INFO: task syz-executor:5822 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:20456 pid:5822 tgid:5822 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5310 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
bit_wait+0x11/0xd0 kernel/sched/wait_bit.c:240
__wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52
out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
wait_on_bit include/linux/wait_bit.h:77 [inline]
gfs2_glock_wait+0xbd/0x2a0 fs/gfs2/glock.c:1269
gfs2_glock_nq_init fs/gfs2/glock.h:253 [inline]
__gfs2_lookup+0x134/0x2a0 fs/gfs2/inode.c:999
__lookup_slow+0x2b7/0x410 fs/namei.c:1916
lookup_slow+0x53/0x70 fs/namei.c:1933
walk_component fs/namei.c:2279 [inline]
lookup_last fs/namei.c:2780 [inline]
path_lookupat+0x3f5/0x8c0 fs/namei.c:2804
filename_lookup+0x256/0x5d0 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
ksys_umount fs/namespace.c:2052 [inline]
__do_sys_umount fs/namespace.c:2060 [inline]
__se_sys_umount fs/namespace.c:2058 [inline]
__x64_sys_umount+0xf6/0x170 fs/namespace.c:2058
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: 0033:0x7f988d39c117
RSP: 002b:00007ffc7b140fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f988d40471f RCX: 00007f988d39c117
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc7b141060
RBP: 00007ffc7b141060 R08: 0000000000000000 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc7b142150
R13: 00007f988d40471f R14: 0000000000054aaf R15: 00007ffc7b144310
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e760320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e760320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e760320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5576:
#0: ffff8880343f30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000362b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5807:
1 lock held by syz-executor/5822:
#0: ffff8880575d07e8 (&type->i_mutex_dir_key#21){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
#0: ffff8880575d07e8 (&type->i_mutex_dir_key#21){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1932
1 lock held by syz-executor/5824:
#0: ffffffff8e7665b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e7665b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
3 locks held by kworker/u8:9/6382:
#0: ffff88801b0ac148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x855/0x1650 kernel/workqueue.c:3254
#1: ffffc90019f77c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x87c/0x1650 kernel/workqueue.c:3255
#2: ffffffff8fbc7d08 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by syz.6.1263/10921:
#0: ffffffff8fbc7d08 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8fbc7d08 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
#1: ffffffff8e7665b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e7665b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
4 locks held by syz.4.1265/10925:
1 lock held by syz.2.1264/10928:
#0: ffffffff8e766480 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:347 [inline]
watchdog+0x103d/0x1090 kernel/hung_task.c:516
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10921 Comm: syz.6.1263 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:6197 [inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6236 [inline]
RIP: 0010:zap_class+0xcf/0x340 kernel/locking/lockdep.c:6281
Code: 49 81 fc 00 00 08 00 0f 84 a4 01 00 00 4e 8b 2c e5 40 34 df 93 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 75 00 <41> f6 c6 fc 0f 84 e1 00 00 00 41 c1 ee 08 4a 8d 1c 75 10 34 24 93
RSP: 0018:ffffc9001af57940 EFLAGS: 00000046
RAX: 000000000000df00 RBX: ffffffff9325f2be RCX: 000000000000df00
RDX: ffffffff93df3438 RSI: 0000000000000007 RDI: 000000000005894c
RBP: ffffffff942338b0 R08: ffffffff81af03e8 R09: ffffffff8e760320
R10: dffffc0000000000 R11: fffffbfff20227d7 R12: 0000000000070251
R13: ffffffff943e4b10 R14: 0000000003cc2614 R15: 0000000000000ff7
FS: 0000555577571500(0000) GS:ffff88812556a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7336be12f8 CR3: 0000000034254000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__lockdep_free_key_range kernel/locking/lockdep.c:6407 [inline]
lockdep_unregister_key+0x1c3/0x350 kernel/locking/lockdep.c:6609
__qdisc_destroy+0x167/0x450 net/sched/sch_generic.c:1079
qdisc_put net/sched/sch_generic.c:1105 [inline]
dev_shutdown+0x34c/0x440 net/sched/sch_generic.c:1493
unregister_netdevice_many_notify+0x11a9/0x2380 net/core/dev.c:12405
unregister_netdevice_many net/core/dev.c:12480 [inline]
unregister_netdevice_queue+0x31f/0x360 net/core/dev.c:12294
unregister_netdevice include/linux/netdevice.h:3414 [inline]
__tun_detach+0x6d9/0x15d0 drivers/net/tun.c:621
tun_detach drivers/net/tun.c:637 [inline]
tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3436
__fput+0x44f/0xa70 fs/file_table.c:469
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f476c59aeb9
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:00007ffda0ec3788 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffda0ec3870 RCX: 00007f476c59aeb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000078144 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2e720000 R11: 0000000000000246 R12: 00007ffda0ec38b0
R13: 00007f476c815fac R14: 00000000000781ea R15: 00007f476c815fa0
----------------
Code disassembly (best guess):
0: 49 81 fc 00 00 08 00 cmp $0x80000,%r12
7: 0f 84 a4 01 00 00 je 0x1b1
d: 4e 8b 2c e5 40 34 df mov -0x6c20cbc0(,%r12,8),%r13
14: 93
15: 4d 85 ed test %r13,%r13
18: 0f 94 c0 sete %al
1b: 49 83 c5 f8 add $0xfffffffffffffff8,%r13
1f: 0f 94 c1 sete %cl
22: 08 c1 or %al,%cl
24: 75 d7 jne 0xfffffffd
26: 45 8b 75 00 mov 0x0(%r13),%r14d
* 2a: 41 f6 c6 fc test $0xfc,%r14b <-- trapping instruction
2e: 0f 84 e1 00 00 00 je 0x115
34: 41 c1 ee 08 shr $0x8,%r14d
38: 4a 8d 1c 75 10 34 24 lea -0x6cdbcbf0(,%r14,2),%rbx
3f: 93