====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.5.14942/11852 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+0xc5/0x610 kernel/softirq.c:931 but task is already holding lock: ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline] ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xa4/0x320 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:619 [inline] input_inject_event+0xa4/0x320 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/0x610 kernel/softirq.c:942 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1155 smpboot_thread_fn+0x541/0xa50 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+0x15a5/0x2d10 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+0xc5/0x610 kernel/softirq.c:931 handle_softirqs+0x1de/0x6d0 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+0x1aa/0x7d0 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1382 [inline] hidp_send_message+0xb5/0x230 net/bluetooth/hidp/core.c:111 hidp_send_intr_message net/bluetooth/hidp/core.c:143 [inline] hidp_input_event+0x2a4/0x380 net/bluetooth/hidp/core.c:175 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1d7/0x320 drivers/input/input.c:424 kbd_led_trigger_activate+0xbc/0x100 drivers/tty/vt/keyboard.c:1074 led_trigger_set+0x53b/0x960 drivers/leds/led-triggers.c:220 led_match_default_trigger drivers/leds/led-triggers.c:277 [inline] led_trigger_set_default+0x266/0x2a0 drivers/leds/led-triggers.c:300 led_classdev_register_ext+0x787/0x9c0 drivers/leds/led-class.c:581 led_classdev_register include/linux/leds.h:274 [inline] input_leds_connect+0x517/0x790 drivers/input/input-leds.c:145 input_attach_handler drivers/input/input.c:1011 [inline] input_register_device+0xce0/0x1140 drivers/input/input.c:2395 hidp_session_dev_add net/bluetooth/hidp/core.c:874 [inline] hidp_session_probe+0x1a5/0x8a0 net/bluetooth/hidp/core.c:1152 l2cap_register_user+0xc2/0x1d0 net/bluetooth/l2cap_core.c:1727 hidp_connection_add+0x158b/0x1a20 net/bluetooth/hidp/core.c:1424 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:81 [inline] hidp_sock_ioctl+0x403/0x650 net/bluetooth/hidp/sock.c:128 sock_do_ioctl+0x101/0x320 net/socket.c:1328 sock_ioctl+0x5c9/0x7f0 net/socket.c:1449 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 *** 10 locks held by syz.5.14942/11852: #0: ffff88802b8df370 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_register_user+0x35/0x1d0 net/bluetooth/l2cap_core.c:1714 #1: ffffffff8f75a980 (hidp_session_sem){++++}-{4:4}, at: hidp_session_probe+0x98/0x8a0 net/bluetooth/hidp/core.c:1142 #2: ffffffff8f020058 (input_mutex){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline] #2: ffffffff8f020058 (input_mutex){+.+.}-{4:4}, at: input_register_device+0xa56/0x1140 drivers/input/input.c:2391 #3: ffff88804cc7e860 (&led_cdev->led_access){+.+.}-{4:4}, at: led_classdev_register_ext+0x484/0x9c0 drivers/leds/led-class.c:539 #4: ffffffff8e9d8a60 (triggers_list_lock){++++}-{4:4}, at: led_trigger_set_default+0x77/0x2a0 drivers/leds/led-triggers.c:297 #5: ffff88804cc7e788 (&led_cdev->trigger_lock){+.+.}-{4:4}, at: led_trigger_set_default+0x87/0x2a0 drivers/leds/led-triggers.c:298 #6: ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #6: ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline] #6: ffff888038d08270 (&dev->event_lock#2){+.+.}-{3:3}, at: input_inject_event+0xa4/0x320 drivers/input/input.c:419 #7: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #7: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #7: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #7: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 #8: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #8: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #8: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline] #8: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: input_inject_event+0xb0/0x320 drivers/input/input.c:420 #9: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 stack backtrace: CPU: 0 UID: 0 PID: 11852 Comm: syz.5.14942 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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+0x15a5/0x2d10 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+0xc5/0x610 kernel/softirq.c:931 handle_softirqs+0x1de/0x6d0 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+0x1aa/0x7d0 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1382 [inline] hidp_send_message+0xb5/0x230 net/bluetooth/hidp/core.c:111 hidp_send_intr_message net/bluetooth/hidp/core.c:143 [inline] hidp_input_event+0x2a4/0x380 net/bluetooth/hidp/core.c:175 input_event_dispose+0x80/0x6b0 drivers/input/input.c:322 input_inject_event+0x1d7/0x320 drivers/input/input.c:424 kbd_led_trigger_activate+0xbc/0x100 drivers/tty/vt/keyboard.c:1074 led_trigger_set+0x53b/0x960 drivers/leds/led-triggers.c:220 led_match_default_trigger drivers/leds/led-triggers.c:277 [inline] led_trigger_set_default+0x266/0x2a0 drivers/leds/led-triggers.c:300 led_classdev_register_ext+0x787/0x9c0 drivers/leds/led-class.c:581 led_classdev_register include/linux/leds.h:274 [inline] input_leds_connect+0x517/0x790 drivers/input/input-leds.c:145 input_attach_handler drivers/input/input.c:1011 [inline] input_register_device+0xce0/0x1140 drivers/input/input.c:2395 hidp_session_dev_add net/bluetooth/hidp/core.c:874 [inline] hidp_session_probe+0x1a5/0x8a0 net/bluetooth/hidp/core.c:1152 l2cap_register_user+0xc2/0x1d0 net/bluetooth/l2cap_core.c:1727 hidp_connection_add+0x158b/0x1a20 net/bluetooth/hidp/core.c:1424 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:81 [inline] hidp_sock_ioctl+0x403/0x650 net/bluetooth/hidp/sock.c:128 sock_do_ioctl+0x101/0x320 net/socket.c:1328 sock_ioctl+0x5c9/0x7f0 net/socket.c:1449 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: 0033:0x7f1161c1ce59 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:00007f115fe76028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1161e95fa0 RCX: 00007f1161c1ce59 RDX: 00002000000000c0 RSI: 00000000400448c8 RDI: 0000000000000005 RBP: 00007f1161cb2d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1161e96038 R14: 00007f1161e95fa0 R15: 00007fffc56c9bd8