INFO: task syz.3.2987:21430 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2987 state:D stack:27528 pid:21430 tgid:21430 ppid:18678 task_flags:0x40044c flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe6/0x5fa0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
__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:575
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1353
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
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x829/0x2a30 kernel/exit.c:971
do_group_exit+0xd5/0x2a0 kernel/exit.c:1112
get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x86/0x4b0 kernel/entry/common.c:75
__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_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ea/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbcdf5b84e
RSP: 002b:00007ffbceea2f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007ffbceea36c0 RCX: 00007ffbcdf5b84e
RDX: 00007ffbceea2fb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffbce0316e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffbce216128 R14: 00007ffbce216090 R15: 00007fff81094968
INFO: task syz-executor:26512 blocked for more than 164 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24312 pid:26512 tgid:26512 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe6/0x5fa0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
__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:575
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1353
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:44 [inline]
exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75
__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_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ea/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8046b9c1d7
RSP: 002b:00007ffe48754508 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f8046c30b3b RCX: 00007f8046b9c1d7
RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffe48755650
RBP: 00007ffe4875563c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe48755650
R13: 00007f8046c30b3b R14: 000000000016c9b6 R15: 00007ffe48755690
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:302 [inline]
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz.3.2987/21430:
#0: ffff8880288fe0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880288fe0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880288fe0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff8880288fe0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ea47ee8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz-executor/26512:
#0: ffff88807b7e80e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807b7e80e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807b7e80e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807b7e80e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ea47ee8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz.5.4130/27028:
#0: ffffffff904adad0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea47ee8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
2 locks held by syz-executor/27231:
#0: ffff88802acde0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88802acde0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88802acde0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88802acde0e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ea47ee8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by syz.3.4574/28976:
#0: ffff88805d5e20e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88805d5e20e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88805d5e20e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88805d5e20e0 (&type->s_umount_key#60){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ea47ee8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
5 locks held by kworker/u10:1/29800:
#0: ffff88801c2e7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc90004e7fc98 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903e8330 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xab/0x830 net/core/net_namespace.c:670
#3: ffffffff90400c68 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#3: ffffffff90400c68 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248
#4: ffffffff8e5eedb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246