====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.2967/12886 is trying to acquire lock: ffff88805200c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88805200c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4148 [inline] ffff88805200c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{3:3}, at: __dev_queue_xmit+0x22b7/0x3b50 net/core/dev.c:4691 but task is already holding lock: ffff888026b99108 (&local->handle_wake_tx_queue_lock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888026b99108 (&local->handle_wake_tx_queue_lock){+.-.}-{3:3}, at: ieee80211_handle_wake_tx_queue+0x84/0x2a0 net/mac80211/util.c:310 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&local->handle_wake_tx_queue_lock){+.-.}-{3:3}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] ieee80211_handle_wake_tx_queue+0x84/0x2a0 net/mac80211/util.c:310 drv_wake_tx_queue net/mac80211/driver-ops.h:1394 [inline] schedule_and_wake_txq net/mac80211/driver-ops.h:1401 [inline] ieee80211_queue_skb+0x1a31/0x21c0 net/mac80211/tx.c:1656 ieee80211_tx+0x297/0x420 net/mac80211/tx.c:1959 __ieee80211_subif_start_xmit+0xccf/0x1610 net/mac80211/tx.c:4333 ieee80211_subif_start_xmit+0xe0/0x510 net/mac80211/tx.c:4529 __netdev_start_xmit include/linux/netdevice.h:5222 [inline] netdev_start_xmit include/linux/netdevice.h:5231 [inline] xmit_one net/core/dev.c:3839 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3855 __dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4725 neigh_output include/net/neighbour.h:547 [inline] ip6_finish_output2+0x11fe/0x16a0 net/ipv6/ip6_output.c:141 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318 mld_sendpack+0x800/0xd80 net/ipv6/mcast.c:1860 mld_send_cr net/ipv6/mcast.c:2159 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2698 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 (_xmit_ETHER#2){+.-.}-{3:3}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4659 [inline] sch_direct_xmit+0x153/0x4b0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:4114 [inline] __dev_queue_xmit+0x1857/0x3b50 net/core/dev.c:4691 lapb_data_transmit+0x90/0xb0 net/lapb/lapb_iface.c:447 lapb_transmit_buffer+0x163/0x200 net/lapb/lapb_out.c:149 lapb_establish_data_link+0x89/0xe0 net/lapb/lapb_out.c:-1 lapb_device_event+0x4e1/0x670 net/lapb/lapb_iface.c:-1 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9617 dev_change_flags+0x130/0x260 net/core/dev_api.c:68 devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1199 inet_ioctl+0x3c0/0x4c0 net/ipv4/af_inet.c:1001 sock_do_ioctl+0xd9/0x300 net/socket.c:1238 sock_ioctl+0x576/0x790 net/socket.c:1359 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:4148 [inline] __dev_queue_xmit+0x22b7/0x3b50 net/core/dev.c:4691 dev_queue_xmit include/linux/netdevice.h:3361 [inline] __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline] __netlink_deliver_tap+0x5ad/0x850 net/netlink/af_netlink.c:325 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1262 [inline] netlink_sendskb+0x68/0x140 net/netlink/af_netlink.c:1271 netlink_unicast+0x397/0x9e0 net/netlink/af_netlink.c:1361 nlmsg_unicast include/net/netlink.h:1198 [inline] genlmsg_unicast include/net/genetlink.h:553 [inline] hwsim_unicast_netgroup+0x1be/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:1429 mac80211_hwsim_tx_frame_nl+0x895/0xc90 drivers/net/wireless/virtual/mac80211_hwsim.c:1609 drv_tx net/mac80211/driver-ops.h:38 [inline] wake_tx_push_queue net/mac80211/util.c:298 [inline] ieee80211_handle_wake_tx_queue+0x18e/0x2a0 net/mac80211/util.c:315 drv_wake_tx_queue net/mac80211/driver-ops.h:1394 [inline] schedule_and_wake_txq net/mac80211/driver-ops.h:1401 [inline] ieee80211_queue_skb+0x1a31/0x21c0 net/mac80211/tx.c:1656 ieee80211_tx+0x297/0x420 net/mac80211/tx.c:1959 __ieee80211_subif_start_xmit+0xccf/0x1610 net/mac80211/tx.c:4333 ieee80211_subif_start_xmit+0xe0/0x510 net/mac80211/tx.c:4529 __netdev_start_xmit include/linux/netdevice.h:5222 [inline] netdev_start_xmit include/linux/netdevice.h:5231 [inline] xmit_one net/core/dev.c:3839 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3855 __dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4725 dev_queue_xmit include/linux/netdevice.h:3361 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2478 [inline] bpf_clone_redirect+0x272/0x3d0 net/core/filter.c:2448 bpf_prog_c6f54bbad6dab1ee+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] bpf_test_run+0x318/0x7b0 net/bpf/test_run.c:434 bpf_prog_test_run_skb+0xb30/0x1560 net/bpf/test_run.c:1099 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4590 __sys_bpf+0x581/0x870 kernel/bpf/syscall.c:6047 