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Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern , netdev@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH net-next] gre: fix ERSPAN o_flags race/corruption in xmit and fill_info Message-ID: <20260617063421.GA948096@shredder> References: <20260615140333.3161072-1-edumazet@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260615140333.3161072-1-edumazet@google.com> X-ClientProxiedBy: TLZP290CA0007.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:9::7) To SA3PR12MB7901.namprd12.prod.outlook.com (2603:10b6:806:306::12) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA3PR12MB7901:EE_|DS2PR12MB9773:EE_ X-MS-Office365-Filtering-Correlation-Id: d00d207d-2465-496c-2560-08decc3a7cd8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|23010399003|1800799024|3023799007|18002099003|22082099003|56012099006|11063799006; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?eT2DY5nk1h9LNGRNkyAyWn/EavlKrsj9MbNZ6/r+rSB8s9nwlTHqXgilHDob?= =?us-ascii?Q?6VPKh5+LM/0CuAGexD/z3LAtsCxBnLvivu4zJ/P8FugZA2ASK8hHYv2GspQI?= =?us-ascii?Q?5R/I5+Z7jIBrOnrEei2VfmAiLjLnMgntUkKkw6sRGG3zheryFZw1Rr+TJyt5?= =?us-ascii?Q?SOrIKT08DOWnd9hJ6elCOl2ZKwi3IJy8GT28VoeUaU4QcXg8ul2maUVSuOja?= =?us-ascii?Q?edol2sXjGRfW7vxc4naD/RbCEwOEIliHixIzgH6nwTkS3oSbwvdO3HkNp/qF?= =?us-ascii?Q?bjtI6niKpx6+vLK8qSawzF2rR/dhgrr9q+HQ/rOwbVXzm8sB1dO5/A0233yK?= =?us-ascii?Q?QdSbbj0OOOmNFtgXAONy3OcLOvEcsK+g6oDe5Ebuzs0wwe8xFF9a3Nh6+1SC?= =?us-ascii?Q?Fj1ZvXtGzUysDvykDg6TibPOJmd/SBr170CFO88zUkf+E4c1GupV0XBVZT9R?= =?us-ascii?Q?xWOft/oOvnQeq/igvlo8vqprBfXLBjfGNdr+1yQFsZ3YjvUpFYH5hIU/rlAW?= =?us-ascii?Q?2FuuzXlaimQ/aoQSV4+grB1BPqBi6tQp80KbJh8PfFdnypmBeFgLK5f4Hwmu?= =?us-ascii?Q?zTWgTyPuCI9ZUGeVXePfL0nMZYlOUvnHLb8g+guIqSbiX3Zqt0hJrsfPpq9D?= =?us-ascii?Q?ybG+2PGZ48xSGhm+Gip1v3IAIGd1F561G4KPS+2DrrMDVrljxR3fo8MqHFxI?= =?us-ascii?Q?I8e+pbXir5qSOsIgxESICbqJcq/FAnYpInV8ZhhJnnYHCsuv/b2cvEDwnSuO?= =?us-ascii?Q?5337ghArjHdVwUThkLarPzNprvkwFwCPKYI0OG0lgqdA9YD5Twe1OGoZrRx7?= =?us-ascii?Q?SPokRPmMPhzkdt8nMBfnbhXDaICxOq6DgtLa9wNWCCnnGsDaixiQKejiLjef?= =?us-ascii?Q?FlLXM+2S8u657Ac/11EBqtZVRi/TUzGVwzyw7toAyUvD0HiHb8uupRWhvFT5?= =?us-ascii?Q?DIKep+rxfqVqic327OPQ1th5rN+LxMO0SheB5s66ozKJz/GJWCyuV8vK/rph?= =?us-ascii?Q?YjhHfI6ICeOjMsSoSNhfdfvxSw05QpXq4o8W19yLP/uxpAPIF0nov5aGqT5Z?= =?us-ascii?Q?K8pex4opyMDU427483kWvbQHjcvSJMnCgR8lcXW18acM8mt8kdtDEDLqRrjO?= =?us-ascii?Q?Ce2CHZb9hrkQUo1wR0O8Bll73EBxwCFEk0jLzIyFBzNR9InSyPz2GNiWimgL?= =?us-ascii?Q?ppuUZvo+e9+tAwkAhDXlJSujuIuEDmwQ5kwwmwAii4S5S7hro9iGjDNFoGFi?= =?us-ascii?Q?U0QdNU3BQ6XmNyijgwKExhy/aRGF6wELHgyRMinfDls57CTALA9PyqaDuGFY?= =?us-ascii?Q?Ef4esaCPixDQ6h5WYDl/TIDGcAT2QBWzkXb2VuVg4ngWS7GGDdpnSHS5uMNP?= =?us-ascii?Q?c1TkGvlUHCm80U8ncdblm8w+fv1zcHE8k5vU+nuSH5aZWQBggYGUO8sxT9lO?= =?us-ascii?Q?TkGufPCmAEFlzPqVNfvFCDXyuchagGz8M2xTtxnpP3sxHDpJT3vlqGD+SyQP?