From nobody Mon Jun 8 06:38:45 2026 Received: from rtits2.realtek.com.tw (rtits2.realtek.com [211.75.126.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2CC7B346777; Mon, 1 Jun 2026 06:24:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=211.75.126.72 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780295044; cv=none; b=DFZWJ7Z8rCmHA7XOZhNHRy1urzbTtxpsltIiZB15X6b4OSakRPWnzVosNGu6WHF6PsdsbsGXOaixqx65LhiR/KBRNa/K4+bRknHGDg2KGyLPXgHcZ0iTl15QVkv4zTZ4BnUCvJgkry2IhT1nya047/10InI/S1sruBkCM1boF0E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780295044; c=relaxed/simple; bh=Nw5ha/jTxyRROx0tiO/vQaPKOUIwZW8AYhOrNLxXrN4=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=YXuw8UzYtOIH4FJCAtFB0AXy0D1skstdxhFhcXzqSPd57UmX03437voLv/mq6UZMODMsPrp1TOLmcYZItHmwYarA+FYFHjIOnS86Cfe3SVZvuDllwRIlij2GtD6fv1iyU/2JaaGMhSz2txwueAfg9SM8GF+IzDru1KZivty+/4I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=realtek.com; spf=pass smtp.mailfrom=realtek.com; dkim=pass (2048-bit key) header.d=realtek.com header.i=@realtek.com header.b=TwxeBCDe; arc=none smtp.client-ip=211.75.126.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=realtek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=realtek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=realtek.com header.i=@realtek.com header.b="TwxeBCDe" X-SpamFilter-By: ArmorX SpamTrap 5.80 with qID 6516NhljE1861064, This message is accepted by code: ctloc85258 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=realtek.com; s=dkim; t=1780295023; bh=zGaiXVmbFcIR0uMWOBGPUlQVnflhuLNnVy3pOGlJPLM=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version: Content-Transfer-Encoding:Content-Type; b=TwxeBCDercioP+E+C2GwUL7QiH7g/bn3YOP/qfrOWJum1QPTr1o1xgDDM70Ptk7lN CsOfSz6LMYCSp1YNlPCO5DvECTtAoB4VjAlUiZ/mSFA6csSfDcNjz2PGO5XRQkAN0q 1VpVu3ykKmyIaIUhtEMSfBfgrLwZNY+dc8cjrN/R9vfd5ztwR0AM8goIo1nvQUN09V LMuO9DmOAAjyNtI6ijsYG5+KqrkJs4GxRr6lfe57rQ/096uWFZwYxj9CBgjmd6+3VQ vYIyRK49z1cYs141Bd+ltKCah1PqmGul+Ra+JhJzdiMWMW7Ozx2rRuRq3qXmxTC4U0 WBh9kdLNf1MaQ== Received: from mail.realtek.com (rtkexhmbs03.realtek.com.tw[10.21.1.53]) by rtits2.realtek.com.tw (8.15.2/3.28/5.94) with ESMTPS id 6516NhljE1861064 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 1 Jun 2026 14:23:43 +0800 Received: from RTKEXHMBS03.realtek.com.tw (10.21.1.53) by RTKEXHMBS03.realtek.com.tw (10.21.1.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Mon, 1 Jun 2026 14:23:43 +0800 Received: from RTDOMAIN (172.21.42.225) by RTKEXHMBS03.realtek.com.tw (10.21.1.53) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Mon, 1 Jun 2026 14:23:43 +0800 From: Justin Lai To: CC: , , , , , , , , , Justin Lai Subject: [PATCH] rtase: Workaround for IP fragmented UDP packet hardware bug Date: Mon, 1 Jun 2026 14:23:41 +0800 Message-ID: <20260601062341.63981-1-justinlai0215@realtek.