====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.6.2648/16635 is trying to acquire lock: ffff8880b86241a8 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] ffff8880b86241a8 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: tasklet_lock_callback kernel/softirq.c:881 [inline] ffff8880b86241a8 (tasklet_sync_callback.cb_lock){+...}-{3:3}, at: tasklet_action_common+0xc5/0x600 kernel/softirq.c:931 but task is already holding lock: ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:620 [inline] ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xab/0x310 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+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:45 [inline] class_spinlock_irqsave_constructor include/linux/spinlock.h:620 [inline] input_inject_event+0xab/0x310 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:1118 [inline] kbd_bh+0x1b4/0x2c0 drivers/tty/vt/keyboard.c:1297 tasklet_action_common+0x31c/0x600 kernel/softirq.c:942 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1155 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (tasklet_sync_callback.cb_lock){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:45 [inline] tasklet_lock_callback kernel/softirq.c:881 [inline] tasklet_action_common+0xc5/0x600 kernel/softirq.c:931 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x1ad/0x7a0 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [inline] hidp_send_message+0xb5/0x230 net/bluetooth/hidp/core.c:108 hidp_send_intr_message net/bluetooth/hidp/core.c:140 [inline] hidp_input_event+0x2a4/0x380 net/bluetooth/hidp/core.c:172 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1fa/0x310 drivers/input/input.c:424 led_trigger_set+0x39e/0x940 drivers/leds/led-triggers.c:197 led_classdev_unregister+0xa8/0x270 drivers/leds/led-class.c:622 input_leds_disconnect+0x96/0x140 drivers/input/input-leds.c:184 __input_unregister_device+0x356/0x650 drivers/input/input.c:2206 input_unregister_device+0x9b/0x100 drivers/input/input.c:2438 hidp_session_dev_del net/bluetooth/hidp/core.c:886 [inline] hidp_session_probe+0x775/0x8b0 net/bluetooth/hidp/core.c:1171 l2cap_register_user+0xbd/0x1d0 net/bluetooth/l2cap_core.c:1754 hidp_connection_add+0x1582/0x1a10 net/bluetooth/hidp/core.c:1421 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:78 [inline] hidp_sock_ioctl+0x403/0x650 net/bluetooth/hidp/sock.c:125 sock_do_ioctl+0x101/0x320 net/socket.c:1340 sock_ioctl+0x57d/0x7f0 net/socket.c:1461 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+0x174/0x580 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.6.2648/16635: #0: ffff88823bf78370 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_register_user+0x34/0x1d0 net/bluetooth/l2cap_core.c:1741 #1: ffffffff8f75a7e0 (hidp_session_sem){++++}-{4:4}, at: hidp_session_probe+0x98/0x8b0 net/bluetooth/hidp/core.c:1139 #2: ffffffff8f01e3f8 (input_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #2: ffffffff8f01e3f8 (input_mutex){+.+.}-{4:4}, at: __input_unregister_device+0x2d8/0x650 drivers/input/input.c:2204 #3: ffff88803e28e788 (&led_cdev->trigger_lock){+.+.}-{4:4}, at: led_classdev_unregister+0x75/0x270 drivers/leds/led-class.c:620 #4: ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #4: ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:620 [inline] #4: ffff888062bec270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xab/0x310 drivers/input/input.c:419 #5: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #5: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #5: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #5: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 #6: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #6: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline] #6: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: input_inject_event+0xb7/0x310 drivers/input/input.c:420 #7: ffffffff8e1c3780 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 stack backtrace: CPU: 0 UID: 0 PID: 16635 Comm: syz.6.2648 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2045 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:45 [inline] tasklet_lock_callback kernel/softirq.c:881 [inline] tasklet_action_common+0xc5/0x600 kernel/softirq.c:931 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x1ad/0x7a0 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [inline] hidp_send_message+0xb5/0x230 net/bluetooth/hidp/core.c:108 hidp_send_intr_message net/bluetooth/hidp/core.c:140 [inline] hidp_input_event+0x2a4/0x380 net/bluetooth/hidp/core.c:172 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1fa/0x310 drivers/input/input.c:424 led_trigger_set+0x39e/0x940 drivers/leds/led-triggers.c:197 led_classdev_unregister+0xa8/0x270 drivers/leds/led-class.c:622 input_leds_disconnect+0x96/0x140 drivers/input/input-leds.c:184 __input_unregister_device+0x356/0x650 drivers/input/input.c:2206 input_unregister_device+0x9b/0x100 drivers/input/input.c:2438 hidp_session_dev_del net/bluetooth/hidp/core.c:886 [inline] hidp_session_probe+0x775/0x8b0 net/bluetooth/hidp/core.c:1171 l2cap_register_user+0xbd/0x1d0 net/bluetooth/l2cap_core.c:1754 hidp_connection_add+0x1582/0x1a10 net/bluetooth/hidp/core.c:1421 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:78 [inline] hidp_sock_ioctl+0x403/0x650 net/bluetooth/hidp/sock.c:125 sock_do_ioctl+0x101/0x320 net/socket.c:1340 sock_ioctl+0x57d/0x7f0 net/socket.c:1461 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+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f82fad3de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f82f8f54028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f82fafc6180 RCX: 00007f82fad3de59 RDX: 0000200000000340 RSI: 00000000400448c8 RDI: 0000000000000009 RBP: 00007f82fadd3e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f82fafc6218 R14: 00007f82fafc6180 R15: 00007ffffd05b1a8