[syzbot] [net?] WARNING in qdisc_pkt_len_segs_init

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9c87e61e3c57 Merge tag 'bpf-next-7.2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d2901c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9a9f723a32776544
dashboard link: https://syzkaller.appspot.com/bug?extid=d5d0d598a4cfdfafdc3b
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5489ff1c0660/disk-9c87e61e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bcdabd5a8fea/vmlinux-9c87e61e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fa77e3b769c6/bzImage-9c87e61e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d5d0d5...@syzkaller.appspotmail.com

------------[ cut here ]------------
len > ((int)(~0U >> 1))
WARNING: ./include/linux/skbuff.h:2866 at pskb_may_pull_reason include/linux/skbuff.h:2866 [inline], CPU#0: syz.0.5520/24128
WARNING: ./include/linux/skbuff.h:2866 at pskb_may_pull include/linux/skbuff.h:2884 [inline], CPU#0: syz.0.5520/24128
WARNING: ./include/linux/skbuff.h:2866 at qdisc_pkt_len_segs_init+0x4b4/0xa30 net/core/dev.c:4138, CPU#0: syz.0.5520/24128
Modules linked in:
CPU: 0 UID: 0 PID: 24128 Comm: syz.0.5520 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pskb_may_pull_reason include/linux/skbuff.h:2866 [inline]
RIP: 0010:pskb_may_pull include/linux/skbuff.h:2884 [inline]
RIP: 0010:qdisc_pkt_len_segs_init+0x4b4/0xa30 net/core/dev.c:4138
Code: 00 00 02 00 31 ff e8 1b 3d 49 f8 81 e3 00 00 02 00 0f 85 fd 00 00 00 e8 ca 38 49 f8 45 89 e7 e9 2c ff ff ff e8 bd 38 49 f8 90 <0f> 0b 90 e9 ee fd ff ff 44 89 e7 89 de e8 6a 3a 49 f8 41 39 dc 0f
RSP: 0018:ffffc90000007660 EFLAGS: 00010246
RAX: ffffffff897ccc53 RBX: 0000000000000003 RCX: ffff8880761b8000
RDX: 0000000000000100 RSI: 00000000fffffffa RDI: 0000000000000000
RBP: ffff888034a70b40 R08: ffff88807bd48067 R09: 1ffff1100f7a900c
R10: dffffc0000000000 R11: ffffed100f7a900d R12: 00000000fffffffa
R13: dffffc0000000000 R14: 1ffff1100694e183 R15: ffff888068a29b98
FS: 00007f26d46806c0(0000) GS:ffff888125272000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 00000000894be000 CR4: 00000000003526f0
DR0: 0000000000000006 DR1: 0000000000000000 DR2: 000000007fffdff5
DR3: 0000800000000005 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
sch_handle_ingress net/core/dev.c:4479 [inline]
__netif_receive_skb_core+0x13aa/0x30b0 net/core/dev.c:6057
__netif_receive_skb_list_core+0x24d/0x830 net/core/dev.c:6281
__netif_receive_skb_list net/core/dev.c:6348 [inline]
netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6439
gro_normal_list include/net/gro.h:523 [inline]
gro_flush_normal include/net/gro.h:531 [inline]
napi_complete_done+0x299/0x730 net/core/dev.c:6807
gro_cell_poll+0x5ab/0x5d0 net/core/gro_cells.c:74
__napi_poll+0xaa/0x330 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:7949
handle_softirqs+0x225/0x840 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
</IRQ>
<TASK>
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
tun_rx_batched+0x616/0x790 drivers/net/tun.c:-1
tun_get_user+0x2b04/0x4350 drivers/net/tun.c:1986
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2032
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f26d379ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f26d4680028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f26d3a15fa0 RCX: 00007f26d379ce59
RDX: 000000000000fdef RSI: 00002000000002c0 RDI: 000000000000000a
RBP: 00007f26d3832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26d3a16038 R14: 00007f26d3a15fa0 R15: 00007f26d3b3fa48
</TASK>


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