[v5.15] kernel BUG in eth_header (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10f9c49e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=a7b01390bf12a04bc291
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a7b013...@syzkaller.appspotmail.com

skbuff: skb_under_panic: text:ffffffff88034440 len:74 put:14 head:ffff888048da9800 data:ffff888048da97f2 tail:0x3c end:0xc0 dev:syz_tun
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:112!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8333 Comm: syz.4.1058 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:skb_panic+0x150/0x160 net/core/skbuff.c:112
Code: c7 20 fa 1e 8b 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 41 52 55 41 57 41 56 e8 54 13 f6 ff 48 83 c4 20 <0f> 0b 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 55 48 89 e5 41 57
RSP: 0018:ffffc90004f36ca0 EFLAGS: 00010286
RAX: 0000000000000087 RBX: dffffc0000000000 RCX: 9540746f03ee3c00
RDX: ffffc9000e1f9000 RSI: 000000000000489e RDI: 000000000000489f
RBP: 00000000000000c0 R08: ffff8880b9133d7f R09: 1ffff110172267af
R10: dffffc0000000000 R11: ffffed10172267b0 R12: ffff888048d163d0
R13: ffff888048da9800 R14: ffff888048da97f2 R15: 000000000000003c
FS: 00007f61c6fd86c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32c1eff8 CR3: 0000000048d00000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
skb_under_panic net/core/skbuff.c:122 [inline]
skb_push+0xba/0xd0 net/core/skbuff.c:2054
eth_header+0x30/0x200 net/ethernet/eth.c:82
dev_hard_header include/linux/netdevice.h:3305 [inline]
nf_send_reset6+0xc1d/0xff0 net/ipv6/netfilter/nf_reject_ipv6.c:384
nft_reject_inet_eval+0x325/0x680 net/netfilter/nft_reject_inet.c:48
expr_call_ops_eval net/netfilter/nf_tables_core.c:198 [inline]
nft_do_chain+0x491/0x14d0 net/netfilter/nf_tables_core.c:238
nft_do_chain_inet+0x25c/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584
nf_hook include/linux/netfilter.h:257 [inline]
NF_HOOK include/linux/netfilter.h:300 [inline]
br_nf_pre_routing_ipv6+0x53a/0x670 net/bridge/br_netfilter_ipv6.c:237
nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:242 [inline]
br_handle_frame+0xec1/0x10d0 net/bridge/br_input.c:384
__netif_receive_skb_core+0xfd5/0x3670 net/core/dev.c:5445
__netif_receive_skb_one_core net/core/dev.c:5549 [inline]
__netif_receive_skb+0x74/0x290 net/core/dev.c:5665
netif_receive_skb_internal net/core/dev.c:5751 [inline]
netif_receive_skb+0x19e/0x700 net/core/dev.c:5810
tun_rx_batched+0x606/0x760 drivers/net/tun.c:-1
tun_get_user+0x25bf/0x3b60 drivers/net/tun.c:1989
tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2019
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x748/0xd70 fs/read_write.c:594
ksys_write+0x153/0x260 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f61c8d406ce
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f61c6fd7fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f61c6fd86c0 RCX: 00007f61c8d406ce
RDX: 000000000000004a RSI: 0000200000000040 RDI: 00000000000000c8
RBP: 00007f61c8e15eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f61c9008038 R14: 00007f61c9007fa0 R15: 00007ffd7a935fa8
</TASK>
Modules linked in:
---[ end trace ff6ebf997eafdd42 ]---
RIP: 0010:skb_panic+0x150/0x160 net/core/skbuff.c:112
Code: c7 20 fa 1e 8b 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 41 52 55 41 57 41 56 e8 54 13 f6 ff 48 83 c4 20 <0f> 0b 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 55 48 89 e5 41 57
RSP: 0018:ffffc90004f36ca0 EFLAGS: 00010286
RAX: 0000000000000087 RBX: dffffc0000000000 RCX: 9540746f03ee3c00
RDX: ffffc9000e1f9000 RSI: 000000000000489e RDI: 000000000000489f
RBP: 00000000000000c0 R08: ffff8880b9133d7f R09: 1ffff110172267af
R10: dffffc0000000000 R11: ffffed10172267b0 R12: ffff888048d163d0
R13: ffff888048da9800 R14: ffff888048da97f2 R15: 000000000000003c
FS: 00007f61c6fd86c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32c1eff8 CR3: 0000000048d00000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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