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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?t/ErhB+Mp2Y6rkLyD7mOVcg9Bmo1aSRWSjkpa1FGkjamEuqh3Bnad2nG0SwZ?= =?us-ascii?Q?DbKW2bug+eGb+NczKMLl3it2Eqh27aijDKr+6SiV5RUUIkKMb01OoHruCRYO?= =?us-ascii?Q?mkHyKz8xkIU2FbNqR86Wkyaxx3j0gOsd3gasKNGdvRlFL+kxIIjcZp1vOzSe?= =?us-ascii?Q?E3UBU36vUTrD3I45mXTaBJFPqTtz2w8AbaEB1ZSv3r0zqXdptw48lAIT7Dra?= =?us-ascii?Q?dijCnkrOnoiXCbdpCKgJKFmBn9dsbaZp4TTouOhJ32mQq6sgod0SxJIucnkR?= =?us-ascii?Q?435beaIdOG7WE3nQpWUx9abb0riqxJSdvR+DeuGcQnKN+AWhZ5OlFbqqRscJ?= =?us-ascii?Q?3P5YY7tQ3AbVa/2PfXm5heVkaw0WV2o8IRUJii3jOrbOkG5xUExnZnylAJ/j?= =?us-ascii?Q?vYHkh25jcASVauwTp0Ukn2yWJvIdJAvvqhN/PS0DG5FRi9pXVxGp8Qw+rxXK?= =?us-ascii?Q?SNlVW1SCRL0JSvC4nUhAEXobcn2+LbOl/uceTfw1b7SDwqfdFQcUJpdiP+DJ?= =?us-ascii?Q?bnauNPuQ6fKAfoUfJn+zQagm6BSfOAXKCv0XVBL+CFx5/dMeM1i4HG+8UJUC?= =?us-ascii?Q?UugJNnsoMMvynfr9qNQif+5JqrqDAt/QYazgtA5aFrQ2uPXBxk7Og2QFZtPa?= =?us-ascii?Q?VHcU8GFZAAmt3v9A+UjbmGE4LZ1wxnCE7nIi1Buc6BDaeO5ohKQgg/G6XUL2?= =?us-ascii?Q?jGa+IBXa9iDIb9PNgtHB6rYUkNIf0af5qN9RusYVnaZY5CA+rpnyqd4UDAjq?= =?us-ascii?Q?liR8YOggvtA30ThoysIe0a5p6nVgqzQjoyRZkPl0NOv5rn5p0eguWPp4qOS7?= =?us-ascii?Q?RU1cdsTIbjJDTrpZmBv1YnrWza0QcJLBFZZBWBep7+pFyRLf2ME+hf5Nx6A8?= =?us-ascii?Q?5xhs4ZQNc2OE8Zg4rYZ/QhHSEaOAELWll9bl7XB24cPS2LbtpKWWbOYT1JNT?= =?us-ascii?Q?CoOWQjKOcKCc2ZVs8eGPiKfG4v8c4tvSzHfD1fdwYb7rgp8h4rgjwojz7QvY?= =?us-ascii?Q?HFuMo6WnBAJdVnP7Gil8Rhirlzci6HYWKh4JPd3MAbLJ6HZ/X09UbzQh738Y?= =?us-ascii?Q?V++bYYX1EKiAgKWOGWyYy30xryQJY30/HM0Th4u1ls2il+R+MKGsi09VO0Hn?= =?us-ascii?Q?biutDfiSuXTNzEQY6FW+Z8XerxcuBuL6mzlmcL0oYVYRtDsRaOSsxxSVahdX?= =?us-ascii?Q?Dr+AC5cIAWoyklOaovHuk/3QSPA23CWA/Ft1jhr1WiPfamteH1Y85COBuf+e?= =?us-ascii?Q?tyttC/az4KeLdvdgO9CtQT6wq3M5nuzIKZG7Wz3uRJ4m7/q+u1PnhvDtzHeo?= =?us-ascii?Q?O7n9+CNTDXq9JGXz8giWxBJ8bdllc+P5aejg4f1DUyRGbDpgjFYpTcSgikQN?= =?us-ascii?Q?SQ4To0MW+MDSZ2x7mcgo23B6jkLPVTUQ8nXLBIksfz9YAiByBfN+8TWj3d61?= =?us-ascii?Q?uCNzZm7rCOJ2hzKsk46IkqRH7tXUd1/pwfjH2XWJBb18g68LiTbsONb7ZJXz?= =?us-ascii?Q?9+WRHXKvGX19zOMPw0OibisfYwzLAQO75KtfljWdAlE0iMcgjaB3OjXMp1vD?= =?us-ascii?Q?rvEncmTh0M7/7xSATzFd6ExYPWzqHlqMxHSdr0tY2aAyXt4JBHfTFO5brUXW?= =?us-ascii?Q?tLrQg5zstAc7LndCDuFggYVcxgccQXvHtf15xfKPKIYcmuJsQ3YZRlawWZsF?= =?us-ascii?Q?gn1VmoHdhqacwl8l6sPLdnE2YHse95T0gsic5AF71ttCq5PiCqat+JRbDykq?= =?us-ascii?Q?Hp2xHhNBXg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: fdaf212d-5378-4f80-da5b-08dee19bb5e4 X-MS-Exchange-CrossTenant-AuthSource: SA3PR12MB7901.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Jul 2026 11:33:22.3165 (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: UNYWxI8KtHWi0Dy8Ud6AVeC8H1DDlyWhiv7A7ImM5Dwsa2xDr/WlaQ7w0IJiZaK+zJHnNaC4s0uc0ML9zz3VQQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB9197 On Mon, Jul 13, 2026 at 11:09:45PM +0800, Yun Zhou wrote: > Before commit 00d066a4d4ed ("netdev_features: convert NETIF_F_LLTX to > dev->lltx"), NETIF_F_LLTX was set unconditionally in both > __gre_tunnel_init() and ip6gre_tnl_init_features() alongside > GRE_FEATURES: > > dev->features |= GRE_FEATURES | NETIF_F_LLTX; > > When that commit converted NETIF_F_LLTX to the dev->lltx flag, it > placed 'dev->lltx = true' after the SEQ/CSUM early returns instead > of before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or > CSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition > around their ndo_start_xmit. Since GRE xmit re-enters the stack via > ip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the > underlay device. > > CPU0 CPU1 > ---- ---- > lock(&qdisc_xmit_lock_key#6); > lock(&qdisc_xmit_lock_key#3); > lock(&qdisc_xmit_lock_key#6); > lock(&qdisc_xmit_lock_key#3); > > Fix by moving dev->lltx = true before the early returns in both > functions, restoring the original unconditional behavior. > > Fixes: 00d066a4d4ed ("netdev_features: convert NETIF_F_LLTX to dev->lltx") > Signed-off-by: Yun Zhou Reviewed-by: Ido Schimmel