= =?us-ascii?Q?vLQHF/w3NKwVo2khwhrik3d/XLlq3z7+jBOR4pjeEQnvmBoUWw6roqi46bAe?= =?us-ascii?Q?qP+1SsBOYLKNykwgf0BP4GkGwXh9/E8dN/q0olr9zxl0zvsXriXGlbMeIaOd?= =?us-ascii?Q?j9LL7E9MStbdqMxkWSNdWucX9jXC6I67Pl+gUq/AYZh9A3AOOxtSqrR3+V8i?= =?us-ascii?Q?Qz1EZU2OJFSxA0jCFOQVJTCkwTU0QHE3nIa3tuor7bVxeBvs?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: d00d207d-2465-496c-2560-08decc3a7cd8 X-MS-Exchange-CrossTenant-AuthSource: SA3PR12MB7901.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Jun 2026 06:34:31.0670 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: OM1JsaZI6R4hpjq1zn1uS0ssttQFcs2Yq0dJVs8yFM9gXhI4e69RY3eXHdQ1q+LD5ydum0H179kxC3qHN5gUhw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS2PR12MB9773 On Mon, Jun 15, 2026 at 02:03:33PM +0000, Eric Dumazet wrote: > @@ -692,7 +689,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb, > tunnel->parms.o_flags))) > goto free_skb; > > - __gre_xmit(skb, dev, tnl_params, skb->protocol); > + __gre_xmit(skb, dev, tnl_params, skb->protocol, tunnel->parms.o_flags); > return NETDEV_TX_OK; > > free_skb: > @@ -705,6 +702,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, > struct net_device *dev) > { > struct ip_tunnel *tunnel = netdev_priv(dev); > + IP_TUNNEL_DECLARE_FLAGS(flags); > bool truncate = false; > __be16 proto; > > @@ -728,10 +726,12 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, > truncate = true; > } > > + ip_tunnel_flags_copy(flags, tunnel->parms.o_flags); > + > /* Push ERSPAN header */ > if (tunnel->erspan_ver == 0) { > proto = htons(ETH_P_ERSPAN); > - __clear_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags); > + __clear_bit(IP_TUNNEL_SEQ_BIT, flags); > } else if (tunnel->erspan_ver == 1) { > erspan_build_header(skb, ntohl(tunnel->parms.o_key), > tunnel->index, > @@ -746,8 +746,8 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, > goto free_skb; > } > > - __clear_bit(IP_TUNNEL_KEY_BIT, tunnel->parms.o_flags); > - __gre_xmit(skb, dev, &tunnel->parms.iph, proto); > + __clear_bit(IP_TUNNEL_KEY_BIT, flags); > + __gre_xmit(skb, dev, &tunnel->parms.iph, proto, flags); > return NETDEV_TX_OK; > > free_skb: > @@ -776,7 +776,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb, > if (skb_cow_head(skb, dev->needed_headroom)) > goto free_skb; > > - __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB)); > + __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB), tunnel->parms.o_flags); Eric, did you see the feedback from Sashiko [1]? WDYT about aligning ipgre and gretap with erspan and passing a copy of the output flags to __gre_xmit() instead of passing 'tunnel->parms.o_flags' directly? The mismatch between the output flags and the tunnel header length is a different issue (pre-existing). [1] https://sashiko.dev/#/patchset/20260615140333.3161072-1-edumazet%40google.com > return NETDEV_TX_OK; > > free_skb: