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.2.2796/20857 Modules linked in: CPU: 1 UID: 0 PID: 20857 Comm: syz.2.2796 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 e7 a2 37 03 89 c5 e8 c0 85 ff ff 85 ed 74 13 83 fb ff 74 16 48 8d 3d 10 e8 d9 0e 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc cc 48 c7 c7 3a c8 60 8e e8 d5 RSP: 0018:ffffc900036c64e8 EFLAGS: 00010046 RAX: 000000000000003b RBX: 00000000ffffffff RCX: e4f05b1a3b8c8c00 RDX: ffffc9000f092000 RSI: 00000000ffffffff RDI: ffffffff907d70c0 RBP: 0000000000000001 R08: ffffc900036c6267 R09: 1ffff920006d8c4c R10: dffffc0000000000 R11: fffff520006d8c4d R12: 0000000000000060 R13: ffffffff9444bac8 R14: ffffffff9738c0c8 R15: ffffffff9738c138 FS: 00007f1a5867b6c0(0000) GS:ffff888124dd1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f49f227feb3 CR3: 000000007a826000 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:2169 [inline] __hrtimer_rearm_deferred+0x36c/0x4b0 kernel/time/hrtimer.c:2189 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 f0 09 42 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 42 c5 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d c7 3f da RSP: 0018:ffffc900036c6950 EFLAGS: 00000296 RAX: e4f05b1a3b8c8c00 RBX: 0000000000000001 RCX: 8000000000000201 RDX: ffff88807a076998 RSI: ffffffff8e6fe025 RDI: ffffffff8c6d9c80 RBP: ffff88807a075dc0 R08: 0000000000000008 R09: ffffffff96c6dd80 R10: 000000004a6877ba R11: 00000000b70e9ec9 R12: ffff8880852a2170 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+0xdd6/0x4670 net/core/rtnetlink.c:3271 rtnl_group_changelink net/core/rtnetlink.c:3924 [inline] __rtnl_newlink net/core/rtnetlink.c:4090 [inline] rtnl_newlink+0x146f/0x1c30 net/core/rtnetlink.c:4220 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7137 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802 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: 0033:0x7f1a5779e159 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:00007f1a5867b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f1a57a26090 RCX: 00007f1a5779e159 RDX: 0000000000000000 RSI: 0000200000000100 RDI: 0000000000000008 RBP: 00007f1a5783503b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1a57a26128 R14: 00007f1a57a26090 R15: 00007ffcfed7e278 ---------------- 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 e7 a2 37 03 call 0x337a2f8 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 10 e8 d9 0e lea 0xed9e810(%rip),%rdi # 0xed9e838 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: cc int3 37: 48 c7 c7 3a c8 60 8e mov $0xffffffff8e60c83a,%rdi 3e: e8 .byte 0xe8 3f: d5 .byte 0xd5