[syzbot] [net?] WARNING in rtnl_dellink (3)

syzbot
2023-08-11T13:57:09Z

Hello,

syzbot found the following issue on:

HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15b02135a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1700ccaba80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bf6b84b5998f/disk-048c796b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4000dee89ebe/vmlinux-048c796b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b700ee9bd306/bzImage-048c796b.xz

The issue was bisected to:

commit 718cb09aaa6fa78cc8124e9517efbc6c92665384
Author: Vlad Buslov <vladbu@nvidia.com>
Date: Tue Aug 8 09:35:21 2023 +0000

vlan: Fix VLAN 0 memory leak

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1369e31da80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=10e9e31da80000
console output: https://syzkaller.appspot.com/x/log.txt?x=1769e31da80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b4f06495414e92701d5@syzkaller.appspotmail.com
Fixes: 718cb09aaa6f ("vlan: Fix VLAN 0 memory leak")

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5090 at net/core/dev.c:10876 unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Modules linked in:
CPU: 0 PID: 5090 Comm: syz-executor155 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Code: b4 1a 00 00 48 c7 c6 e0 18 81 8b 48 c7 c7 20 19 81 8b c6 05 ab 19 6c 06 01 e8 b4 22 23 f9 0f 0b e9 64 f7 ff ff e8 68 60 5c f9 <0f> 0b e9 3b f7 ff ff e8 fc 68 b0 f9 e9 fc ec ff ff 4c 89 e7 e8 4f
RSP: 0018:ffffc90003c4f158 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000028921a01 RCX: 0000000000000000
RDX: ffff888020503b80 RSI: ffffffff8829a7b8 RDI: 0000000000000001
RBP: ffff88807d990000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880274efe00
R13: 0000000000000000 R14: 0000000000000002 R15: ffff8880274efe00
FS: 0000555555fb0380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdeffb1328 CR3: 000000002a3a9000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2876b4cce9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdeffb1428 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2876b4cce9
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000004
RBP: 00000000000f4240 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000100000000 R11: 0000000000000246 R12: 00007ffdeffb1480
R13: 00000000000157a9 R14: 00007ffdeffb144c R15: 0000000000000003
</TASK>

---
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