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline] __se_sys_bpf kernel/bpf/syscall.c:6137 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: dev->qdisc_tx_busylock ?: &qdisc_tx_busylock --> _xmit_ETHER#2 --> &local->handle_wake_tx_queue_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&local->handle_wake_tx_queue_lock); lock(_xmit_ETHER#2); lock(&local->handle_wake_tx_queue_lock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** 8 locks held by syz.2.2967/12886: #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: bpf_test_timer_enter+0x1a/0x140 net/bpf/test_run.c:40 #1: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #1: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline] #1: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50 net/core/dev.c:4650 #2: ffff888031a41158 (_xmit_ETHER#2){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffff888031a41158 (_xmit_ETHER#2){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4659 [inline] #2: ffff888031a41158 (_xmit_ETHER#2){+.-.}-{3:3}, at: __dev_queue_xmit+0x1676/0x3b50 net/core/dev.c:4721 #3: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: __ieee80211_subif_start_xmit+0x2be/0x1610 net/mac80211/tx.c:4282 #4: ffff888026b99108 (&local->handle_wake_tx_queue_lock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff888026b99108 (&local->handle_wake_tx_queue_lock){+.-.}-{3:3}, at: ieee80211_handle_wake_tx_queue+0x84/0x2a0 net/mac80211/util.c:310 #5: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #5: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #5: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: hwsim_unicast_netgroup+0x2b/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:1426 #6: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #6: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #6: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: netlink_deliver_tap+0x2e/0x1b0 net/netlink/af_netlink.c:335 #7: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline] #7: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50 net/core/dev.c:4650 stack backtrace: CPU: 1 UID: 0 PID: 12886 Comm: syz.2.2967 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:4148 [inline] __dev_queue_xmit+0x22b7/0x3b50 net/core/dev.c:4691 dev_queue_xmit include/linux/netdevice.h:3361 [inline] __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline] __netlink_deliver_tap+0x5ad/0x850 net/netlink/af_netlink.c:325 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1262 [inline] netlink_sendskb+0x68/0x140 net/netlink/af_netlink.c:1271 netlink_unicast+0x397/0x9e0 net/netlink/af_netlink.c:1361 nlmsg_unicast include/net/netlink.h:1198 [inline] genlmsg_unicast include/net/genetlink.h:553 [inline] hwsim_unicast_netgroup+0x1be/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:1429 mac80211_hwsim_tx_frame_nl+0x895/0xc90 drivers/net/wireless/virtual/mac80211_hwsim.c:1609 drv_tx net/mac80211/driver-ops.h:38 [inline] wake_tx_push_queue net/mac80211/util.c:298 [inline] ieee80211_handle_wake_tx_queue+0x18e/0x2a0 net/mac80211/util.c:315 drv_wake_tx_queue net/mac80211/driver-ops.h:1394 [inline] schedule_and_wake_txq net/mac80211/driver-ops.h:1401 [inline] ieee80211_queue_skb+0x1a31/0x21c0 net/mac80211/tx.c:1656 ieee80211_tx+0x297/0x420 net/mac80211/tx.c:1959 __ieee80211_subif_start_xmit+0xccf/0x1610 net/mac80211/tx.c:4333 ieee80211_subif_start_xmit+0xe0/0x510 net/mac80211/tx.c:4529 __netdev_start_xmit include/linux/netdevice.h:5222 [inline] netdev_start_xmit include/linux/netdevice.h:5231 [inline] xmit_one net/core/dev.c:3839 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3855 __dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4725 dev_queue_xmit include/linux/netdevice.h:3361 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2478 [inline] bpf_clone_redirect+0x272/0x3d0 net/core/filter.c:2448 bpf_prog_c6f54bbad6dab1ee+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] bpf_test_run+0x318/0x7b0 net/bpf/test_run.c:434 bpf_prog_test_run_skb+0xb30/0x1560 net/bpf/test_run.c:1099 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4590 __sys_bpf+0x581/0x870 kernel/bpf/syscall.c:6047 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline] __se_sys_bpf kernel/bpf/syscall.c:6137 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f85bdd8ebe9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f85beb1e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f85bdfc6090 RCX: 00007f85bdd8ebe9 RDX: 0000000000000050 RSI: 0000200000001a00 RDI: 000000000000000a RBP: 00007f85bde11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f85bdfc6128 R14: 00007f85bdfc6090 R15: 00007ffe815e3828