syzbot

netlink: 'syz-executor371': attribute type 10 has an invalid length.
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 Not tainted
------------------------------------------------------
syz-executor371/5855 is trying to acquire lock:
ffff888035d5ce00 (team->team_lock_key){+.+.}-{4:4}, at: team_port_change_check+0x51/0x1e0 drivers/net/team/team_core.c:2966

but task is already holding lock:
ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2751 [inline]
ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: do_setlink+0x3c1/0x4390 net/core/rtnetlink.c:3051

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&dev_instance_lock_key#3){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       netdev_lock include/linux/netdevice.h:2751 [inline]
       netdev_lock_ops include/net/netdev_lock.h:42 [inline]
       dev_set_mtu+0x11c/0x270 net/core/dev_api.c:246
       team_port_add drivers/net/team/team_core.c:1215 [inline]
       team_add_slave+0x83b/0x28b0 drivers/net/team/team_core.c:1989
       do_set_master+0x579/0x730 net/core/rtnetlink.c:2946
       do_setlink+0xf76/0x4390 net/core/rtnetlink.c:3159
       rtnl_changelink net/core/rtnetlink.c:3769 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
       rtnl_newlink+0x17e2/0x1fe0 net/core/rtnetlink.c:4065
       rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955
       netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg+0x221/0x270 net/socket.c:727
       ____sys_sendmsg+0x523/0x860 net/socket.c:2566
       ___sys_sendmsg net/socket.c:2620 [inline]
       __sys_sendmsg+0x271/0x360 net/socket.c:2652
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (team->team_lock_key){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       team_port_change_check+0x51/0x1e0 drivers/net/team/team_core.c:2966
       team_device_event+0x161/0x5b0 drivers/net/team/team_core.c:2992
       notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
       __dev_notify_flags+0x209/0x410 net/core/dev.c:-1
       netif_change_flags+0xf0/0x1a0 net/core/dev.c:9434
       do_setlink+0xee3/0x4390 net/core/rtnetlink.c:3152
       rtnl_changelink net/core/rtnetlink.c:3769 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
       rtnl_newlink+0x17e2/0x1fe0 net/core/rtnetlink.c:4065
       rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955
       netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg+0x221/0x270 net/socket.c:727
       ____sys_sendmsg+0x523/0x860 net/socket.c:2566
       ___sys_sendmsg net/socket.c:2620 [inline]
       __sys_sendmsg+0x271/0x360 net/socket.c:2652
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&dev_instance_lock_key#3);
                               lock(team->team_lock_key);
                               lock(&dev_instance_lock_key#3);
  lock(team->team_lock_key);

 *** DEADLOCK ***

2 locks held by syz-executor371/5855:
 #0: ffffffff900fd548 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff900fd548 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff900fd548 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xd68/0x1fe0 net/core/rtnetlink.c:4064
 #1: ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2751 [inline]
 #1: ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 #1: ffff8880364c6d30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: do_setlink+0x3c1/0x4390 net/core/rtnetlink.c:3051

stack backtrace:
CPU: 1 UID: 0 PID: 5855 Comm: syz-executor371 Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
 team_port_change_check+0x51/0x1e0 drivers/net/team/team_core.c:2966
 team_device_event+0x161/0x5b0 drivers/net/team/team_core.c:2992
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 __dev_notify_flags+0x209/0x410 net/core/dev.c:-1
 netif_change_flags+0xf0/0x1a0 net/core/dev.c:9434
 do_setlink+0xee3/0x4390 net/core/rtnetlink.c:3152
 rtnl_changelink net/core/rtnetlink.c:3769 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
 rtnl_newlink+0x17e2/0x1fe0 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:727
 ____sys_sendmsg+0x523/0x860 net/socket.c:2566
 ___sys_sendmsg net/socket.c:2620 [inline]
 __sys_sendmsg+0x271/0x360 net/socket.c:2652
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f325884b4d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 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:00007ffdbc9d2158 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f325884b4d9
RDX: 0000000000000000 RSI: 0000200000000600 RDI: 0000000000000003
RBP: 00007ffdbc9d2190 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000f4240
R13: 0000000000018e47 R14: 00007ffdbc9d2174 R15: 00007ffdbc9d2180
 </TASK>