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The hardware parser incorrectly interprets 319/320 in a short IP fragmented UDP packet payload as standard PTP destination ports and treats the fragment as a PTP packet for further parsing. If the transport data is smaller than RTASE_MIN_PAD_LEN, the remaining data is insufficient for further parsing and causes hardware TX hang. Pad these packets so the transport data reaches RTASE_MIN_PAD_LEN before transmitting to avoid triggering the hardware issue. Signed-off-by: Justin Lai --- drivers/net/ethernet/realtek/rtase/rtase.h | 3 ++ .../net/ethernet/realtek/rtase/rtase_main.c | 50 +++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/drivers/net/ethernet/realtek/rtase/rtase.h b/drivers/net/ether= net/realtek/rtase/rtase.h index 9bd6872474c1..213fe2173b40 100644 --- a/drivers/net/ethernet/realtek/rtase/rtase.h +++ b/drivers/net/ethernet/realtek/rtase/rtase.h @@ -363,4 +363,7 @@ struct rtase_private { =20 #define RTASE_MSS_MASK GENMASK(28, 18) =20 +#define RTASE_MIN_PAD_LEN 47 +#define RTASE_SHORT_PKT_THRESH 128 + #endif /* RTASE_H */ diff --git a/drivers/net/ethernet/realtek/rtase/rtase_main.c b/drivers/net/= ethernet/realtek/rtase/rtase_main.c index bde9bccfb5a9..43a4aa275b62 100644 --- a/drivers/net/ethernet/realtek/rtase/rtase_main.c +++ b/drivers/net/ethernet/realtek/rtase/rtase_main.c @@ -61,6 +61,7 @@ #include #include #include +#include #include #include #include @@ -1250,6 +1251,52 @@ static u32 rtase_tx_csum(struct sk_buff *skb, const = struct net_device *dev) return csum_cmd; } =20 +static bool rtase_skb_is_udp(struct sk_buff *skb) +{ + int no =3D skb_network_offset(skb); + struct ipv6hdr *i6h, _i6h; + struct iphdr *ih, _ih; + + switch (vlan_get_protocol(skb)) { + case htons(ETH_P_IP): + ih =3D skb_header_pointer(skb, no, sizeof(_ih), &_ih); + return ih && ih->protocol =3D=3D IPPROTO_UDP; + case htons(ETH_P_IPV6): + i6h =3D skb_header_pointer(skb, no, sizeof(_i6h), &_i6h); + return i6h && i6h->nexthdr =3D=3D IPPROTO_UDP; + default: + return false; + } +} + +static bool rtase_skb_pad(struct sk_buff *skb) +{ + bool has_trans =3D skb_transport_header_was_set(skb); + u32 pkt_len =3D skb->len; + u32 trans_data_len; + u16 dest_port; + u32 pad_len; + + if (!(has_trans && + pkt_len < RTASE_SHORT_PKT_THRESH + RTASE_MIN_PAD_LEN && + rtase_skb_is_udp(skb))) + return true; + + trans_data_len =3D skb_tail_pointer(skb) - skb_transport_header(skb); + if (trans_data_len >=3D offsetof(struct udphdr, len) && + trans_data_len < RTASE_MIN_PAD_LEN) { + dest_port =3D ntohs(udp_hdr(skb)->dest); + + if (dest_port =3D=3D PTP_EV_PORT || dest_port =3D=3D PTP_GEN_PORT) { + pad_len =3D RTASE_MIN_PAD_LEN - trans_data_len; + if (__skb_put_padto(skb, skb->len + pad_len, false)) + return false; + } + } + + return true; +} + static int rtase_xmit_frags(struct rtase_ring *ring, struct sk_buff *skb, u32 opts1, u32 opts2) { @@ -1363,6 +1410,9 @@ static netdev_tx_t rtase_start_xmit(struct sk_buff *s= kb, opts2 |=3D rtase_tx_csum(skb, dev); } =20 + if (!rtase_skb_pad(skb)) + goto err_dma_0; + frags =3D rtase_xmit_frags(ring, skb, opts1, opts2); if (unlikely(frags < 0)) goto err_dma_0; --=20 2.40.1