====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.2585/14873 is trying to acquire lock: ffff8880b8924218 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffff8880b8924218 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: tasklet_lock_callback kernel/softirq.c:864 [inline] ffff8880b8924218 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: tasklet_action_common+0x130/0x650 kernel/softirq.c:914 but task is already holding lock: ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xa5/0x330 drivers/input/input.c:419 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&dev->event_lock#2){+.+.}-{3:3}: rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] input_inject_event+0xa5/0x330 drivers/input/input.c:419 led_trigger_event+0x13b/0x220 drivers/leds/led-triggers.c:420 kbd_propagate_led_state drivers/tty/vt/keyboard.c:1073 [inline] kbd_bh+0x1b4/0x2c0 drivers/tty/vt/keyboard.c:1262 tasklet_action_common+0x36b/0x650 kernel/softirq.c:925 handle_softirqs+0x226/0x6d0 kernel/softirq.c:622 run_ksoftirqd+0xac/0x210 kernel/softirq.c:1063 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 -> #0 (tasklet_sync_callback.cb_lock){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] tasklet_lock_callback kernel/softirq.c:864 [inline] tasklet_action_common+0x130/0x650 kernel/softirq.c:914 handle_softirqs+0x226/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x224/0x430 net/core/skbuff.c:674 alloc_skb include/linux/skbuff.h:1383 [inline] hidp_send_message+0xb6/0x210 net/bluetooth/hidp/core.c:111 hidp_send_intr_message net/bluetooth/hidp/core.c:143 [inline] hidp_input_event+0x290/0x340 net/bluetooth/hidp/core.c:175 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1d8/0x330 drivers/input/input.c:424 led_trigger_set+0x384/0x950 drivers/leds/led-triggers.c:197 led_classdev_unregister+0xa8/0x270 drivers/leds/led-class.c:604 input_leds_disconnect+0xba/0x180 drivers/input/input-leds.c:184 __input_unregister_device+0x3a3/0x640 drivers/input/input.c:2189 input_unregister_device+0x9b/0x100 drivers/input/input.c:2418 hidp_session_dev_del net/bluetooth/hidp/core.c:876 [inline] hidp_session_probe+0x764/0x8a0 net/bluetooth/hidp/core.c:1138 l2cap_register_user+0xf4/0x200 net/bluetooth/l2cap_core.c:1712 hidp_connection_add+0x158b/0x1a20 net/bluetooth/hidp/core.c:1378 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:81 [inline] hidp_sock_ioctl+0x36c/0x560 net/bluetooth/hidp/sock.c:128 sock_do_ioctl+0xdc/0x300 net/socket.c:1245 sock_ioctl+0x579/0x790 net/socket.c:1366 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&dev->event_lock#2); lock(tasklet_sync_callback.cb_lock); lock(&dev->event_lock#2); lock(tasklet_sync_callback.cb_lock); *** DEADLOCK *** 8 locks held by syz.4.2585/14873: #0: ffff8880327340b0 (&hdev->lock){+.+.}-{4:4}, at: l2cap_register_user+0x67/0x200 net/bluetooth/l2cap_core.c:1699 #1: ffffffff8ea30360 (hidp_session_sem){++++}-{4:4}, at: hidp_session_probe+0x99/0x8a0 net/bluetooth/hidp/core.c:1106 #2: ffffffff8e3171b8 (input_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #2: ffffffff8e3171b8 (input_mutex){+.+.}-{4:4}, at: __input_unregister_device+0x328/0x640 drivers/input/input.c:2187 #3: ffff88806a6b0788 (&led_cdev->trigger_lock){+.+.}-{4:4}, at: led_classdev_unregister+0x75/0x270 drivers/leds/led-class.c:602 #4: ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] #4: ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:585 [inline] #4: ffff88803d8fe270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xa5/0x330 drivers/input/input.c:419 #5: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #5: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #5: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #5: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1c1/0x3e0 kernel/locking/spinlock_rt.c:57 #6: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #6: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #6: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1195 [inline] #6: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: input_inject_event+0xb1/0x330 drivers/input/input.c:420 #7: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0xa1/0x530 kernel/softirq.c:163 stack backtrace: CPU: 1 UID: 0 PID: 14873 Comm: syz.4.2585 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] tasklet_lock_callback kernel/softirq.c:864 [inline] tasklet_action_common+0x130/0x650 kernel/softirq.c:914 handle_softirqs+0x226/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x224/0x430 net/core/skbuff.c:674 alloc_skb include/linux/skbuff.h:1383 [inline] hidp_send_message+0xb6/0x210 net/bluetooth/hidp/core.c:111 hidp_send_intr_message net/bluetooth/hidp/core.c:143 [inline] hidp_input_event+0x290/0x340 net/bluetooth/hidp/core.c:175 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1d8/0x330 drivers/input/input.c:424 led_trigger_set+0x384/0x950 drivers/leds/led-triggers.c:197 led_classdev_unregister+0xa8/0x270 drivers/leds/led-class.c:604 input_leds_disconnect+0xba/0x180 drivers/input/input-leds.c:184 __input_unregister_device+0x3a3/0x640 drivers/input/input.c:2189 input_unregister_device+0x9b/0x100 drivers/input/input.c:2418 hidp_session_dev_del net/bluetooth/hidp/core.c:876 [inline] hidp_session_probe+0x764/0x8a0 net/bluetooth/hidp/core.c:1138 l2cap_register_user+0xf4/0x200 net/bluetooth/l2cap_core.c:1712 hidp_connection_add+0x158b/0x1a20 net/bluetooth/hidp/core.c:1378 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:81 [inline] hidp_sock_ioctl+0x36c/0x560 net/bluetooth/hidp/sock.c:128 sock_do_ioctl+0xdc/0x300 net/socket.c:1245 sock_ioctl+0x579/0x790 net/socket.c:1366 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f27e298f749 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:00007f27e0bcd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f27e2be6090 RCX: 00007f27e298f749 RDX: 0000200000000280 RSI: 00000000400448c8 RDI: 0000000000000004 RBP: 00007f27e2a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f27e2be6128 R14: 00007f27e2be6090 R15: 00007ffe0972c9d8