possible deadlock in team_del_slave

Status: auto-closed as invalid on 2022/01/16 14:16
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+513e530ebfbfe5816cec@syzkaller.appspotmail.com
First crash: 1781d, last: 1781d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] possible deadlock in team_del_slave 0 (1) 2021/09/20 15:42
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in team_del_slave (2) net 4 35 1118d 1282d 0/29 auto-obsoleted due to no activity on 2023/09/28 12:50
linux-6.1 possible deadlock in team_del_slave origin:upstream missing-backport 4 syz, C inconclusive 77 12d 860d 0/3 upstream: reported C repro on 2024/03/27 10:53
linux-5.15 possible deadlock in team_del_slave (2) origin:lts-only 4 syz, C error 92 1d04h 934d 0/3 upstream: reported C repro on 2024/01/12 21:46
linux-6.6 possible deadlock in team_del_slave missing-backport origin:lts-only 4 syz, C inconclusive 26803 now 413d 0/2 upstream: reported C repro on 2025/06/16 19:00
upstream possible deadlock in team_del_slave (3) net 4 syz, C error 386707 346d 830d 29/29 fixed on 2025/09/04 16:57
linux-5.15 possible deadlock in team_del_slave 4 1 1207d 1207d 0/3 auto-obsoleted due to no activity on 2023/08/13 07:03

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.0-rc1-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/6377 is trying to acquire lock:
ffff888026c82cf8 (team->team_lock_key#5){+.+.}-{3:3}, at: team_del_slave+0x29/0x140 drivers/net/team/team.c:1981

but task is already holding lock:
ffff8880795b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: nl80211_del_interface+0xff/0x470 net/wireless/nl80211.c:4088

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:596 [inline]
       __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729
       wiphy_lock include/net/cfg80211.h:5311 [inline]
       ieee80211_open net/mac80211/iface.c:361 [inline]
       ieee80211_open+0x18f/0x240 net/mac80211/iface.c:348
       __dev_open+0x2bc/0x4d0 net/core/dev.c:1484
       dev_open net/core/dev.c:1520 [inline]
       dev_open+0xe8/0x150 net/core/dev.c:1513
       team_port_add drivers/net/team/team.c:1210 [inline]
       team_add_slave+0xaa4/0x1cc0 drivers/net/team/team.c:1967
       do_set_master+0x1c8/0x220 net/core/rtnetlink.c:2521
       do_setlink+0x9f3/0x3970 net/core/rtnetlink.c:2726
       __rtnl_newlink+0xde6/0x1750 net/core/rtnetlink.c:3391
       rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3506
       rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572
       netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
       netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
       netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
       netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
       sock_sendmsg_nosec net/socket.c:704 [inline]
       sock_sendmsg+0xcf/0x120 net/socket.c:724
       ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
       ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
       __sys_sendmsg+0xf3/0x1c0 net/socket.c:2492
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (team->team_lock_key#5){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
       lock_acquire kernel/locking/lockdep.c:5625 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
       __mutex_lock_common kernel/locking/mutex.c:596 [inline]
       __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729
       team_del_slave+0x29/0x140 drivers/net/team/team.c:1981
       team_device_event+0x7df/0xa90 drivers/net/team/team.c:3004
       notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
       call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1996
       call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
       call_netdevice_notifiers net/core/dev.c:2022 [inline]
       unregister_netdevice_many+0x951/0x1790 net/core/dev.c:11041
       unregister_netdevice_queue+0x2dd/0x3c0 net/core/dev.c:10975
       unregister_netdevice include/linux/netdevice.h:2988 [inline]
       _cfg80211_unregister_wdev+0x483/0x770 net/wireless/core.c:1125
       ieee80211_if_remove+0x1df/0x380 net/mac80211/iface.c:2088
       ieee80211_del_iface+0x12/0x20 net/mac80211/cfg.c:144
       rdev_del_virtual_intf net/wireless/rdev-ops.h:57 [inline]
       nl80211_del_interface+0x1b2/0x470 net/wireless/nl80211.c:4090
       genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
       genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
       genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
       netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
       netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
       netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
       netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
       sock_sendmsg_nosec net/socket.c:704 [inline]
       sock_sendmsg+0xcf/0x120 net/socket.c:724
       ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
       ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
       __sys_sendmsg+0xf3/0x1c0 net/socket.c:2492
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rdev->wiphy.mtx);
                               lock(team->team_lock_key#5);
                               lock(&rdev->wiphy.mtx);
  lock(team->team_lock_key#5);

 *** DEADLOCK ***

3 locks held by syz-executor.4/6377:
 #0: ffffffff8d177290 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8d0e3f28 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x23/0x620 net/wireless/nl80211.c:14927
 #2: ffff8880795b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: nl80211_del_interface+0xff/0x470 net/wireless/nl80211.c:4088

stack backtrace:
CPU: 0 PID: 6377 Comm: syz-executor.4 Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131
 check_prev_add kernel/locking/lockdep.c:3051 [inline]
 check_prevs_add kernel/locking/lockdep.c:3174 [inline]
 validate_chain kernel/locking/lockdep.c:3789 [inline]
 __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
 lock_acquire kernel/locking/lockdep.c:5625 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
 __mutex_lock_common kernel/locking/mutex.c:596 [inline]
 __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729
 team_del_slave+0x29/0x140 drivers/net/team/team.c:1981
 team_device_event+0x7df/0xa90 drivers/net/team/team.c:3004
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1996
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers net/core/dev.c:2022 [inline]
 unregister_netdevice_many+0x951/0x1790 net/core/dev.c:11041
 unregister_netdevice_queue+0x2dd/0x3c0 net/core/dev.c:10975
 unregister_netdevice include/linux/netdevice.h:2988 [inline]
 _cfg80211_unregister_wdev+0x483/0x770 net/wireless/core.c:1125
 ieee80211_if_remove+0x1df/0x380 net/mac80211/iface.c:2088
 ieee80211_del_iface+0x12/0x20 net/mac80211/cfg.c:144
 rdev_del_virtual_intf net/wireless/rdev-ops.h:57 [inline]
 nl80211_del_interface+0x1b2/0x470 net/wireless/nl80211.c:4090
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
 __sys_sendmsg+0xf3/0x1c0 net/socket.c:2492
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ff117663739
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff114bda188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff117767f80 RCX: 00007ff117663739
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007ff1176bdcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff117767f80
R13: 00007ffdd3545d8f R14: 00007ff114bda300 R15: 0000000000022000
device wlan9 left promiscuous mode
team0: Port device wlan9 removed

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/09/18 14:16 bpf-next e57f52b42d1f 70b76c1d .config console log report info ci-upstream-bpf-next-kasan-gce possible deadlock in team_del_slave
* Struck through repros no longer work on HEAD.