw_nuss_update_tx_rx_chns(), that assumption no longer holds > true. Please consider the following sequence: > > 1. > am65_cpsw_nuss_probe() > am65_cpsw_nuss_register_ndevs() > am65_cpsw_nuss_init_tx_chns() => Succeeds > > 2. > Probe is successful > > 3. > am65_cpsw_nuss_update_tx_rx_chns() => Invoked by user > am65_cpsw_nuss_remove_tx_chns() => Succeeds > am65_cpsw_nuss_init_tx_chns() => Partially fails > devm_add_action(dev, am65_cpsw_nuss_free_tx_chns, common); > ^ DEVM Action is added, but since the driver isn't removed, > the cleanup via am65_cpsw_nuss_free_tx_chns() will not run. > > Only when the user re-invokes am65_cpsw_nuss_update_tx_rx_chns(), > the cleanup will be performed. This might have to be fixed in the > following manner: > > @@ -3416,10 +3416,17 @@ int am65_cpsw_nuss_update_tx_rx_chns(struct am65_cpsw_common *common, > common->tx_ch_num = num_tx; > common->rx_ch_num_flows = num_rx; > ret = am65_cpsw_nuss_init_tx_chns(common); > - if (ret) > + if (ret) { > + devm_remove_action(dev, am65_cpsw_nuss_free_tx_chns, common); > + am65_cpsw_nuss_free_tx_chns(common); > return ret; > + } > > ret = am65_cpsw_nuss_init_rx_chns(common); > + if (ret) { > + devm_remove_action(dev, am65_cpsw_nuss_free_rx_chns, common); > + am65_cpsw_nuss_free_rx_chns(common); > + } > > return ret; > } > > Please let me know what you think. I've already implemented a cleanup series to get rid of devm_add/remove_action, cleanup probe error path and streamline TX and RQ queue init/cleanup. I'll send out the series soon as soon as I finish some tests. -- cheers, -roger