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+0x7f/0xf0 kernel/locking/lockdep.c:2103, CPU#0: syz.0.9277/21007 Modules linked in: CPU: 0 UID: 0 PID: 21007 Comm: syz.0.9277 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:print_bfs_bug+0x81/0xf0 kernel/locking/lockdep.c:2103 Code: 09 48 c7 c7 db 4c 48 8e e8 5c 45 eb 09 65 ff 0d cd 41 a6 12 85 ed 74 17 83 fb ff 0f 84 20 15 3b ff 48 8d 3d 01 b6 61 0f 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc 90 e8 cd e0 40 03 85 c0 74 1d RSP: 0018:ffffc90024437248 EFLAGS: 00010082 RAX: 000000000000003b RBX: 00000000ffffffff RCX: 0000000000000000 RDX: 000000000000003b RSI: 00000000ffffffff RDI: ffffffff91489b20 RBP: 0000000000000001 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000001 R12: ffffc900244372c0 R13: ffff888025e30c28 R14: ffffc90024437300 R15: ffff888025e30c00 FS: 00007f7a0f3c76c0(0000) GS:ffff8880d5b52000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd001c70050 CR3: 0000000037aca000 CR4: 0000000000352ef0 Call Trace: check_irq_usage+0x32b/0x8b0 kernel/locking/lockdep.c:2860 check_prev_add+0xfe/0xe60 kernel/locking/lockdep.c:3213 check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 seqcount_lockdep_reader_access include/linux/seqlock.h:73 [inline] ktime_expiry_to_cycles+0x9b/0x2c0 kernel/time/timekeeping.c:941 clockevent_set_next_coupled kernel/time/clockevents.c:314 [inline] clockevents_program_event+0x1bf/0x820 kernel/time/clockevents.c:360 tick_program_event+0xa9/0x140 kernel/time/tick-oneshot.c:48 hrtimer_rearm_event kernel/time/hrtimer.c:710 [inline] hrtimer_rearm kernel/time/hrtimer.c:2176 [inline] __hrtimer_rearm_deferred+0x234/0x7b0 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+0x5f3/0xa10 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:preempt_schedule_irq+0x49/0x90 kernel/sched/core.c:7606 Code: 00 00 00 fc ff df 48 89 eb 48 c1 eb 03 48 01 d3 f6 c4 02 75 47 bf 01 00 00 00 e8 12 ad 03 f6 e8 8d 22 41 f6 fb bf 01 00 00 00 d2 8f ff ff 9c 58 fa f6 c4 02 75 1e bf 01 00 00 00 e8 00 4d 03 RSP: 0018:ffffc900244377c8 EFLAGS: 00000202 RAX: 000000000000078f RBX: ffffed1004bc6000 RCX: 0000000000000040 RDX: 0000000000000001 RSI: ffffffff8e38ded9 RDI: 0000000000000001 RBP: ffff888025e30000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa10 kernel/entry/common.c:167 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679 RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5947 Code: 05 0f 8e a5 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 1e 03 5e 0f 0f 82 c9 02 00 00 8b 35 be 34 5e 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 ad 8d a5 12 0f 85 09 03 00 00 48 83 c4 RSP: 0018:ffffc900244378d8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8e367a38 RDI: ffffffff8c623880 RBP: ffff88802c837140 R08: 000000000020f338 R09: ffffffff976e23a8 R10: 0000000000000200 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 touch_wq_lockdep_map+0xad/0x1c0 kernel/workqueue.c:4111 __flush_workqueue+0x131/0x1200 kernel/workqueue.c:4153 drain_workqueue+0x175/0x3b0 kernel/workqueue.c:4317 destroy_workqueue+0xc3/0xa30 kernel/workqueue.c:6155 ceph_osdc_stop+0x83/0x4f0 net/ceph/osd_client.c:5276 ceph_destroy_client+0x74/0x160 net/ceph/ceph_common.c:768 destroy_fs_client+0x1e4/0x3b0 fs/ceph/super.c:910 ceph_kill_sb+0x2ec/0x9d0 fs/ceph/super.c:1612 deactivate_locked_super+0xbd/0x140 fs/super.c:589 ceph_get_tree+0x1534/0x1fd0 fs/ceph/super.c:1380 vfs_get_tree+0x92/0x320 fs/super.c:1933 vfs_cmd_create+0xd7/0x2a0 fs/fsopen.c:231 vfs_fsconfig_locked fs/fsopen.c:295 [inline] __do_sys_fsconfig+0x55a/0xcb0 fs/fsopen.c:463 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7a0e59e159 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:00007f7a0f3c7028 EFLAGS: 00000246 ORIG_RAX: 00000000000001af RAX: ffffffffffffffda RBX: 00007f7a0e825fa0 RCX: 00007f7a0e59e159 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003 RBP: 00007f7a0e63506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7a0e826038 R14: 00007f7a0e825fa0 R15: 00007ffdd91369f8 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 48 c7 c7 db 4c 48 8e mov $0xffffffff8e484cdb,%rdi 7: e8 5c 45 eb 09 call 0x9eb4568 c: 65 ff 0d cd 41 a6 12 decl %gs:0x12a641cd(%rip) # 0x12a641e0 13: 85 ed test %ebp,%ebp 15: 74 17 je 0x2e 17: 83 fb ff cmp $0xffffffff,%ebx 1a: 0f 84 20 15 3b ff je 0xff3b1540 20: 48 8d 3d 01 b6 61 0f lea 0xf61b601(%rip),%rdi # 0xf61b628 27: 89 de mov %ebx,%esi * 29: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2e: 5b pop %rbx 2f: 5d pop %rbp 30: c3 ret 31: cc int3 32: cc int3 33: cc int3 34: cc int3 35: 90 nop 36: e8 cd e0 40 03 call 0x340e108 3b: 85 c0 test %eax,%eax 3d: 74 1d je 0x5c