[syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7367539ad4b0 Merge tag 'cxl-fixes-6.9-rc7' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17c0a004980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3310e643b6ef5d69
dashboard link: https://syzkaller.appspot.com/bug?extid=b668da2bc4cb9670bf58
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/8b1efa4e7ecb/disk-7367539a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ba7142036852/vmlinux-7367539a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/17af3ae89832/bzImage-7367539a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com

mac80211_hwsim hwsim28 wlan0 (unregistering): left allmulticast mode
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0 Not tainted
------------------------------------------------------
kworker/u8:9/5208 is trying to acquire lock:
ffff88806325cd20 (team->team_lock_key#12){+.+.}-{3:3}, at: team_port_change_check drivers/net/team/team.c:2995 [inline]
ffff88806325cd20 (team->team_lock_key#12){+.+.}-{3:3}, at: team_device_event+0x11d/0x770 drivers/net/team/team.c:3021

but task is already holding lock:
ffff888051578768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5953 [inline]
ffff888051578768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_remove_interfaces+0xfe/0x760 net/mac80211/iface.c:2277

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rdev->wiphy.mtx){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       wiphy_lock include/net/cfg80211.h:5953 [inline]
       cfg80211_netdev_notifier_call+0x367/0x1110 net/wireless/core.c:1524
       notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
       call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1950
       call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
       call_netdevice_notifiers net/core/dev.c:2002 [inline]
       dev_open net/core/dev.c:1471 [inline]
       dev_open+0x144/0x160 net/core/dev.c:1459
       team_port_add drivers/net/team/team.c:1214 [inline]
       team_add_slave+0xadc/0x2110 drivers/net/team/team.c:1974
       do_set_master+0x1bc/0x230 net/core/rtnetlink.c:2685
       do_setlink+0xcaf/0x3ff0 net/core/rtnetlink.c:2891
       __rtnl_newlink+0xc35/0x1960 net/core/rtnetlink.c:3680
       rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3727
       rtnetlink_rcv_msg+0x3c7/0xe60 net/core/rtnetlink.c:6595
       netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2559
       netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
       netlink_unicast+0x542/0x820 net/netlink/af_netlink.c:1361
       netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1905
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg net/socket.c:745 [inline]
       ____sys_sendmsg+0xab5/0xc90 net/socket.c:2584
       ___sys_sendmsg+0x135/0x1e0 net/socket.c:2638
       __sys_sendmsg+0x117/0x1f0 net/socket.c:2667
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (team->team_lock_key#12){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       team_port_change_check drivers/net/team/team.c:2995 [inline]
       team_device_event+0x11d/0x770 drivers/net/team/team.c:3021
       notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
       call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1950
       call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
       call_netdevice_notifiers net/core/dev.c:2002 [inline]
       dev_close_many+0x333/0x6a0 net/core/dev.c:1543
       unregister_netdevice_many_notify+0x46d/0x19f0 net/core/dev.c:11080
       macvlan_device_event+0x4ed/0x880 drivers/net/macvlan.c:1828
       notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
       call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1950
       call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
       call_netdevice_notifiers net/core/dev.c:2002 [inline]
       unregister_netdevice_many_notify+0x8a1/0x19f0 net/core/dev.c:11105
       unregister_netdevice_many net/core/dev.c:11163 [inline]
       unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11042
       unregister_netdevice include/linux/netdevice.h:3115 [inline]
       _cfg80211_unregister_wdev+0x624/0x7f0 net/wireless/core.c:1206
       ieee80211_remove_interfaces+0x36d/0x760 net/mac80211/iface.c:2302
       ieee80211_unregister_hw+0x55/0x3a0 net/mac80211/main.c:1652
       mac80211_hwsim_del_radio drivers/net/wireless/virtual/mac80211_hwsim.c:5560 [inline]
       hwsim_exit_net+0x3ad/0x7d0 drivers/net/wireless/virtual/mac80211_hwsim.c:6437
       ops_exit_list+0xb0/0x180 net/core/net_namespace.c:170
       cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:637
       process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3267
       process_scheduled_works kernel/workqueue.c:3348 [inline]
       worker_thread+0x6c8/0xf70 kernel/workqueue.c:3429
       kthread+0x2c1/0x3a0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rdev->wiphy.mtx);
                               lock(team->team_lock_key#12);
                               lock(&rdev->wiphy.mtx);
  lock(team->team_lock_key#12);

