Message-ID: <684f719a.a00a0220.279073.0035.GAE@google.com>
Date: Sun, 15 Jun 2025 18:21:30 -0700
From: syzbot <syzbot+71fd22ae4b81631e22fd@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] possible deadlock in dev_set_allmulti (2)

Hello,

syzbot found the following issue on:

HEAD commit:    488ef3560196 KEYS: Invert FINAL_PUT bit
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ec3682580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=89df02a4e09cb64d
dashboard link: https://syzkaller.appspot.com/bug?extid=71fd22ae4b81631e22fd
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7b039b16a4b3/disk-488ef356.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3663fcbac4af/vmlinux-488ef356.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1941fbd3eaca/bzImage-488ef356.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+71fd22ae4b81631e22fd@...kaller.appspotmail.com

team_slave_0: entered allmulticast mode
team_slave_1: entered allmulticast mode
vlan2: entered allmulticast mode
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc1-syzkaller-00005-g488ef3560196 #0 Not tainted
------------------------------------------------------
syz.1.880/9004 is trying to acquire lock:
ffff888058130d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2756 [inline]
ffff888058130d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff888058130d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline]
ffff888058130d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_set_allmulti+0xa2/0x260 net/core/dev_api.c:312

but task is already holding lock:
ffff88805a2b4e00 (team->team_lock_key#5){+.+.}-{4:4}, at: team_change_rx_flags+0x39/0x220 drivers/net/team/team_core.c:1781

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (team->team_lock_key#5){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       team_port_change_check drivers/net/team/team_core.c:2966 [inline]
       team_device_event+0x11d/0x770 drivers/net/team/team_core.c:2992
       notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
       call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
       call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
       call_netdevice_notifiers net/core/dev.c:2282 [inline]
       dev_close_many+0x319/0x630 net/core/dev.c:1785
       vlan_device_event+0x1555/0x2290 net/8021q/vlan.c:449
       notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
       call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
       call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
       call_netdevice_notifiers net/core/dev.c:2282 [inline]
       __dev_notify_flags+0x1f7/0x2e0 net/core/dev.c:9499
       netif_change_flags+0x108/0x160 net/core/dev.c:9526
       do_setlink.constprop.0+0xb53/0x4380 net/core/rtnetlink.c:3141
       rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3927 [inline]
       rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4055
       rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
       netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg net/socket.c:727 [inline]
       ____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
       ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
       __sys_sendmsg+0x16d/0x220 net/socket.c:2652
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&dev_instance_lock_key#20){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain kernel/locking/lockdep.c:3911 [inline]
       __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
       lock_acquire kernel/locking/lockdep.c:5871 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       netdev_lock include/linux/netdevice.h:2756 [inline]
       netdev_lock_ops include/net/netdev_lock.h:42 [inline]
       netdev_lock_ops include/net/netdev_lock.h:39 [inline]
       dev_set_allmulti+0xa2/0x260 net/core/dev_api.c:312
       vlan_dev_change_rx_flags+0xb6/0x150 net/8021q/vlan_dev.c:472
       dev_change_rx_flags net/core/dev.c:9241 [inline]
       netif_set_allmulti+0x206/0x3d0 net/core/dev.c:9339
       dev_set_allmulti+0xb7/0x260 net/core/dev_api.c:313
       team_change_rx_flags+0x188/0x220 drivers/net/team/team_core.c:1789
       dev_change_rx_flags net/core/dev.c:9241 [inline]
       netif_set_allmulti+0x206/0x3d0 net/core/dev.c:9339
       __dev_change_flags+0x3d0/0x720 net/core/dev.c:9480
       netif_change_flags+0x8d/0x160 net/core/dev.c:9521
       do_setlink.constprop.0+0xb53/0x4380 net/core/rtnetlink.c:3141
       rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
       __rtnl_newlink net/core/rtnetlink.c:3927 [inline]
       rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4055
       rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
       netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg net/socket.c:727 [inline]
       ____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
       ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
       __sys_sendmsg+0x16d/0x220 net/socket.c:2652
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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(team->team_lock_key#5);
                               lock(&dev_instance_lock_key#20);
                               lock(team->team_lock_key#5);
  lock(&dev_instance_lock_key#20);

