Subject: [syzbot] [net?] WARNING in validate_chain

From: syzbot <[email-masked]>
Date: Wed, 27 Mar 2024 19:29:15 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    f99c5f563c17 Merge tag 'nf-24-03-21' of git://git.kernel.o..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=12a69546180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=6647fcd6542faf3abd06
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1549023a180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14c7b2a5180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/65d3f3eb786e/disk-f99c5f56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/799cf7f28ff8/vmlinux-f99c5f56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ab26c60c3845/bzImage-f99c5f56.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!irqs_disabled())
WARNING: CPU: 1 PID: 60 at kernel/locking/lockdep.c:150 lockdep_unlock+0x1e6/0x300 kernel/locking/lockdep.c:150
Modules linked in:
CPU: 1 PID: 60 Comm: kworker/u8:4 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:lockdep_unlock+0x1e6/0x300 kernel/locking/lockdep.c:150
Code: 0f b6 04 30 84 c0 0f 85 e4 00 00 00 83 3d 61 90 15 0e 00 75 19 90 48 c7 c7 c0 c0 aa 8b 48 c7 c6 00 c1 aa 8b e8 2b 78 e6 ff 90 <0f> 0b 90 90 90 e9 d2 fe ff ff 90 e8 0a a4 2f 03 85 c0 74 3a 48 c7
RSP: 0018:ffffc900015b6820 EFLAGS: 00010246
RAX: 3dc93ee123955000 RBX: 1ffff920002b6d08 RCX: ffff888017b1bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900015b68b0 R08: ffffffff8157cc12 R09: 1ffff110172a51a2
R10: dffffc0000000000 R11: ffffed10172a51a3 R12: 1ffff920002b6d04
R13: ffff888017b1c838 R14: dffffc0000000000 R15: ffffc900015b6840
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558bb644a7a0 CR3: 000000007a1d6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 graph_unlock kernel/locking/lockdep.c:186 [inline]
 validate_chain+0x15a2/0x58e0 kernel/locking/lockdep.c:3873
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
 seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline]
 read_seqbegin include/linux/seqlock.h:772 [inline]
 neigh_hh_output include/net/neighbour.h:496 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip_finish_output2+0x857/0x1380 net/ipv4/ip_output.c:235
 iptunnel_xmit+0x540/0x9b0 net/ipv4/ip_tunnel_core.c:82
 udp_tunnel_xmit_skb+0x234/0x350 net/ipv4/udp_tunnel_core.c:172
 geneve_xmit_skb drivers/net/geneve.c:910 [inline]
 geneve_xmit+0x1907/0x31a0 drivers/net/geneve.c:1030
 __netdev_start_xmit include/linux/netdevice.h:4903 [inline]
 netdev_start_xmit include/linux/netdevice.h:4917 [inline]
 xmit_one net/core/dev.c:3531 [inline]
 dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547
 __dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335
 neigh_output include/net/neighbour.h:542 [inline]
 ip6_finish_output2+0xff8/0x1670 net/ipv6/ip6_output.c:137
 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ndisc_send_skb+0xab0/0x1380 net/ipv6/ndisc.c:509
 ndisc_send_ns+0xcc/0x160 net/ipv6/ndisc.c:667
 addrconf_dad_work+0xb45/0x16f0 net/ipv6/addrconf.c:4279
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email-masked].

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup