[syzbot] possible deadlock in team_del_slave

From: syzbot
Date: Mon Sep 20 2021 - 11:42:41 EST

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Hello,

syzbot found the following issue on:

HEAD commit: e57f52b42d1f Merge branch 'bpf: implement variadic printk ..
git tree: bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=143e16ab300000
kernel config: https://syzkaller.appspot.com/x/.config?x=6d93fe4341f98704
dashboard link: https://syzkaller.appspot.com/bug?extid=513e530ebfbfe5816cec
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+513e530ebfbfe5816cec@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
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

---
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Next message: Tim Gardner: "[PATCH][next] mptcp: Avoid NULL dereference in mptcp_getsockopt_subflow_addrs()"
Previous message: syzbot: "[syzbot] memory leak in prepare_kernel_cred"
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