Extracting prog: 6m47.814052162s
Minimizing prog: 36m38.544426876s
Simplifying prog options: 0s
Extracting C: 2m50.133109698s
Simplifying C: 19m26.374964806s
extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
single: failed to extract reproducer
single: executing 1 programs separately with timeout 1m40s
testing program (duration=1m40s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
single: failed to extract reproducer
single: executing 1 programs separately with timeout 6m0s
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program crashed: WARNING in print_bfs_bug
single: successfully extracted reproducer
found reproducer with 2 syscalls
minimizing guilty program
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mount
detailed listing:
executing program 0:
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(0x0, 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(0x0, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, 0x0, &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', 0x0, 0x8080, 0x0)
program did not crash
extracting C reproducer
testing compiled C program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
simplifying C reproducer
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: no output from test machine
a never seen crash title: no output from test machine, ignore
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing compiled C program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
program crashed: WARNING in print_bfs_bug
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program crashed: WARNING in print_bfs_bug
validation run: crashed=true
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program crashed: WARNING in print_bfs_bug
validation run: crashed=true
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mknod-mount
detailed listing:
executing program 0:
mknod(&(0x7f0000000080)='./bus\x00', 0xc000, 0x0)
mount(&(0x7f0000000000)=@nbd={'/dev/nbd', 0x0}, &(0x7f00000000c0)='./bus\x00', &(0x7f0000000040)='xfs\x00', 0x8080, 0x0)
program crashed: WARNING in print_bfs_bug
validation run: crashed=true
reproducing took 1h14m4.605435107s
repro crashed as (corrupted=false):
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+0x20/0x40 kernel/locking/lockdep.c:2059, CPU#0: syz.3.1743/16424
Modules linked in:
CPU: 0 UID: 0 PID: 16424 Comm: syz.3.1743 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:print_bfs_bug+0x22/0x40 kernel/locking/lockdep.c:2059
Code: 90 90 90 90 90 90 90 90 55 53 89 fb e8 a7 55 13 03 89 c5 e8 10 8a ff ff 85 ed 74 13 83 fb ff 74 16 48 8d 3d 60 29 95 0e 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc cc 48 c7 c7 d3 7f 1a 8e e8 c5
RSP: 0018:ffffc9000587f1b0 EFLAGS: 00010046
RAX: 000000000000003b RBX: 00000000ffffffff RCX: 9568d1c6705a5a00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff90377c40
RBP: 0000000000000001 R08: ffffc9000587ef27 R09: 1ffff92000b0fde4
R10: dffffc0000000000 R11: fffff52000b0fde5 R12: ffffffff96d283a8
R13: ffffffff93ee34e0 R14: ffff888059e7bd00 R15: 0000000000000041
FS: 0000555563d2b500(0000) GS:ffff888124ff7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c008c35000 CR3: 0000000075598000 CR4: 00000000003526f0
Call Trace:
check_irq_usage kernel/locking/lockdep.c:-1 [inline]
check_prev_add kernel/locking/lockdep.c:3169 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x2550/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73
ktime_get+0x45/0x220 kernel/time/timekeeping.c:958
clockevents_program_event+0x286/0x4b0 kernel/time/clockevents.c:360
hrtimer_rearm kernel/time/hrtimer.c:2037 [inline]
__hrtimer_rearm_deferred+0x29b/0x480 kernel/time/hrtimer.c:2057
hrtick_schedule_exit+0x1c7/0x2b0 kernel/sched/core.c:998
__schedule+0x1c5d/0x5590 kernel/sched/core.c:6974
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294
irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 e5 1a 19 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 81 97 a0 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 8e 7d 95
RSP: 0018:ffffc9000587f868 EFLAGS: 00000282
RAX: 9568d1c6705a5a00 RBX: 0000000000000246 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e29288d RDI: ffffffff8c29fee0
RBP: 0000000000000000 R08: 0000000000000008 R09: ffffffff9668c4c0
R10: 000000001afbcd9d R11: 000000006922f544 R12: 0000000000000000
R13: ffff888057aef948 R14: 0000000000000000 R15: 0000000000000001
touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3994
__flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:4036
drain_workqueue+0xd3/0x390 kernel/workqueue.c:4200
destroy_workqueue+0xbb/0xc60 kernel/workqueue.c:5970
xfs_destroy_mount_workqueues+0xd3/0x100 fs/xfs/xfs_super.c:654
xfs_fs_fill_super+0x682/0x1600 fs/xfs/xfs_super.c:1970
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a04d9c799
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:00007ffd0973d198 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5a05015fa0 RCX: 00007f5a04d9c799
RDX: 0000200000000040 RSI: 00002000000000c0 RDI: 0000200000000000
RBP: 00007f5a04e32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a05015fac R14: 00007f5a05015fa0 R15: 00007f5a05015fa0
----------------
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 a7 55 13 03 call 0x31355b8
11: 89 c5 mov %eax,%ebp
13: e8 10 8a ff ff call 0xffff8a28
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 60 29 95 0e lea 0xe952960(%rip),%rdi # 0xe952988
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 d3 7f 1a 8e mov $0xffffffff8e1a7fd3,%rdi
3e: e8 .byte 0xe8
3f: c5 .byte 0xc5
final repro crashed as (corrupted=false):
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+0x20/0x40 kernel/locking/lockdep.c:2059, CPU#0: syz.3.1743/16424
Modules linked in:
CPU: 0 UID: 0 PID: 16424 Comm: syz.3.1743 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:print_bfs_bug+0x22/0x40 kernel/locking/lockdep.c:2059
Code: 90 90 90 90 90 90 90 90 55 53 89 fb e8 a7 55 13 03 89 c5 e8 10 8a ff ff 85 ed 74 13 83 fb ff 74 16 48 8d 3d 60 29 95 0e 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc cc 48 c7 c7 d3 7f 1a 8e e8 c5
RSP: 0018:ffffc9000587f1b0 EFLAGS: 00010046
RAX: 000000000000003b RBX: 00000000ffffffff RCX: 9568d1c6705a5a00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff90377c40
RBP: 0000000000000001 R08: ffffc9000587ef27 R09: 1ffff92000b0fde4
R10: dffffc0000000000 R11: fffff52000b0fde5 R12: ffffffff96d283a8
R13: ffffffff93ee34e0 R14: ffff888059e7bd00 R15: 0000000000000041
FS: 0000555563d2b500(0000) GS:ffff888124ff7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c008c35000 CR3: 0000000075598000 CR4: 00000000003526f0
Call Trace:
check_irq_usage kernel/locking/lockdep.c:-1 [inline]
check_prev_add kernel/locking/lockdep.c:3169 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x2550/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73
ktime_get+0x45/0x220 kernel/time/timekeeping.c:958
clockevents_program_event+0x286/0x4b0 kernel/time/clockevents.c:360
hrtimer_rearm kernel/time/hrtimer.c:2037 [inline]
__hrtimer_rearm_deferred+0x29b/0x480 kernel/time/hrtimer.c:2057
hrtick_schedule_exit+0x1c7/0x2b0 kernel/sched/core.c:998
__schedule+0x1c5d/0x5590 kernel/sched/core.c:6974
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294
irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 e5 1a 19 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 81 97 a0 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 8e 7d 95
RSP: 0018:ffffc9000587f868 EFLAGS: 00000282
RAX: 9568d1c6705a5a00 RBX: 0000000000000246 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e29288d RDI: ffffffff8c29fee0
RBP: 0000000000000000 R08: 0000000000000008 R09: ffffffff9668c4c0
R10: 000000001afbcd9d R11: 000000006922f544 R12: 0000000000000000
R13: ffff888057aef948 R14: 0000000000000000 R15: 0000000000000001
touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3994
__flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:4036
drain_workqueue+0xd3/0x390 kernel/workqueue.c:4200
destroy_workqueue+0xbb/0xc60 kernel/workqueue.c:5970
xfs_destroy_mount_workqueues+0xd3/0x100 fs/xfs/xfs_super.c:654
xfs_fs_fill_super+0x682/0x1600 fs/xfs/xfs_super.c:1970
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a04d9c799
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:00007ffd0973d198 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5a05015fa0 RCX: 00007f5a04d9c799
RDX: 0000200000000040 RSI: 00002000000000c0 RDI: 0000200000000000
RBP: 00007f5a04e32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a05015fac R14: 00007f5a05015fa0 R15: 00007f5a05015fa0
----------------
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 a7 55 13 03 call 0x31355b8
11: 89 c5 mov %eax,%ebp
13: e8 10 8a ff ff call 0xffff8a28
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 60 29 95 0e lea 0xe952960(%rip),%rdi # 0xe952988
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 d3 7f 1a 8e mov $0xffffffff8e1a7fd3,%rdi
3e: e8 .byte 0xe8
3f: c5 .byte 0xc5