INFO: task syz.3.1581:13559 blocked for more than 143 seconds.
Tainted: G U syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1581 state:D stack:27160 pid:13559 tgid:13558 ppid:7728 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1347
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xde/0x100 fs/super.c:502
cleanup_mnt+0x225/0x450 fs/namespace.c:1327
task_work_run+0x14d/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x419/0x4b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ead18eec9
RSP: 002b:00007f8eadfc7038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007f8ead3e5fa0 RCX: 00007f8ead18eec9
RDX: 0000200000000140 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007f8ead211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8ead3e6038 R14: 00007f8ead3e5fa0 R15: 00007fff8e244328
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e1c2220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e1c2220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e1c2220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:14/7918:
#0: ffff88801bedf148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc9000bb57d10 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff8e1cd680 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
2 locks held by udevd/11436:
2 locks held by getty/11584:
#0: ffff88814c7220a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e732f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.4.1574/13532:
#0: ffffffff8ff8c250 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e5e9848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b10 fs/nfsd/nfsctl.c:1880
2 locks held by syz.3.1581/13559:
#0: ffff88805d37e0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88805d37e0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88805d37e0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff88805d37e0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e5e9848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
2 locks held by syz-executor/13822:
#0: ffff888066bdc0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888066bdc0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888066bdc0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff888066bdc0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e5e9848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:593
2 locks held by syz.1.2315/16826:
#0: ffffffff8fed24d0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x2d6/0x690 net/core/net_namespace.c:576
#1: ffffffff8e1cd7b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by syz.8.2316/16832:
#0: ffff8880126f0d88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:979 [inline]
#0: ffff8880126f0d88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661
#1: ffffffff8e1cd7b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
3 locks held by syz.8.2316/16833:
4 locks held by syz.8.2316/16841:
#0: ffffffff8ee527e8 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x450 drivers/char/misc.c:125
#1: ffffffff8e0856a8 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:57
#2: ffffffff8e0c59f0 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust kernel/notifier.c:344 [inline]
#2: ffffffff8e0c59f0 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust+0xa8/0x160 kernel/notifier.c:333
#3: ffffffff8e1cd680 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U syzkaller #0 PREEMPT(full)
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 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: 0 Comm: swapper/0 Tainted: G U syzkaller #0 PREEMPT(full)
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 6e 5e 02 e9 c3 09 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 de 1b 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8de07e08 EFLAGS: 000002c2
RAX: 000000000069e80d RBX: 0000000000000000 RCX: ffffffff8b4e2a59
RDX: 0000000000000000 RSI: ffffffff8d8245fd RDI: ffffffff8bd04640
RBP: fffffbfff1bd2f40 R08: 0000000000000001 R09: ffffed10170c6655
R10: ffff8880b86332ab R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8de97a00 R14: ffffffff905ff190 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124e6f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e306ff8 CR3: 0000000075c0e000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f3/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148