INFO: task syz-executor:9876 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24144 pid:9876 tgid:9876 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
deactivate_super fs/super.c:509 [inline]
deactivate_super+0xe7/0x110 fs/super.c:505
cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
task_work_run+0x150/0x240 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+0x100/0x4a0 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+0x668/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f63d159d9d7
RSP: 002b:00007ffc6c2d8308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f63d1632050 RCX: 00007f63d159d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc6c2d83c0
RBP: 00007ffc6c2d83c0 R08: 00007ffc6c2d93c0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc6c2d9450
R13: 00007f63d1632050 R14: 0000000000066bdf R15: 00007ffc6c2d9490
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e7e7720 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e7720 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e7720 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
1 lock held by syz.3.864/9475:
2 locks held by syz-executor/9876:
#0: ffff88807b53c0e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807b53c0e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807b53c0e0 (&type->s_umount_key#58){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807b53c0e0 (&type->s_umount_key#58){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec585a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.2.1318/11456:
#0: ffffffff906c1610 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec585a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x6c1/0xc00 fs/nfsd/nfsctl.c:1607
3 locks held by kworker/u11:2/11455:
1 lock held by syz.1.1395/11781:
2 locks held by syz.5.1688/13114:
#0: ffff88807a2fe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807a2fe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807a2fe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807a2fe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec585a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by kworker/0:1/13460:
#0: ffff88813fe63148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc90003827d08 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
2 locks held by syz.6.1788/13568:
#0: ffffffff906c1610 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec585a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1903
1 lock held by syz-executor/13825:
2 locks held by syz.3.1876/13974:
#0: ffffffff906152e8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff906152e8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3436
#1: ffffffff8e7f3338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by dhcpcd/14001:
#0: ffff88805b1b2488 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#0: ffff88805b1b2488 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661
#1: ffffffff8e7f3338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xd25/0x1050 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13460 Comm: kworker/0:1 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events destroy_super_work
RIP: 0010:__bfs+0x1c7/0x2a0 kernel/locking/lockdep.c:1815
Code: 81 e3 ff 0f 00 00 39 1d 67 5f 30 14 48 89 04 f5 40 7c cf 96 73 11 89 1d 57 5f 30 14 eb 09 0f 1f 44 00 00 4c 89 78 30 48 8b 00 <4c> 39 c0 75 f4 e9 22 ff ff ff b8 01 00 00 00 48 83 c4 30 5b 5d 41
RSP: 0018:ffffc900038274d8 EFLAGS: 00000006
RAX: ffffffff979c87c8 RBX: 00000000000000cf RCX: 00000000000000d2
RDX: ffffffff9614af30 RSI: 00000000000000d2 RDI: ffffffff97997138
RBP: 0000000000000030 R08: ffffffff9614af60 R09: 0000000000000004
R10: ffffc90003827670 R11: 0000000000000000 R12: ffffffff81e3ff60
R13: ffffc90003827580 R14: ffffffff81e40d70 R15: ffffffff97997138
FS: 0000000000000000(0000) GS:ffff888124346000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c5ef1634b0 CR3: 00000000362b8000 CR4: 00000000003526f0
Call Trace:
__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
check_irq_usage+0xe5/0x810 kernel/locking/lockdep.c:2796
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+0x14cf/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
debug_object_activate+0x144/0x490 lib/debugobjects.c:835
debug_timer_activate kernel/time/timer.c:793 [inline]
__mod_timer+0x845/0xca0 kernel/time/timer.c:1124
add_timer_global+0x8e/0xd0 kernel/time/timer.c:1283
__queue_delayed_work+0x33f/0x470 kernel/workqueue.c:2539
queue_delayed_work_on+0x180/0x1e0 kernel/workqueue.c:2574
queue_delayed_work include/linux/workqueue.h:684 [inline]
schedule_delayed_work include/linux/workqueue.h:824 [inline]
__debug_check_no_obj_freed lib/debugobjects.c:1139 [inline]
debug_check_no_obj_freed+0x3c3/0x630 lib/debugobjects.c:1146
slab_free_hook mm/slub.c:2616 [inline]
slab_free mm/slub.c:6165 [inline]
kfree+0x38f/0x6b0 mm/slub.c:6483
security_sb_free+0x9d/0x1a0 security/security.c:934
destroy_super_work+0x2b/0x330 fs/super.c:280
process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245