INFO: task syz-executor:29436 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:22424 pid:29436 tgid:29436 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
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+0x157/0x670 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x652/0x840 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f524559e097
RSP: 002b:00007ffdcc41eb98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f52456321ca RCX: 00007f524559e097
RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffdcc41fce0
RBP: 00007ffdcc41fccc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdcc41fce0
R13: 00007f52456321ca R14: 00000000001c67cd R15: 00007ffdcc41fd20
INFO: task syz-executor:6327 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24104 pid:6327 tgid:6327 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
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+0x157/0x670 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x652/0x840 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f533af9e097
RSP: 002b:00007ffd5ff6b838 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f533b0321ca RCX: 00007f533af9e097
RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffd5ff6c980
RBP: 00007ffd5ff6c96c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd5ff6c980
R13: 00007f533b0321ca R14: 00000000001c680b R15: 00007ffd5ff6c9c0
INFO: task syz-executor:6866 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24296 pid:6866 tgid:6866 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
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+0x157/0x670 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x652/0x840 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f83ceb9e097
RSP: 002b:00007ffdd48c08e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f83cec321ca RCX: 00007f83ceb9e097
RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffdd48c1a30
RBP: 00007ffdd48c1a1c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdd48c1a30
R13: 00007f83cec321ca R14: 00000000001c744a R15: 00007ffdd48c1a70
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e7e5360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e7e5360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e7e5360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz-executor/29436:
#0: ffff888064f980d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888064f980d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888064f980d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff888064f980d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec623e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/6327:
#0: ffff8880379820d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880379820d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880379820d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff8880379820d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec623e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/6866:
#0: ffff88807bcd00d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807bcd00d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807bcd00d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807bcd00d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec623e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.9.7144/9250:
#0: ffffffff906b4a88 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec623e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1948
2 locks held by syz-executor/9377:
#0: ffff888044e280d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888044e280d8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888044e280d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff888044e280d8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec623e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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:162 [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:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245