Re: [syzbot] [net?] WARNING in dev_index_reserve

[syzbot <syzbot+5ba06978f34abb058571@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in dev_index_reserve

netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5448 at net/core/dev.c:9593 dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Modules linked in:
CPU: 0 PID: 5448 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-01605-g950fe35831af-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Code: 00 31 d2 4d 8d 45 50 b9 ff ff ff 7f 48 8d 74 24 20 e8 f2 05 02 02 4c 89 e7 89 c3 e8 48 01 11 02 e9 48 ff ff ff e8 5e 1a 5e f9 <0f> 0b bb ea ff ff ff e9 52 ff ff ff e8 cd 4f 0d 02 66 66 2e 0f 1f
RSP: 0018:ffffc9000623efa8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000000
RDX: ffff888029d59dc0 RSI: ffffffff88280632 RDI: 0000000000000005
RBP: 1ffff92000c47df5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: ffffffff8a40008b R12: ffff88802cd68010
R13: ffff888024e91d40 R14: ffff88802cd68000 R15: ffff88802cd680f8
FS:  00007f5beb1a96c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 0000000028632000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 register_netdevice+0x69a/0x1490 net/core/dev.c:10081
 veth_newlink+0x521/0xa50 drivers/net/veth.c:1938
 rtnl_newlink_create net/core/rtnetlink.c:3476 [inline]
 __rtnl_newlink+0x115e/0x18c0 net/core/rtnetlink.c:3693
 rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3706
 rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6432
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:728 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:751
 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2514
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2568
 __sys_sendmsg+0x117/0x1e0 net/socket.c:2597
 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: 0033:0x7f5bea47cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5beb1a90c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5bea59bf80 RCX: 00007f5bea47cae9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00007f5bea4c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f5bea59bf80 R15: 00007ffd991b5b58
 </TASK>


Tested on:

commit:         950fe358 Merge branch 'ipv6-expired-routes'
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16e89097a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fe63ad15dded26b6
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba06978f34abb058571
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17974440680000