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 AEE8026ED40; Wed, 28 Jan 2026 16:02:32 +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=1769616152; cv=none; b=O8v6PwF4Q0Q5oqJHq3Ur1x1qprKhN71nP0PY7OPvc+9I2/KfW3Ns9EEoTVXHtdmKnUJtxIeShGk5T0OJjzA1IsFosmvCIVpSIe2c97kF1/HW0tJA/WNuBRBJMvVlLpz5RpQjB8CTqMJLsbES0kcq/key+DERGzuhhNsIqqIlW8o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769616152; c=relaxed/simple; bh=DVJS4Vk27DLKjPYKaLt/pOcJ5X74VY4TxB3rXXhqofI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NnwQYa3LBhO8ea4EE3KnbeocXtf4fJLvELp7FBSJyTcWIcDHDNCNc16lCZSynZPa4vGQrg2VkqqO0RNBRP1QpL+0osWY3qD32XdLQqRWQzc7qjALNnlEn6qVy+tZHDLfyD45OIjVGZq55Pv+0pGN9QyP+o9m6lEEKtbee34Z9s0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OatCfXwn; 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="OatCfXwn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1910BC4CEF1; Wed, 28 Jan 2026 16:02:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769616152; bh=DVJS4Vk27DLKjPYKaLt/pOcJ5X74VY4TxB3rXXhqofI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OatCfXwn1QGDztmrN3rATypQ8LenoUcCvr+9L0ymPbEWxvLVvkHi4i+18q5yXAi9Y rbcc6FCZhNR7BnEVtjTRKxbXc0jhLhk0gVqehoHOMQIKn1/3oA72bmsMlIy4P/h3fK 0gCrVtFsk3VBOJEIiCxcZP++HhmaRKIsxhtN6L5M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Clemens Gruber , Wei Fang , Paolo Abeni , stable@kernel.org Subject: [PATCH 6.18 204/227] net: fec: account for VLAN header in frame length calculations Date: Wed, 28 Jan 2026 16:24:09 +0100 Message-ID: <20260128145351.779834565@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.331957407@linuxfoundation.org> References: <20260128145344.331957407@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Clemens Gruber commit ca1bb3fedf26a08ed31974131bc0064d4fe33649 upstream. The MAX_FL (maximum frame length) and related calculations used ETH_HLEN, which does not account for the 4-byte VLAN tag in tagged frames. This caused the hardware to reject valid VLAN frames as oversized, resulting in RX errors and dropped packets. Use VLAN_ETH_HLEN instead of ETH_HLEN in the MAX_FL register setup, cut-through mode threshold, buffer allocation, and max_mtu calculation. Cc: stable@kernel.org # v6.18+ Fixes: 62b5bb7be7bc ("net: fec: update MAX_FL based on the current MTU") Fixes: d466c16026e9 ("net: fec: enable the Jumbo frame support for i.MX8QM") Fixes: 59e9bf037d75 ("net: fec: add change_mtu to support dynamic buffer allocation") Fixes: ec2a1681ed4f ("net: fec: use a member variable for maximum buffer size") Signed-off-by: Clemens Gruber Reviewed-by: Wei Fang Link: https://patch.msgid.link/20260121083751.66997-1-mail@clemensgruber.at Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/freescale/fec_main.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1151,7 +1151,7 @@ fec_restart(struct net_device *ndev) u32 rcntl = FEC_RCR_MII; if (OPT_ARCH_HAS_MAX_FL) - rcntl |= (fep->netdev->mtu + ETH_HLEN + ETH_FCS_LEN) << 16; + rcntl |= (fep->netdev->mtu + VLAN_ETH_HLEN + ETH_FCS_LEN) << 16; if (fep->bufdesc_ex) fec_ptp_save_state(fep); @@ -1286,12 +1286,13 @@ fec_restart(struct net_device *ndev) /* When Jumbo Frame is enabled, the FIFO may not be large enough * to hold an entire frame. In such cases, if the MTU exceeds - * (PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN), configure the interface - * to operate in cut-through mode, triggered by the FIFO threshold. + * (PKT_MAXBUF_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN), configure + * the interface to operate in cut-through mode, triggered by + * the FIFO threshold. * Otherwise, enable the ENET store-and-forward mode. */ if ((fep->quirks & FEC_QUIRK_JUMBO_FRAME) && - (ndev->mtu > (PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN))) + (ndev->mtu > (PKT_MAXBUF_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN))) writel(0xF, fep->hwp + FEC_X_WMRK); else writel(FEC_TXWMRK_STRFWD, fep->hwp + FEC_X_WMRK); @@ -4052,7 +4053,7 @@ static int fec_change_mtu(struct net_dev if (netif_running(ndev)) return -EBUSY; - order = get_order(new_mtu + ETH_HLEN + ETH_FCS_LEN + order = get_order(new_mtu + VLAN_ETH_HLEN + ETH_FCS_LEN + FEC_DRV_RESERVE_SPACE); fep->rx_frame_size = (PAGE_SIZE << order) - FEC_DRV_RESERVE_SPACE; fep->pagepool_order = order; @@ -4609,7 +4610,7 @@ fec_probe(struct platform_device *pdev) else fep->max_buf_size = PKT_MAXBUF_SIZE; - ndev->max_mtu = fep->max_buf_size - ETH_HLEN - ETH_FCS_LEN; + ndev->max_mtu = fep->max_buf_size - VLAN_ETH_HLEN - ETH_FCS_LEN; ret = register_netdev(ndev); if (ret)