 *** DEADLOCK ***

5 locks held by kworker/u8:9/5208:
 #0: ffff888015ecb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1296/0x1ac0 kernel/workqueue.c:3242
 #1: ffffc90003e5fd80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x906/0x1ac0 kernel/workqueue.c:3243
 #2: ffffffff8f2ec950 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xbb/0xbf0 net/core/net_namespace.c:591
 #3: ffffffff8f301748 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_unregister_hw+0x4d/0x3a0 net/mac80211/main.c:1645
 #4: ffff888051578768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5953 [inline]
 #4: ffff888051578768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_remove_interfaces+0xfe/0x760 net/mac80211/iface.c:2277

stack backtrace:
CPU: 1 PID: 5208 Comm: kworker/u8:9 Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
 team_port_change_check drivers/net/team/team.c:2995 [inline]
 team_device_event+0x11d/0x770 drivers/net/team/team.c:3021
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1950
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 dev_close_many+0x333/0x6a0 net/core/dev.c:1543
 unregister_netdevice_many_notify+0x46d/0x19f0 net/core/dev.c:11080
 macvlan_device_event+0x4ed/0x880 drivers/net/macvlan.c:1828
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1950
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 unregister_netdevice_many_notify+0x8a1/0x19f0 net/core/dev.c:11105
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11042
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 _cfg80211_unregister_wdev+0x624/0x7f0 net/wireless/core.c:1206
 ieee80211_remove_interfaces+0x36d/0x760 net/mac80211/iface.c:2302
 ieee80211_unregister_hw+0x55/0x3a0 net/mac80211/main.c:1652
 mac80211_hwsim_del_radio drivers/net/wireless/virtual/mac80211_hwsim.c:5560 [inline]
 hwsim_exit_net+0x3ad/0x7d0 drivers/net/wireless/virtual/mac80211_hwsim.c:6437
 ops_exit_list+0xb0/0x180 net/core/net_namespace.c:170
 cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:637
 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3267
 process_scheduled_works kernel/workqueue.c:3348 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3429
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
team0: Port device macvlan2 removed
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Interface deactivated: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Interface deactivated: batadv_slave_1
batman_adv: batadv0: Removing interface: batadv_slave_1
veth1_macvtap: left promiscuous mode
veth0_macvtap: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
team0 (unregistering): Port device virt_wifi0 removed
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed


---
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Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    1722389b0d86 Merge tag 'net-6.11-rc1' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11a8dabd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=381b8eb3d35e3ad9
dashboard link: https://syzkaller.appspot.com/bug?extid=b668da2bc4cb9670bf58
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=10e99275980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=137c299d980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-1722389b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3ad0b42d0812/vmlinux-1722389b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/67a851e0e5f8/bzImage-1722389b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com

netlink: 'syz-executor122': attribute type 10 has an invalid length.
dummy0: left promiscuous mode
dummy0: entered promiscuous mode
============================================
WARNING: possible recursive locking detected
6.10.0-syzkaller-12562-g1722389b0d86 #0 Not tainted
--------------------------------------------
syz-executor122/5360 is trying to acquire lock:
ffff88802c258d40 (team->team_lock_key){+.+.}-{3:3}, at: team_port_change_check drivers/net/team/team_core.c:2950 [inline]
ffff88802c258d40 (team->team_lock_key){+.+.}-{3:3}, at: team_device_event+0x2c7/0x770 drivers/net/team/team_core.c:2973

but task is already holding lock:
ffff88802c258d40 (team->team_lock_key){+.+.}-{3:3}, at: team_add_slave+0x9c/0x20e0 drivers/net/team/team_core.c:1975