 *** DEADLOCK ***

2 locks held by syz.1.880/9004:
 #0: ffffffff9034cbe8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff9034cbe8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff9034cbe8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x2000 net/core/rtnetlink.c:4054
 #1: ffff88805a2b4e00 (team->team_lock_key#5){+.+.}-{4:4}, at: team_change_rx_flags+0x39/0x220 drivers/net/team/team_core.c:1781

stack backtrace:
CPU: 0 UID: 0 PID: 9004 Comm: syz.1.880 Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
 netdev_lock include/linux/netdevice.h:2756 [inline]
 netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 netdev_lock_ops include/net/netdev_lock.h:39 [inline]
 dev_set_allmulti+0xa2/0x260 net/core/dev_api.c:312
 vlan_dev_change_rx_flags+0xb6/0x150 net/8021q/vlan_dev.c:472
 dev_change_rx_flags net/core/dev.c:9241 [inline]
 netif_set_allmulti+0x206/0x3d0 net/core/dev.c:9339
 dev_set_allmulti+0xb7/0x260 net/core/dev_api.c:313
 team_change_rx_flags+0x188/0x220 drivers/net/team/team_core.c:1789
 dev_change_rx_flags net/core/dev.c:9241 [inline]
 netif_set_allmulti+0x206/0x3d0 net/core/dev.c:9339
 __dev_change_flags+0x3d0/0x720 net/core/dev.c:9480
 netif_change_flags+0x8d/0x160 net/core/dev.c:9521
 do_setlink.constprop.0+0xb53/0x4380 net/core/rtnetlink.c:3141
 rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3927 [inline]
 rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg net/socket.c:727 [inline]
 ____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
 __sys_sendmsg+0x16d/0x220 net/socket.c:2652
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f32b0f8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f32b1d85038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f32b11b5fa0 RCX: 00007f32b0f8e929
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007f32b1010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f32b11b5fa0 R15: 00007ffcfc6d21c8
 </TASK>
netdevsim netdevsim1 netdevsim0: entered allmulticast mode
dummy0: entered allmulticast mode
nlmon0: entered allmulticast mode
caif0: entered allmulticast mode
vxcan0: entered allmulticast mode
vxcan1: entered allmulticast mode
veth0: entered allmulticast mode
veth1: entered allmulticast mode
wg0: entered allmulticast mode
wg1: entered allmulticast mode
wg2: entered allmulticast mode
veth0_to_bridge: entered allmulticast mode
veth1_to_bridge: entered allmulticast mode
veth0_to_bond: entered allmulticast mode
veth1_to_bond: entered allmulticast mode
veth0_to_team: entered allmulticast mode
veth1_to_team: entered allmulticast mode
veth0_to_batadv: entered allmulticast mode
batadv_slave_0: entered allmulticast mode
veth1_to_batadv: entered allmulticast mode
batadv_slave_1: entered allmulticast mode
xfrm0: entered allmulticast mode
veth0_to_hsr: entered allmulticast mode
hsr_slave_0: entered allmulticast mode
veth1_to_hsr: entered allmulticast mode
hsr_slave_1: entered allmulticast mode
hsr0: entered allmulticast mode
veth1_virt_wifi: entered allmulticast mode
veth0_virt_wifi: entered allmulticast mode
net veth1_virt_wifi virt_wifi0: entered allmulticast mode
veth1_vlan: entered allmulticast mode
veth0_vlan: entered allmulticast mode
vlan0: entered allmulticast mode
vlan1: entered allmulticast mode
macvlan0: entered allmulticast mode
macvlan1: entered allmulticast mode
ipvlan0: entered allmulticast mode
ipvlan1: entered allmulticast mode
veth1_macvtap: entered allmulticast mode
veth0_macvtap: entered allmulticast mode
macvtap0: entered allmulticast mode
macsec0: entered allmulticast mode
geneve0: entered allmulticast mode
geneve1: entered allmulticast mode
netdevsim netdevsim1 netdevsim1: entered allmulticast mode
netdevsim netdevsim1 netdevsim2: entered allmulticast mode
netdevsim netdevsim1 netdevsim3: entered allmulticast mode
mac80211_hwsim hwsim6 wlan0: entered allmulticast mode
mac80211_hwsim hwsim7 wlan1: entered allmulticast mode
syztnl1: entered allmulticast mode
vxlan0: entered allmulticast mode
bond3: entered allmulticast mode
bridge1: entered allmulticast mode
macsec1: entered allmulticast mode


---
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See https://goo.gl/tpsmEJ for more information about syzbot.
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If the report is already addressed, let syzbot know by replying with:
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