Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning: ------------[ cut here ]------------ lockdep bfs error:-1 WARNING: kernel/locking/lockdep.c:2103 at print_bfs_bug+0x20/0x40 kernel/locking/lockdep.c:2103, CPU#1: syz.3.14253/7464 Modules linked in: CPU: 1 UID: 0 PID: 7464 Comm: syz.3.14253 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:print_bfs_bug+0x22/0x40 kernel/locking/lockdep.c:2103 Code: 90 90 90 90 90 90 90 90 55 53 89 fb e8 47 eb 37 03 89 c5 e8 c0 85 ff ff 85 ed 74 13 83 fb ff 74 16 48 8d 3d e0 f3 d9 0e 89 de <67> 48 0f b9 3a 5b 5d e9 02 8c 45 0a cc 48 c7 c7 a7 a0 5a 8e e8 45 RSP: 0018:ffffc90004f5e4c8 EFLAGS: 00010046 RAX: 000000000000003b RBX: 00000000ffffffff RCX: 874f505801d69d00 RDX: ffffc9000e38a000 RSI: 00000000ffffffff RDI: ffffffff907d8130 RBP: 0000000000000001 R08: ffffc90004f5e247 R09: 1ffff920009ebc48 R10: dffffc0000000000 R11: fffff520009ebc49 R12: 0000000000000040 R13: ffffffff943ed300 R14: ffffffff972353f8 R15: ffffffff97235e08 FS: 00007f667b3f66c0(0000) GS:ffff888124dcd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4686cdd023 CR3: 000000005e41a000 CR4: 00000000003526f0 Call Trace: check_irq_usage kernel/locking/lockdep.c:-1 [inline] check_prev_add kernel/locking/lockdep.c:3213 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x25ed/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73 ktime_get+0x45/0x220 kernel/time/timekeeping.c:1002 clockevents_program_event+0x290/0x630 kernel/time/clockevents.c:363 hrtimer_rearm kernel/time/hrtimer.c:2176 [inline] __hrtimer_rearm_deferred+0x36c/0x4b0 kernel/time/hrtimer.c:2196 hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:58 [inline] hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:67 [inline] irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:505 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:542 [inline] irqentry_exit+0x8d3/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947 Code: ff ff ff e8 50 e5 42 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 a2 00 f2 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 bf e9 45 0a cc 48 8d 3d 97 4b da RSP: 0018:ffffc90004f5e930 EFLAGS: 00000296 RAX: 874f505801d69d00 RBX: 0000000000000001 RCX: 8000000000000201 RDX: ffff88802797ab18 RSI: ffffffff8e69baf3 RDI: ffffffff8c6da080 RBP: ffff888027979f40 R08: 0000000000000008 R09: ffffffff96bbb540 R10: 000000002f4e82fd R11: 000000003f5302d9 R12: ffff888044124170 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:182 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:205 spin_lock_bh include/linux/spinlock.h:353 [inline] some_qdisc_is_busy net/sched/sch_generic.c:1352 [inline] dev_deactivate_many+0xade/0xda0 net/sched/sch_generic.c:1404 __dev_close_many+0x180/0x6e0 net/core/dev.c:1782 __dev_close net/core/dev.c:1811 [inline] __dev_change_flags+0x3f5/0x820 net/core/dev.c:9810 netif_change_flags+0x7c/0x1b0 net/core/dev.c:9877 do_setlink+0xdd6/0x47a0 net/core/rtnetlink.c:3284 rtnl_group_changelink net/core/rtnetlink.c:3946 [inline] __rtnl_newlink net/core/rtnetlink.c:4112 [inline] rtnl_newlink+0x147c/0x1c30 net/core/rtnetlink.c:4242 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7159 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2575 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2712 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2766 __sys_sendmsg net/socket.c:2798 [inline] __do_sys_sendmsg net/socket.c:2803 [inline] __se_sys_sendmsg net/socket.c:2801 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2801 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f667d19e159 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:00007f667b3f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f667d426090 RCX: 00007f667d19e159 RDX: 0000000000004004 RSI: 0000200000000200 RDI: 0000000000000005 RBP: 00007f667d23506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f667d426128 R14: 00007f667d426090 R15: 00007fffa56a6e98 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 90 nop 5: 90 nop 6: 90 nop 7: 90 nop 8: 55 push %rbp 9: 53 push %rbx a: 89 fb mov %edi,%ebx c: e8 47 eb 37 03 call 0x337eb58 11: 89 c5 mov %eax,%ebp 13: e8 c0 85 ff ff call 0xffff85d8 18: 85 ed test %ebp,%ebp 1a: 74 13 je 0x2f 1c: 83 fb ff cmp $0xffffffff,%ebx 1f: 74 16 je 0x37 21: 48 8d 3d e0 f3 d9 0e lea 0xed9f3e0(%rip),%rdi # 0xed9f408 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: e9 02 8c 45 0a jmp 0xa458c38 36: cc int3 37: 48 c7 c7 a7 a0 5a 8e mov $0xffffffff8e5aa0a7,%rdi 3e: e8 .byte 0xe8 3f: 45 rex.RB