[moderation/CI] Re: net: clear transport header during tunnel decapsulation

[moderation/CI] Re: net: clear transport header during tunnel decapsulation

[syzbot ci]

syzbot ci has tested the following series

[v1] net: clear transport header during tunnel decapsulation
https://lore.kernel.org/all/20260624073209.3703492-1-edumazet@google.com
* [PATCH net] net: clear transport header during tunnel decapsulation

and found the following issue:
WARNING in geneve_udp_encap_recv

Full report is available here:
https://ci.syzbot.org/series/1f6dc47e-354f-4904-bc18-c2b7ea4d79b2

***

WARNING in geneve_udp_encap_recv

tree:      net
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net.git
base:      d87363b0edfc7504ff2b144fe4cdd8154f90f42e
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/7bb83c16-d55d-4d99-8c2b-6050e0022ef6/config

------------[ cut here ]------------
!skb_transport_header_was_set(skb)
WARNING: ./include/linux/skbuff.h:3094 at geneve_udp_encap_recv+0x26ed/0x4130, CPU#1: kworker/1:3/5072
Modules linked in:
CPU: 1 UID: 0 PID: 5072 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: mld mld_ifc_work
RIP: 0010:geneve_udp_encap_recv+0x26ed/0x4130
Code: c8 00 00 00 0f b6 04 01 84 c0 0f 85 f2 18 00 00 48 8b 7c 24 78 66 44 89 6f 0a e8 7e 9b 7a 03 e9 8c 00 00 00 e8 f4 fc 33 fb 90 <0f> 0b 90 e9 2e e3 ff ff 49 83 c6 06 4c 89 f0 48 c1 e8 03 48 b9 00
RSP: 0018:ffffc90000a08620 EFLAGS: 00010246
RAX: ffffffff8691f92c RBX: ffff8881bcc8b5d0 RCX: ffff88816a7abb80
RDX: 0000000000000100 RSI: 000000000000ffff RDI: 000000000000ffff
RBP: ffffc90000a08790 R08: ffffffff903114f7 R09: 1ffffffff206229e
R10: dffffc0000000000 R11: fffffbfff206229f R12: ffff888109f6a108
R13: 1ffff110213ed5df R14: 0000000000000010 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8882a927b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6956ea5440 CR3: 000000016f55c000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 udp_queue_rcv_one_skb+0xfc5/0x10e0
 udp_unicast_rcv_skb+0x21a/0x3a0
 udp_rcv+0xecb/0x1db0
 ip_protocol_deliver_rcu+0x27e/0x440
 ip_local_deliver_finish+0x3bb/0x6f0
 NF_HOOK+0x336/0x3c0
 NF_HOOK+0x336/0x3c0
 process_backlog+0xa34/0x1860
 __napi_poll+0xaa/0x330
 net_rx_action+0x61d/0xf50
 handle_softirqs+0x225/0x840
 do_softirq+0x76/0xd0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130
 __dev_queue_xmit+0x1ed7/0x37f0
 ip6_output+0x337/0x540
 NF_HOOK+0x177/0x4f0
 mld_sendpack+0x890/0xe10
 mld_ifc_work+0x839/0xe70
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

The email will later be sent to:
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If the report looks fine to you, reply with:
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If the report is a false positive, reply with
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Re: [moderation/CI] Re: net: clear transport header during tunnel decapsulation

[Aleksandr Nogikh]

