Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning: ------------[ cut here ]------------ lockdep bfs error:-1 WARNING: kernel/locking/lockdep.c:2059 at print_bfs_bug+0x24/0x40 kernel/locking/lockdep.c:2059, CPU#1: kworker/u8:9/1112 Modules linked in: CPU: 1 UID: 0 PID: 1112 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_unbound flush_to_ldisc RIP: 0010:print_bfs_bug+0x26/0x40 kernel/locking/lockdep.c:2059 Code: 90 90 90 90 55 53 89 fb e8 37 44 35 03 89 c5 e8 20 ff ff ff 85 ed 74 17 83 fb ff 0f 84 e8 6d 3c ff 48 8d 3d fc 93 40 0f 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffffc90000a08368 EFLAGS: 00010082 RAX: 000000000000003b RBX: 00000000ffffffff RCX: 0000000000000000 RDX: 000000000000003b RSI: 00000000ffffffff RDI: ffffffff91261ab0 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000506 R11: fffffffffffe53a8 R12: ffffc90000a083e0 R13: ffff888026f3d850 R14: ffffc90000a08420 R15: ffff888026f3ca80 FS: 0000000000000000(0000) GS:ffff888123eda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff823ded158 CR3: 0000000075f0f000 CR4: 00000000003526f0 Call Trace: check_irq_usage+0x332/0x810 kernel/locking/lockdep.c:2816 check_prev_add+0xfe/0xe60 kernel/locking/lockdep.c:3169 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158 class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline] pcpu_alloc+0x1d4/0x350 lib/debugobjects.c:281 alloc_object lib/debugobjects.c:475 [inline] lookup_object_or_alloc.part.0+0xc7/0x4f0 lib/debugobjects.c:702 lookup_object_or_alloc lib/debugobjects.c:682 [inline] debug_object_activate+0x2fd/0x4b0 lib/debugobjects.c:875 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common.constprop.0+0x35/0x9b0 kernel/rcu/tree.c:3144 xa_node_free lib/xarray.c:260 [inline] xas_delete_node lib/xarray.c:503 [inline] update_node lib/xarray.c:767 [inline] xas_store+0xccb/0x1a30 lib/xarray.c:852 __xa_erase+0xb6/0x150 lib/xarray.c:1649 xa_erase+0x24/0x40 lib/xarray.c:1670 hsr_forget_seq_block net/hsr/hsr_framereg.c:319 [inline] hsr_get_seq_block+0x3f4/0x510 net/hsr/hsr_framereg.c:339 hsr_check_duplicate.isra.0+0x7f/0x120 net/hsr/hsr_framereg.c:601 hsr_forward_do net/hsr/hsr_forward.c:550 [inline] hsr_forward_skb+0xbb7/0x28d0 net/hsr/hsr_forward.c:743 send_hsr_supervision_frame+0x696/0xbc0 net/hsr/hsr_device.c:364 hsr_announce+0x169/0x3e0 net/hsr/hsr_device.c:421 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers+0x757/0xb00 kernel/time/timer.c:2374 __run_timer_base kernel/time/timer.c:2386 [inline] __run_timer_base kernel/time/timer.c:2378 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2395 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:console_flush_one_record+0xac3/0xe50 kernel/printk/printk.c:3270 Code: 00 e8 71 25 2a 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 bf d1 21 00 48 85 ed 0f 85 d7 01 00 00 e8 11 d7 21 00 fb 4c 89 e8 <48> c1 e8 03 42 80 3c 38 00 0f 85 64 03 00 00 48 8b 0c 24 48 8b 6b RSP: 0018:ffffc900057c7660 EFLAGS: 00000293 RAX: ffffffff8f9ace58 RBX: ffffffff8f9ace00 RCX: ffffffff81e88ac1 RDX: ffff888026f3ca80 RSI: ffffffff81e88acf RDI: ffff888026f3ca80 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000028b5 R13: ffffffff8f9ace58 R14: ffffc900057c76e0 R15: dffffc0000000000 console_flush_all kernel/printk/printk.c:3343 [inline] __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0x103/0x260 kernel/printk/printk.c:3413 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479 _printk+0xcf/0x110 kernel/printk/printk.c:2504 bt_err+0xec/0x122 net/bluetooth/lib.c:293 h4_recv+0x152/0x1d0 drivers/bluetooth/hci_h4.c:119 hci_uart_tty_receive+0x254/0x750 drivers/bluetooth/hci_ldisc.c:660 tty_ldisc_receive_buf+0x15a/0x1a0 drivers/tty/tty_buffer.c:398 tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:452 [inline] flush_to_ldisc+0x26b/0x730 drivers/tty/tty_buffer.c:502 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 55 push %rbp 5: 53 push %rbx 6: 89 fb mov %edi,%ebx 8: e8 37 44 35 03 call 0x3354444 d: 89 c5 mov %eax,%ebp f: e8 20 ff ff ff call 0xffffff34 14: 85 ed test %ebp,%ebp 16: 74 17 je 0x2f 18: 83 fb ff cmp $0xffffffff,%ebx 1b: 0f 84 e8 6d 3c ff je 0xff3c6e09 21: 48 8d 3d fc 93 40 0f lea 0xf4093fc(%rip),%rdi # 0xf409424 28: 89 de mov %ebx,%esi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 5b pop %rbx 30: 5d pop %rbp 31: c3 ret 32: cc int3 33: cc int3 34: cc int3 35: cc int3 36: 66 data16 37: 66 data16 38: 2e cs 39: 0f .byte 0xf 3a: 1f (bad) 3b: 84 00 test %al,(%rax) 3d: 00 00 add %al,(%rax)