From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 01142202C3C; Wed, 4 Dec 2024 17:45:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733334359; cv=none; b=HgZTzpYaRfmKGteZ8cdn4Zu4l9ntogvX87L46ZU+nFt+zwIZmLFbSVEi3RlVn11cVd1aMGZzTnjiPdeABxBrFRu6+sMt4NYaEL7l3yNTCJ4mRQiClfN9ELWEoeOAAxFih9oSqZQ3jKMPrf0xwFc6KfXd0TZzQZRGyoiDi1CDPsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733334359; c=relaxed/simple; bh=Doc8Gx3Y6QBxwLyndhlH+RaE0PYugcVjiBaorLoKlbs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PZi2QQ8dIiGqL/+Z1GRedFKFTYEZYDdeW7t6DXOFvdtlck6xsxJNGL67D9oiPcHyrTt1oAll+cmWI2Drf43TPRUfACm7pocNfAzLLaZxfb/wat/bGNy0NCP1yGIMhWFyo0WmMTEtKWpUBnLkbN/RxRa5QV3dqRQJ5JC3RjRt55Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=qj+2FVi7; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="qj+2FVi7" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=kzr64Zpl+/ODsxh5ngDaOioMCrFlk3ZIkJsAP9LIhGc=; b=qj+2FVi7MOovWbqbrtwMg0nY9z Uwx/AYN/X4CrTaCeYHsWhusd1x3YNjf5t5hpIM6gL/IMqt7g9JOlGXQwxI4XYW+g74VOfVr2lPTuC F21gQrknQ3AkNdIBQYNBwN/L1+6Xqw9D0Rfr33jCnwW+17ny7u0VxoMfR8v1k0T5+bd6NY7s2MIHy 6EzvqulNhPbrA+HLs4VqdStZ6Cn58D9Uiby0NM8aQg2NLEBuDTX770jvvu5iLtZfsoQb3gWDfAAgh YRITv9o2zSTyRJU2D10+HpL/qWHdFOKAyvUW36sPv81P0nj+n2SFUylPKCUZ7r/F/O1sL9ibzVxk3 5JtLW8Rg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:58250) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1tItRc-0003j0-1P; Wed, 04 Dec 2024 17:45:48 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1tItRY-0005jt-08; Wed, 04 Dec 2024 17:45:44 +0000 Date: Wed, 4 Dec 2024 17:45:43 +0000 From: "Russell King (Oracle)" To: Jon Hunter Cc: Thierry Reding , Robin Murphy , Furong Xu <0x1207@gmail.com>, Jakub Kicinski , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Torgue , Jose Abreu , "David S. Miller" , Eric Dumazet , Paolo Abeni , Maxime Coquelin , xfr@outlook.com, Suraj Jaiswal , Thierry Reding , "linux-tegra@vger.kernel.org" , Will Deacon Subject: Re: [PATCH net v1] net: stmmac: TSO: Fix unbalanced DMA map/unmap for non-paged SKB data Message-ID: References: <20241128144501.0000619b@gmail.com> <20241202163309.05603e96@kernel.org> <20241203100331.00007580@gmail.com> <20241202183425.4021d14c@kernel.org> <20241203111637.000023fe@gmail.com> <2g2lp3bkadc4wpeslmdoexpidoiqzt7vejar5xhjx5ayt3uox3@dqdyfzn6khn6> <9719982a-d40c-4110-9233-def2e6cb4d74@nvidia.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9719982a-d40c-4110-9233-def2e6cb4d74@nvidia.com> Sender: Russell King (Oracle) On Wed, Dec 04, 2024 at 05:02:19PM +0000, Jon Hunter wrote: > Hi Russell, > > On 04/12/2024 16:39, Russell King (Oracle) wrote: > > On Wed, Dec 04, 2024 at 04:58:34PM +0100, Thierry Reding wrote: > > > This doesn't match the location from earlier, but at least there's > > > something afoot here that needs fixing. I suppose this could simply be > > > hiding any subsequent errors, so once this is fixed we might see other > > > similar issues. > > > > Well, having a quick look at this, the first thing which stands out is: > > > > In stmmac_tx_clean(), we have: > > > > if (likely(tx_q->tx_skbuff_dma[entry].buf && > > tx_q->tx_skbuff_dma[entry].buf_type != STMMAC_TXBUF_T > > _XDP_TX)) { > > if (tx_q->tx_skbuff_dma[entry].map_as_page) > > dma_unmap_page(priv->device, > > tx_q->tx_skbuff_dma[entry].buf, > > tx_q->tx_skbuff_dma[entry].len, > > DMA_TO_DEVICE); > > else > > dma_unmap_single(priv->device, > > tx_q->tx_skbuff_dma[entry].buf, > > tx_q->tx_skbuff_dma[entry].len, > > DMA_TO_DEVICE); > > tx_q->tx_skbuff_dma[entry].buf = 0; > > tx_q->tx_skbuff_dma[entry].len = 0; > > tx_q->tx_skbuff_dma[entry].map_as_page = false; > > } > > > > So, tx_skbuff_dma[entry].buf is expected to point appropriately to the > > DMA region. > > > > Now if we look at stmmac_tso_xmit(): > > > > des = dma_map_single(priv->device, skb->data, skb_headlen(skb), > > DMA_TO_DEVICE); > > if (dma_mapping_error(priv->device, des)) > > goto dma_map_err; > > > > if (priv->dma_cap.addr64 <= 32) { > > ... > > } else { > > ... > > des += proto_hdr_len; > > ... > > } > > > > tx_q->tx_skbuff_dma[tx_q->cur_tx].buf = des; > > tx_q->tx_skbuff_dma[tx_q->cur_tx].len = skb_headlen(skb); > > tx_q->tx_skbuff_dma[tx_q->cur_tx].map_as_page = false; > > tx_q->tx_skbuff_dma[tx_q->cur_tx].buf_type = STMMAC_TXBUF_T_SKB; > > > > This will result in stmmac_tx_clean() calling dma_unmap_single() using > > "des" and "skb_headlen(skb)" as the buffer start and length. > > > > One of the requirements of the DMA mapping API is that the DMA handle > > returned by the map operation will be passed into the unmap function. > > Not something that was offset. The length will also be the same. > > > > We can clearly see above that there is a case where the DMA handle has > > been offset by proto_hdr_len, and when this is so, the value that is > > passed into the unmap operation no longer matches this requirement. > > > > So, a question to the reporter - what is the value of > > priv->dma_cap.addr64 in your failing case? You should see the value > > in the "Using %d/%d bits DMA host/device width" kernel message. > > It is ... > > dwc-eth-dwmac 2490000.ethernet: Using 40/40 bits DMA host/device width So yes, "des" is being offset, which will upset the unmap operation. Please try the following patch, thanks: diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 9b262cdad60b..c81ea8cdfe6e 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -4192,8 +4192,8 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) struct stmmac_txq_stats *txq_stats; struct stmmac_tx_queue *tx_q; u32 pay_len, mss, queue; + dma_addr_t tso_des, des; u8 proto_hdr_len, hdr; - dma_addr_t des; bool set_ic; int i; @@ -4289,14 +4289,15 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) /* If needed take extra descriptors to fill the remaining payload */ tmp_pay_len = pay_len - TSO_MAX_BUFF_SIZE; + tso_des = des; } else { stmmac_set_desc_addr(priv, first, des); tmp_pay_len = pay_len; - des += proto_hdr_len; + tso_des = des + proto_hdr_len; pay_len = 0; } - stmmac_tso_allocator(priv, des, tmp_pay_len, (nfrags == 0), queue); + stmmac_tso_allocator(priv, tso_des, tmp_pay_len, (nfrags == 0), queue); /* In case two or more DMA transmit descriptors are allocated for this * non-paged SKB data, the DMA buffer address should be saved to -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!