syzbot

batman_adv: batadv0: Interface deactivated: batadv_slave_1
batman_adv: batadv0: Removing interface: batadv_slave_1
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0 Not tainted
------------------------------------------------------
kworker/u8:5/142 is trying to acquire lock:
ffff888027be4768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6092 [inline]
ffff888027be4768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_netdev_notifier_call+0x1b3/0x1430 net/wireless/core.c:1547

but task is already holding lock:
ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2751 [inline]
ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x5a1/0x2510 net/core/dev.c:11938

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&dev_instance_lock_key#3){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       netdev_lock include/linux/netdevice.h:2751 [inline]
       netdev_lock_ops include/net/netdev_lock.h:42 [inline]
       xsk_bind+0x2fd/0xfb0 net/xdp/xsk.c:1188
       __sys_bind_socket net/socket.c:1810 [inline]
       __sys_bind+0x1de/0x290 net/socket.c:1841
       __do_sys_bind net/socket.c:1846 [inline]
       __se_sys_bind net/socket.c:1844 [inline]
       __x64_sys_bind+0x7a/0x90 net/socket.c:1844
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&xs->mutex){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       xsk_diag_fill net/xdp/xsk_diag.c:113 [inline]
       xsk_diag_dump+0x5be/0x19d0 net/xdp/xsk_diag.c:166
       netlink_dump+0x678/0xeb0 net/netlink/af_netlink.c:2309
       __netlink_dump_start+0x5a2/0x790 net/netlink/af_netlink.c:2424
       netlink_dump_start include/linux/netlink.h:340 [inline]
       xsk_diag_handler_dump+0x1de/0x270 net/xdp/xsk_diag.c:193
       sock_diag_rcv_msg+0x3dc/0x5f0 net/core/sock_diag.c:-1
       netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg+0x221/0x270 net/socket.c:727
       sock_write_iter+0x2d9/0x3f0 net/socket.c:1131
       do_iter_readv_writev+0x71f/0x9d0 fs/read_write.c:-1
       vfs_writev+0x38d/0xbc0 fs/read_write.c:1055
       do_writev+0x1b8/0x360 fs/read_write.c:1101
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&net->xdp.lock){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       xsk_notifier+0x8b/0x230 net/xdp/xsk.c:1644
       notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2212 [inline]
       call_netdevice_notifiers net/core/dev.c:2226 [inline]
       unregister_netdevice_many_notify+0x1572/0x2510 net/core/dev.c:11971
       unregister_netdevice_many net/core/dev.c:12035 [inline]
       unregister_netdevice_queue+0x383/0x400 net/core/dev.c:11887
       unregister_netdevice include/linux/netdevice.h:3374 [inline]
       _cfg80211_unregister_wdev+0x163/0x590 net/wireless/core.c:1256
       ieee80211_if_remove+0x25d/0x320 net/mac80211/iface.c:2256
       ieee80211_del_iface+0x19/0x30 net/mac80211/cfg.c:224
       rdev_del_virtual_intf net/wireless/rdev-ops.h:62 [inline]
       cfg80211_remove_virtual_intf+0x23f/0x410 net/wireless/util.c:2871
       genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
       genl_rcv_msg+0xb38/0xf00 net/netlink/genetlink.c:1210
       netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
       netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
       netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
       netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg+0x221/0x270 net/socket.c:727
       ____sys_sendmsg+0x523/0x860 net/socket.c:2566
       ___sys_sendmsg net/socket.c:2620 [inline]
       __sys_sendmsg+0x271/0x360 net/socket.c:2652
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&rdev->wiphy.mtx){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       class_wiphy_constructor include/net/cfg80211.h:6092 [inline]
       cfg80211_netdev_notifier_call+0x1b3/0x1430 net/wireless/core.c:1547
       notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2212 [inline]
       call_netdevice_notifiers net/core/dev.c:2226 [inline]
       __dev_close_many+0x15d/0x760 net/core/dev.c:1671
       dev_close_many+0x250/0x4c0 net/core/dev.c:1725
       unregister_netdevice_many_notify+0x628/0x2510 net/core/dev.c:11940
       unregister_netdevice_many net/core/dev.c:12035 [inline]
       default_device_exit_batch+0x7ff/0x880 net/core/dev.c:12527
       ops_exit_list net/core/net_namespace.c:177 [inline]
       cleanup_net+0x8af/0xd60 net/core/net_namespace.c:654
       process_one_work kernel/workqueue.c:3238 [inline]
       process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
       worker_thread+0x870/0xd50 kernel/workqueue.c:3400
       kthread+0x7b7/0x940 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &rdev->wiphy.mtx --> &xs->mutex --> &dev_instance_lock_key#3

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&dev_instance_lock_key#3);
                               lock(&xs->mutex);
                               lock(&dev_instance_lock_key#3);
  lock(&rdev->wiphy.mtx);

 *** DEADLOCK ***

5 locks held by kworker/u8:5/142:
 #0: ffff88801bef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801bef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90002e3fc60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90002e3fc60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffffffff900f0a90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x17c/0xd60 net/core/net_namespace.c:608
 #3: ffffffff900fd5c8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xde/0x880 net/core/dev.c:12513
 #4: ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2751 [inline]
 #4: ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 #4: ffff888035d0cd30 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x5a1/0x2510 net/core/dev.c:11938

stack backtrace:
CPU: 0 UID: 0 PID: 142 Comm: kworker/u8:5 Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
 class_wiphy_constructor include/net/cfg80211.h:6092 [inline]
 cfg80211_netdev_notifier_call+0x1b3/0x1430 net/wireless/core.c:1547
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2212 [inline]
 call_netdevice_notifiers net/core/dev.c:2226 [inline]
 __dev_close_many+0x15d/0x760 net/core/dev.c:1671
 dev_close_many+0x250/0x4c0 net/core/dev.c:1725
 unregister_netdevice_many_notify+0x628/0x2510 net/core/dev.c:11940
 unregister_netdevice_many net/core/dev.c:12035 [inline]
 default_device_exit_batch+0x7ff/0x880 net/core/dev.c:12527
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x8af/0xd60 net/core/net_namespace.c:654
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd50 kernel/workqueue.c:3400
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode