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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?xFB1DGY38nC19W6Ynn1gfp+cPUGl9UxIpxNifnJ5025qyR4uWktMLXljZo1L?= =?us-ascii?Q?e19k0oGvtf3nBqB3R1QOmtheYOZaw7/gmCm74EdILBiPuc2DXaxdIBHidF70?= =?us-ascii?Q?4g4+PWtX7IomHHj2jb04NkF1WHReadcb0PmcEEjuBvQOV3w9txspALr+T9tn?= =?us-ascii?Q?BRwkEpoDSZ5FLqaaORioutheKCV70lqI0xBjfMFFyArOPhr5uC5spGDDBS/N?= =?us-ascii?Q?Mrj5NytK4RrTKufuR+HTUDTHWd8ZXi6yDVXAHPEQaPBr0pVkHMSMKCuHOryS?= =?us-ascii?Q?PZPbnv8duIHQ4AeSU0qWvbADLQb42cLMDEjvL01LJM5BbPeJxZ1hPZP0q0/v?= =?us-ascii?Q?ECLyDmqoJ65tU70rTtQhHpNlmhpgSRfXk9QI+NnpIjXlXDULumdsjx1K0HTZ?= =?us-ascii?Q?C8tmdNeQpHiTEuWWlGODqbMF5kyflzjv9wS/Yqpgh4+YS76tDfJIw5v7FT6M?= =?us-ascii?Q?Zw/Sbp8unAaeIOnjyIiLbSFyX0TCFrl5UMjLIK3liaQ1f6QWScgiRzeNAQOn?= =?us-ascii?Q?IEPY0J2+RvzoqsiKe80iDhzqfSsMneJ3/U3wEzgtxYyJC9T6tkxl6v/oBygC?= =?us-ascii?Q?d3xy/T5S4nGsm5uX6Qe4wilgj6ZCehsLyD9VYlgEQYh6sX5MaLT9w8tslva4?= =?us-ascii?Q?lm+DPbM7UNRN8Xtmg81N29iO9keg6IiTWO2foiX8wbVBsdtD85CXS9Fph7rv?= =?us-ascii?Q?TJ+AAhR2whEFBTdNnCvjknGIdNb3BhRa446XzNbfLpP/Blud3EM+ruCtoMxy?= =?us-ascii?Q?IbbrfgPVNMTjtw3O1n+6DMhnW/LR/T8/EumFh2+HEhBN52PW4JtOXQa3iwMe?= =?us-ascii?Q?UHlwMKxC+3FzJUjsBqLdYBBlOnmdZ5Hun/xypvfkPYQNNOfARHD69eRoW1lU?= =?us-ascii?Q?CqC4eCIXZ6ldagfL5edOWzbkr1nEQ23gVKzZbJXLfTejvegkElFC/sLGn32D?= =?us-ascii?Q?xz59wmk/iWTqqDPbcZCpyjd1LnE9A1fVXDkjebG8vJpy/9qY4klzPrEU/eE4?= =?us-ascii?Q?6oiACsfkNBbpkDwP3gppWwgt/5DSxTNHEQXfIm+iwipsrhBzvorLYtqubW2P?= =?us-ascii?Q?Wth0Yxs48UzimE7dWMpcKHZ7CbcecnOaHCZoKXvs7gQWAgaqtL1v4YuScDsy?= =?us-ascii?Q?cSXSHnG7INYEMzLD/rm3ilNf2BpgDuG1Sy06zdjjQV9MfjTNcAHNGZBqo+OR?= =?us-ascii?Q?+5loWFkFwAODXoJH5/1UatWGWrvGLTOaFcKnztbugRvOflXAu2d2JU7iY5Zw?= =?us-ascii?Q?f3cV65ceSLg+O5Q5CffpqK2j3kaJW1Zi9fIwKWSuTmDMmqV0xGhnQ56BJaTZ?= =?us-ascii?Q?AeNUGDAmVD0VBN7JeB8e23XgCjwJPyniXrKLJaZdocr0nzbwxuOFv/76vhe6?= =?us-ascii?Q?maZURfihd1zoGwckTyK+U2ajctJEK8OwcLTVoLSo29xXTHO1WsOjuo86bucI?= =?us-ascii?Q?hrkgWaxLx4PshCuCx4Dc611gvV4K21EtrT5sepoTZzcD4Gfl5fBbTAcgKYjN?= =?us-ascii?Q?FR/2qPi4EQc3sHRDASgkANSpwxU27LLipFw7VIAHU+yva/anXa1yqXtWKMaj?= =?us-ascii?Q?IvnOFJDPg/+g1qmut+ogf2d/gGSRnpR90PfCJx22f6Z5DG97YRKuXzKOUTF5?= =?us-ascii?Q?tueOUGIB40H0E3HpB2EbijGZnh6xlmof38p6uQC/zOM0+KVVF/Vp1E9ZlpAK?= =?us-ascii?Q?D0bI9kq+tTRx8bonR21Z9mDvwsqsSJnzVA99HJOZJmAYsSn2sby+5sxc/NG4?= =?us-ascii?Q?/X23pCjpsg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 23dfe05a-320e-4293-24f9-08df2546777a X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB7957.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Oct 2026 14:14:29.3471 (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: Otco0y183CSXsXcpb7hjrbUosKO594lmImiGcNb8VLfTzIe/K7AffqNTHpkFePdk2tCC+bGX02VUjUNW0hWDpw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB8720 On Mon, Oct 05, 2026 at 10:12:27PM +0300, Anton Danilov wrote: > ip6gre_xmit_ipv6() drops an IPv6 packet whose source address equals the > tunnel remote, to avoid a trivial tunneling loop. On a collect_md > ip6gretap device t->parms.raddr is not the exit point: the outer > destination comes from the per-packet tunnel metadata. Such devices are > normally created without a remote, so raddr is ::, and the check never > matches a real tunnel endpoint. It matches every frame sent from the > unspecified address instead. > > On an L2 tunnel those frames are regular link traffic. Duplicate Address > Detection sends its Neighbor Solicitations from :: (RFC 4862, section > 5.4.2), and MLD reports are sent from :: while an interface has no > link-local address yet (RFC 3590, section 4). Frames bridged into a > collect_md ip6gretap device, e.g. with tc tunnel_key and mirred, are > dropped even though they carry valid metadata, so DAD cannot detect a > duplicate address on the other side of the tunnel. > > Skip the check for collect_md devices of type ARPHRD_ETHER. It stays for > L3 ip6gre, where sending a packet with an unspecified source means > forwarding it (RFC 4291, section 2.5.2), and for ip6gretap without > collect_md. ip6erspan does not run this check in collect_md mode either. > > Fixes: 6712abc168eb ("ip6_gre: add ip6 gre and gretap collect_md mode") > Cc: stable@vger.kernel.org > Assisted-by: LLM > Signed-off-by: Anton Danilov AFAICT, this isn't a regression, so for net-next: Reviewed-by: Ido Schimmel Jakub might agree to strip the tags before applying, so don't send v2 just yet. And if v2 is required, I would also drop the comment as it simply repeats the commit message.