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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 480e035fc4c7 Merge tag 'drm-next-2024-03-13' of https://gi..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1662179e180000
kernel config: https://syzkaller.appspot.com/x/.config?x=1e5b814e91787669
dashboard link: https://syzkaller.appspot.com/bug?extid=705c61d60b091ef42c04
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=1058e7b9180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11919365180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5f73b6ef963d/disk-480e035f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/46c949396aad/vmlinux-480e035f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e3b4d0f5a5f8/bzImage-480e035f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+705c61...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.8.0-syzkaller-08073-g480e035fc4c7 #0 Not tainted
------------------------------------------------------
syz-executor419/5074 is trying to acquire lock:
ffff888023dc4d20 (team->team_lock_key){+.+.}-{3:3}, at: team_del_slave+0x32/0x1d0 drivers/net/team/team.c:1988

but task is already holding lock:
ffff88802a210768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: nl80211_del_interface+0x11a/0x140 net/wireless/nl80211.c:4389

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rdev->wiphy.mtx){+.+.}-{3:3}:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
wiphy_lock include/net/cfg80211.h:5951 [inline]
ieee80211_open+0xe7/0x200 net/mac80211/iface.c:449
__dev_open+0x2d3/0x450 net/core/dev.c:1430
dev_open+0xae/0x1b0 net/core/dev.c:1466
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:2685 [inline]
do_setlink+0xe70/0x41f0 net/core/rtnetlink.c:2891
rtnl_setlink+0x40d/0x5a0 net/core/rtnetlink.c:3185
rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6595
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

-> #0 (team->team_lock_key){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
team_del_slave+0x32/0x1d0 drivers/net/team/team.c:1988
team_device_event+0x200/0x5b0 drivers/net/team/team.c:3029
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]
unregister_netdevice_many_notify+0xd96/0x16d0 net/core/dev.c:11096
unregister_netdevice_many net/core/dev.c:11154 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11033
unregister_netdevice include/linux/netdevice.h:3115 [inline]
_cfg80211_unregister_wdev+0x162/0x560 net/wireless/core.c:1206
ieee80211_if_remove+0x25d/0x3a0 net/mac80211/iface.c:2242
ieee80211_del_iface+0x19/0x30 net/mac80211/cfg.c:202
rdev_del_virtual_intf net/wireless/rdev-ops.h:62 [inline]
cfg80211_remove_virtual_intf+0x230/0x3f0 net/wireless/util.c:2847
genl_family_rcv_msg_doit net/netlink/genetlink.c:1113 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1193 [inline]
genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1208
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1217
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

other info that might help us debug this:

Possible unsafe locking scenario:

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

*** DEADLOCK ***

3 locks held by syz-executor419/5074:
#0: ffffffff8f3f1a30 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1216
#1: ffffffff8f38ce88 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x5f/0x8b0 net/wireless/nl80211.c:16401
#2: ffff88802a210768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: nl80211_del_interface+0x11a/0x140 net/wireless/nl80211.c:4389

stack backtrace:
CPU: 1 PID: 5074 Comm: syz-executor419 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
team_del_slave+0x32/0x1d0 drivers/net/team/team.c:1988
team_device_event+0x200/0x5b0 drivers/net/team/team.c:3029
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]
unregister_netdevice_many_notify+0xd96/0x16d0 net/core/dev.c:11096
unregister_netdevice_many net/core/dev.c:11154 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11033
unregister_netdevice include/linux/netdevice.h:3115 [inline]
_cfg80211_unregister_wdev+0x162/0x560 net/wireless/core.c:1206
ieee80211_if_remove+0x25d/0x3a0 net/mac80211/iface.c:2242
ieee80211_del_iface+0x19/0x30 net/mac80211/cfg.c:202
rdev_del_virtual_intf net/wireless/rdev-ops.h:62 [inline]
cfg80211_remove_virtual_intf+0x230/0x3f0 net/wireless/util.c:2847
genl_family_rcv_msg_doit net/netlink/genetlink.c:1113 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1193 [inline]
genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1208
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1217
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f963cb981a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 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:00007ffdde1419a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f963cbe53f6 RCX: 00007f963cb981a9
RDX: 0000000000000000 RSI: 0000000020000400 RDI: 0000000000000004
RBP: 00007f963cc17440 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000031
R13: 0000000000000003 R14: 0000000000050012 R15: 00007ffdde141a02
</TASK>
team0: Port device wlan0 removed


---
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[Hillf Danton]

On Fri, 26 Apr 2024 04:59:32 -0700

ASSERT_RTNL();

ASSERT_RTNL();
lockdep_assert_wiphy(sdata->local->hw.wiphy);

Given ASSERT_RTNL() on both sides, difficult to understand the
deadlock reported.