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-executor122/5360:
 #0: ffffffff8fa1e9a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fa1e9a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644
 #1: ffff88802c258d40 (team->team_lock_key){+.+.}-{3:3}, at: team_add_slave+0x9c/0x20e0 drivers/net/team/team_core.c:1975

stack backtrace:
CPU: 0 UID: 0 PID: 5360 Comm: syz-executor122 Not tainted 6.10.0-syzkaller-12562-g1722389b0d86 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 check_deadlock kernel/locking/lockdep.c:3061 [inline]
 validate_chain kernel/locking/lockdep.c:3855 [inline]
 __lock_acquire+0x2167/0x3cb0 kernel/locking/lockdep.c:5142
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
 team_port_change_check drivers/net/team/team_core.c:2950 [inline]
 team_device_event+0x2c7/0x770 drivers/net/team/team_core.c:2973
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1994
 call_netdevice_notifiers_extack net/core/dev.c:2032 [inline]
 call_netdevice_notifiers net/core/dev.c:2046 [inline]
 __dev_notify_flags+0x12d/0x2e0 net/core/dev.c:8876
 dev_change_flags+0x10c/0x160 net/core/dev.c:8914
 vlan_device_event+0xdfc/0x2120 net/8021q/vlan.c:468
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1994
 call_netdevice_notifiers_extack net/core/dev.c:2032 [inline]
 call_netdevice_notifiers net/core/dev.c:2046 [inline]
 dev_open net/core/dev.c:1515 [inline]
 dev_open+0x144/0x160 net/core/dev.c:1503
 team_port_add drivers/net/team/team_core.c:1216 [inline]
 team_add_slave+0xacd/0x20e0 drivers/net/team/team_core.c:1976
 do_set_master+0x1bc/0x230 net/core/rtnetlink.c:2701
 do_setlink+0xcaf/0x3ff0 net/core/rtnetlink.c:2907
 __rtnl_newlink+0xc35/0x1960 net/core/rtnetlink.c:3696
 rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3743
 rtnetlink_rcv_msg+0x3c7/0xea0 net/core/rtnetlink.c:6647
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x544/0x830 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0xab5/0xc90 net/socket.c:2597
 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2651
 __sys_sendmsg+0x117/0x1f0 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f424ca7e7b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 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:00007ffd8c496978 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f424ca7e7b9
RDX: 0000000000000000 RSI: 0000000020000600 RDI: 0000000000000012
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffd8c4969a0
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/team/team_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..056889eff6b1 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -2947,7 +2947,7 @@ static void team_port_change_check(struct team_port *port, bool linkup)
 {
 	struct team *team = port->team;
 
-	mutex_lock(&team->lock);
+	mutex_lock_nested(&team->lock, 1);
 	__team_port_change_check(port, linkup);
 	mutex_unlock(&team->lock);
 }
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 net/core/rtnetlink.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 87e67194f240..178f5b85fd87 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2896,13 +2896,6 @@ static int do_setlink(const struct sk_buff *skb,
 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 	}
 
-	if (ifm->ifi_flags || ifm->ifi_change) {
-		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
-				       extack);
-		if (err < 0)
-			goto errout;
-	}
-
 	if (tb[IFLA_MASTER]) {
 		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
 		if (err)
@@ -2910,6 +2903,13 @@ static int do_setlink(const struct sk_buff *skb,
 		status |= DO_SETLINK_MODIFIED;
 	}
 
+	if (ifm->ifi_flags || ifm->ifi_change) {
+		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
+				       extack);
+		if (err < 0)
+			goto errout;
+	}
+
 	if (tb[IFLA_CARRIER]) {
 		err = dev_change_carrier(dev, nla_get_u8(tb[IFLA_CARRIER]));
 		if (err)
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master 

---
 drivers/net/team/team_core.c | 5 ++++-
 include/linux/if_team.h      | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..963c8311694f 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -1621,6 +1621,7 @@ static int team_init(struct net_device *dev)
 	team->dev = dev;
 	team_set_no_mode(team);
 	team->notifier_ctx = false;
+	team->nested_depth = 1;
 
 	team->pcpu_stats = netdev_alloc_pcpu_stats(struct team_pcpu_stats);
 	if (!team->pcpu_stats)
@@ -2947,8 +2948,10 @@ static void team_port_change_check(struct team_port *port, bool linkup)
 {
 	struct team *team = port->team;
 
