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Date: Tue, 05 Mar 2024 14:44:21 -0800
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Message-ID: <0000000000004af86e0612f195c7@google.com>
Subject: Re: [syzbot] [net?] possible deadlock in team_port_change_check (2)
From: syzbot <syzbot+3c47b5843403a45aef57@syzkaller.appspotmail.com>
To: davem@davemloft.net, edumazet@google.com, jiri@resnulli.us, 
	kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, 
	pabeni@redhat.com, syzkaller-bugs@googlegroups.com, xrivendell7@gmail.com
Content-Type: text/plain; charset="UTF-8"

syzbot has found a reproducer for the following issue on:

HEAD commit:    885c36e59f46 net: Re-use and set mono_delivery_time bit fo..
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16c4c66c180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=92e06b597766606e
dashboard link: https://syzkaller.appspot.com/bug?extid=3c47b5843403a45aef57
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=15fe09f2180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=167cc5ee180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/241b626fcf71/disk-885c36e5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4f0f3e287f32/vmlinux-885c36e5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c31138ef60ba/bzImage-885c36e5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c47b5843403a45aef57@syzkaller.appspotmail.com

netlink: 'syz-executor286': attribute type 10 has an invalid length.
team0: Port device vlan1 added
netlink: 'syz-executor286': attribute type 10 has an invalid length.
veth0_vlan: left promiscuous mode
veth0_vlan: entered promiscuous mode
============================================
WARNING: possible recursive locking detected
6.8.0-rc6-syzkaller-01978-g885c36e59f46 #0 Not tainted
--------------------------------------------
syz-executor286/5073 is trying to acquire lock:
ffff888077f38d00 (team->team_lock_key){+.+.}-{3:3}, at: team_port_change_check+0x51/0x1e0 drivers/net/team/team.c:2995

but task is already holding lock:
ffff888077f38d00 (team->team_lock_key){+.+.}-{3:3}, at: team_add_slave+0xad/0x2750 drivers/net/team/team.c:1973

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(team->team_lock_key);
  lock(team->team_lock_key);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz-executor286/5073:
 #0: ffffffff8f378f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8f378f88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x842/0x10d0 net/core/rtnetlink.c:6595
 #1: ffff888077f38d00 (team->team_lock_key){+.+.}-{3:3}, at: team_add_slave+0xad/0x2750 drivers/net/team/team.c:1973

stack backtrace:
CPU: 0 PID: 5073 Comm: syz-executor286 Not tainted 6.8.0-rc6-syzkaller-01978-g885c36e59f46 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain+0x15c0/0x58e0 kernel/locking/lockdep.c:3856
 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 team_port_change_check+0x51/0x1e0 drivers/net/team/team.c:2995
 team_device_event+0x4e6/0x5b0 drivers/net/team/team.c:3018
 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93
 __dev_notify_flags+0x207/0x400
 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8773
 vlan_device_event+0x1b81/0x1de0 net/8021q/vlan.c:468
 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 dev_open+0x13a/0x1b0 net/core/dev.c:1471
 team_port_add drivers/net/team/team.c:1214 [inline]
 team_add_slave+0x9b3/0x2750 drivers/net/team/team.c:1974
 do_set_master net/core/rtnetlink.c:2688 [inline]
 do_setlink+0xe70/0x41f0 net/core/rtnetlink.c:2894
 rtnl_setlink+0x40d/0x5a0 net/core/rtnetlink.c:3188
 rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6598
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2547
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8e0/0xcb0 net/netlink/af_netlink.c:1902
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 sock_write_iter+0x2dd/0x400 net/socket.c:1160
 do_iter_readv_writev+0x46c/0x640
 vfs_writev+0x395/0xbb0 fs/read_write.c:971
 do_writev+0x1b1/0x350 fs/read_write.c:1018
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f5521197a89
Code: 48 83 c4 28 c3 e8 d7 19 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcaa0cf2c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f55211e53d3 RCX: 00007f5521197a89
RDX: 0000000000000001 RSI: 0000000020000040 RDI: 0000000000000004
RBP: 00007ffcaa0cf2f0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcaa0cf300
R13: 00007f55211e5004 R14: 00007ffcaa0cf2ec R15: 0000000000000003
 </TASK>


---
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