#syz upstream

On Wed, Jun 24, 2026 at 1:48 PM syzbot ci
<syzbot+cic115a49afd959330@syzkaller.appspotmail.com> wrote:
>
> syzbot ci has tested the following series
>
> [v1] net: clear transport header during tunnel decapsulation
> https://lore.kernel.org/all/20260624073209.3703492-1-edumazet@google.com
> * [PATCH net] net: clear transport header during tunnel decapsulation
>
> and found the following issue:
> WARNING in geneve_udp_encap_recv
>
> Full report is available here:
> https://ci.syzbot.org/series/1f6dc47e-354f-4904-bc18-c2b7ea4d79b2
>
> ***
>
> WARNING in geneve_udp_encap_recv
>
> tree:      net
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net.git
> base:      d87363b0edfc7504ff2b144fe4cdd8154f90f42e
> arch:      amd64
> compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
> config:    https://ci.syzbot.org/builds/7bb83c16-d55d-4d99-8c2b-6050e0022ef6/config
>
> ------------[ cut here ]------------
> !skb_transport_header_was_set(skb)
> WARNING: ./include/linux/skbuff.h:3094 at geneve_udp_encap_recv+0x26ed/0x4130, CPU#1: kworker/1:3/5072
> Modules linked in:
> CPU: 1 UID: 0 PID: 5072 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> Workqueue: mld mld_ifc_work
> RIP: 0010:geneve_udp_encap_recv+0x26ed/0x4130
> Code: c8 00 00 00 0f b6 04 01 84 c0 0f 85 f2 18 00 00 48 8b 7c 24 78 66 44 89 6f 0a e8 7e 9b 7a 03 e9 8c 00 00 00 e8 f4 fc 33 fb 90 <0f> 0b 90 e9 2e e3 ff ff 49 83 c6 06 4c 89 f0 48 c1 e8 03 48 b9 00
> RSP: 0018:ffffc90000a08620 EFLAGS: 00010246
> RAX: ffffffff8691f92c RBX: ffff8881bcc8b5d0 RCX: ffff88816a7abb80
> RDX: 0000000000000100 RSI: 000000000000ffff RDI: 000000000000ffff
> RBP: ffffc90000a08790 R08: ffffffff903114f7 R09: 1ffffffff206229e
> R10: dffffc0000000000 R11: fffffbfff206229f R12: ffff888109f6a108
> R13: 1ffff110213ed5df R14: 0000000000000010 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff8882a927b000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f6956ea5440 CR3: 000000016f55c000 CR4: 00000000000006f0
> Call Trace:
>  <IRQ>
>  udp_queue_rcv_one_skb+0xfc5/0x10e0
>  udp_unicast_rcv_skb+0x21a/0x3a0
>  udp_rcv+0xecb/0x1db0
>  ip_protocol_deliver_rcu+0x27e/0x440
>  ip_local_deliver_finish+0x3bb/0x6f0
>  NF_HOOK+0x336/0x3c0
>  NF_HOOK+0x336/0x3c0
>  process_backlog+0xa34/0x1860
>  __napi_poll+0xaa/0x330
>  net_rx_action+0x61d/0xf50
>  handle_softirqs+0x225/0x840
>  do_softirq+0x76/0xd0
>  </IRQ>
>  <TASK>
>  __local_bh_enable_ip+0xf8/0x130
>  __dev_queue_xmit+0x1ed7/0x37f0
>  ip6_output+0x337/0x540
>  NF_HOOK+0x177/0x4f0
>  mld_sendpack+0x890/0xe10
>  mld_ifc_work+0x839/0xe70
>  process_scheduled_works+0xa8e/0x14e0
>  worker_thread+0xa47/0xfb0
>  kthread+0x388/0x470
>  ret_from_fork+0x514/0xb70
>  ret_from_fork_asm+0x1a/0x30
>  </TASK>
>
>
> ***
>
> If these findings have caused you to resend the series or submit a
> separate fix, please add the following tag to your commit message:
>   Tested-by: syzbot@syzkaller.appspotmail.com
>
> ---
> This report is generated by a bot. It may contain errors.
> syzbot ci engineers can be reached at syzkaller@googlegroups.com.
>
> To test a patch for this bug, please reply with `#syz test`
> (should be on a separate line).
>
> The patch should be attached to the email.
> Note: arguments like custom git repos and branches are not supported.
>
> The email will later be sent to:
> [davem@davemloft.net dsahern@kernel.org edumazet@google.com eric.dumazet@gmail.com horms@kernel.org idosch@nvidia.com kuba@kernel.org netdev@vger.kernel.org pabeni@redhat.com syzbot@syzkaller.appspotmail.com]
>
> If the report looks fine to you, reply with:
> #syz upstream
>
> If the report is a false positive, reply with
> #syz invalid
>
> --
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