-	mutex_lock(&team->lock);
+	mutex_lock_nested(&team->lock, team->nested_depth);
+	team->nested_depth++;
 	__team_port_change_check(port, linkup);
+	team->nested_depth--;
 	mutex_unlock(&team->lock);
 }
 
diff --git a/include/linux/if_team.h b/include/linux/if_team.h
index cdc684e04a2f..f8b4e3ed4b44 100644
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -225,6 +225,7 @@ struct team {
 	} mcast_rejoin;
 	struct lock_class_key team_lock_key;
 	long mode_priv[TEAM_MODE_PRIV_LONGS];
+	unsigned int nested_depth;
 };
 
 static inline int team_dev_queue_xmit(struct team *team, struct team_port *port,
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master 

---
 net/core/rtnetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 87e67194f240..dc9f9c4dcb49 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2903,7 +2903,7 @@ static int do_setlink(const struct sk_buff *skb,
 			goto errout;
 	}
 
-	if (tb[IFLA_MASTER]) {
+	if (tb[IFLA_MASTER] && !(dev->flags & IFF_UP)) {
 		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
 		if (err)
 			goto errout;
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master 

---
 drivers/net/team/team_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..ee595c3c6624 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -1212,8 +1212,9 @@ static int team_port_add(struct team *team, struct net_device *port_dev,
 			   portname);
 		goto err_port_enter;
 	}
-
+	mutex_unlock(&team->lock);
 	err = dev_open(port_dev, extack);
+	mutex_lock(&team->lock);
 	if (err) {
 		netdev_dbg(dev, "Device %s opening failed\n",
 			   portname);
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/team/team_core.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..44c709015007 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -2946,10 +2946,22 @@ static void __team_port_change_port_removed(struct team_port *port)
 static void team_port_change_check(struct team_port *port, bool linkup)
 {
 	struct team *team = port->team;
+	bool flag = true;
 
-	mutex_lock(&team->lock);
+	if (mutex_is_locked(&team->lock)){
+		unsigned owner, curr = (unsigned long)current;
+		owner = atomic_long_read(&team->lock.owner);
+		if (owner != curr)
+			mutex_lock(&team->lock);
+		else
+			flag = false;
+	}
+	else{
+		mutex_lock(&team->lock);
+	}
 	__team_port_change_check(port, linkup);
-	mutex_unlock(&team->lock);
+	if (flag)
+		mutex_unlock(&team->lock);
 }
 
 
--

Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@gmail.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 drivers/net/team/team_core.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..f7bab2d2a281 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -1668,7 +1668,6 @@ static void team_uninit(struct net_device *dev)
 	struct team_port *port;
 	struct team_port *tmp;
 
-	mutex_lock(&team->lock);
 	list_for_each_entry_safe(port, tmp, &team->port_list, list)
 		team_port_del(team, port->dev);
 
@@ -1677,7 +1676,6 @@ static void team_uninit(struct net_device *dev)
 	team_mcast_rejoin_fini(team);
 	team_notify_peers_fini(team);
 	team_queue_override_fini(team);
-	mutex_unlock(&team->lock);
 	netdev_change_features(dev);
 	lockdep_unregister_key(&team->team_lock_key);
 }
@@ -1818,7 +1816,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu)
 	 * Alhough this is reader, it's guarded by team lock. It's not possible
 	 * to traverse list in reverse under rcu_read_lock
 	 */
-	mutex_lock(&team->lock);
 	team->port_mtu_change_allowed = true;
 	list_for_each_entry(port, &team->port_list, list) {
 		err = dev_set_mtu(port->dev, new_mtu);
@@ -1829,7 +1826,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu)
 		}
 	}
 	team->port_mtu_change_allowed = false;
-	mutex_unlock(&team->lock);
 
 	WRITE_ONCE(dev->mtu, new_mtu);
 
@@ -1839,7 +1835,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu)
 	list_for_each_entry_continue_reverse(port, &team->port_list, list)
 		dev_set_mtu(port->dev, dev->mtu);
 	team->port_mtu_change_allowed = false;
-	mutex_unlock(&team->lock);
 
 	return err;
 }
@@ -1893,20 +1888,17 @@ static int team_vlan_rx_add_vid(struct net_device *dev, __be16 proto, u16 vid)
 	 * Alhough this is reader, it's guarded by team lock. It's not possible
 	 * to traverse list in reverse under rcu_read_lock
 	 */
-	mutex_lock(&team->lock);
 	list_for_each_entry(port, &team->port_list, list) {
 		err = vlan_vid_add(port->dev, proto, vid);
 		if (err)
 			goto unwind;
 	}
-	mutex_unlock(&team->lock);
 
 	return 0;
 
 unwind:
 	list_for_each_entry_continue_reverse(port, &team->port_list, list)
 		vlan_vid_del(port->dev, proto, vid);
-	mutex_unlock(&team->lock);
 
 	return err;
 }
@@ -1916,10 +1908,8 @@ static int team_vlan_rx_kill_vid(struct net_device *dev, __be16 proto, u16 vid)
 	struct team *team = netdev_priv(dev);
 	struct team_port *port;
 
-	mutex_lock(&team->lock);
 	list_for_each_entry(port, &team->port_list, list)
 		vlan_vid_del(port->dev, proto, vid);
-	mutex_unlock(&team->lock);
 
 	return 0;
 }
@@ -1941,9 +1931,7 @@ static void team_netpoll_cleanup(struct net_device *dev)
 {
 	struct team *team = netdev_priv(dev);
 
-	mutex_lock(&team->lock);
 	__team_netpoll_cleanup(team);
-	mutex_unlock(&team->lock);
 }
 
 static int team_netpoll_setup(struct net_device *dev,
@@ -1953,7 +1941,6 @@ static int team_netpoll_setup(struct net_device *dev,
 	struct team_port *port;
 	int err = 0;
 
-	mutex_lock(&team->lock);
 	list_for_each_entry(port, &team->port_list, list) {
 		err = __team_port_enable_netpoll(port);
 		if (err) {
@@ -1961,7 +1948,6 @@ static int team_netpoll_setup(struct net_device *dev,
 			break;
 		}
 	}
-	mutex_unlock(&team->lock);
 	return err;
 }
 #endif
@@ -1972,9 +1958,7 @@ static int team_add_slave(struct net_device *dev, struct net_device *port_dev,
 	struct team *team = netdev_priv(dev);
 	int err;
 
-	mutex_lock(&team->lock);
 	err = team_port_add(team, port_dev, extack);
-	mutex_unlock(&team->lock);
 
 	if (!err)
 		netdev_change_features(dev);
@@ -1987,9 +1971,7 @@ static int team_del_slave(struct net_device *dev, struct net_device *port_dev)
 	struct team *team = netdev_priv(dev);
 	int err;
 
-	mutex_lock(&team->lock);
 	err = team_port_del(team, port_dev);
-	mutex_unlock(&team->lock);
 
 	if (err)
 		return err;
@@ -2945,11 +2927,7 @@ static void __team_port_change_port_removed(struct team_port *port)
 
 static void team_port_change_check(struct team_port *port, bool linkup)
 {
-	struct team *team = port->team;
-
-	mutex_lock(&team->lock);
 	__team_port_change_check(port, linkup);
-	mutex_unlock(&team->lock);
 }
 
 
--

Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[Tetsuo Handa]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com
Tested-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com

Tested on:

commit:         2aeda959 Add linux-next specific files for 20250627
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=114daf0c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4db16d7e2cf94450
dashboard link: https://syzkaller.appspot.com/bug?extid=b668da2bc4cb9670bf58
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [net?] possible deadlock in team_device_event (3)

[Tetsuo Handa]

#syz fix: team: replace team lock with rtnl lock