INFO: task syz.1.6637:19891 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.1.6637 state:D stack:27128 pid:19891 tgid:19891 ppid:5598 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1372
deactivate_locked_super+0xbd/0x130 fs/super.c:586
deactivate_super fs/super.c:614 [inline]
deactivate_super+0xea/0x110 fs/super.c:610
put_fs_context+0xac/0x9b0 fs/fs_context.c:498
fscontext_release+0x47/0x60 fs/fsopen.c:79
__fput+0x400/0xb60 fs/file_table.c:512
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:70 [inline]
exit_to_user_mode_loop+0x1d8/0x700 kernel/entry/common.c:101
__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:343 [inline]
do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f62f159e559
RSP: 002b:00007fff094c37e8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fff094c38d0 RCX: 00007f62f159e559
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000005960e R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31820000 R11: 0000000000000246 R12: 00007fff094c3910
R13: 00007f62f1825fac R14: 0000000000059643 R15: 00007f62f1825fa0
INFO: task syz.3.7051:20813 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.3.7051 state:D stack:27608 pid:20813 tgid:20812 ppid:5597 task_flags:0x400040 flags:0x00080802
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
rwsem_down_read_slowpath+0x5af/0xb40 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0xed/0x4c0 kernel/locking/rwsem.c:1576
__super_lock fs/super.c:62 [inline]
super_lock+0x326/0x3f0 fs/super.c:124
__iterate_supers+0x38b/0x4a0 fs/super.c:979
ksys_sync+0x87/0xf0 fs/sync.c:102
__do_sys_sync+0xe/0x20 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f968179e559
RSP: 002b:00007f96825e4028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f9681a25fa0 RCX: 00007f968179e559
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f9681a25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9681a26038 R14: 00007f9681a25fa0 R15: 00007ffdec36d5f8
Showing all locks held in the system:
locks held by kworker/1:0/25: 1, last CPU#1:
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: process_one_work+0x880/0x1b10 kernel/workqueue.c:3361
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by getty/5353: 2, on CPU#0:
#0: ffff888034c8b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032432e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz-executor/5596: 2, on CPU#0:
#0: ffff888058ad00e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888058ad00e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888058ad00e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff888058ad00e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff90289ce0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by kworker/1:5/5729: 1, last CPU#1:
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fdec5e0 (rcu_read_lock){....}-{1:3}, at: process_one_work+0x880/0x1b10 kernel/workqueue.c:3361
locks held by kworker/1:6/5781: 2, last CPU#1:
#0: ffff88801d059d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc9000474fd08 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
locks held by syz.4.3118/12408: 2, on CPU#1:
#0: ffffffff91d849c8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff90289ce0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x1a3/0x1dc0 fs/nfsd/nfsctl.c:2057
locks held by syz.1.6637/19891: 2, on CPU#0:
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff90289ce0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by syz.3.7051/20813: 1, on CPU#0:
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock fs/super.c:62 [inline]
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: super_lock+0x326/0x3f0 fs/super.c:124
locks held by syz.0.7435/21677: 1, on CPU#1:
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock fs/super.c:62 [inline]
#0: ffff8880574860e8 (&type->s_umount_key#104){++++}-{4:4}, at: super_lock+0x326/0x3f0 fs/super.c:124
locks held by syz.7.8976/25083: 2, on CPU#1:
#0: ffff888034dde0e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888034dde0e8 (&type->s_umount_key#104){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888034dde0e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super fs/super.c:613 [inline]
#0: ffff888034dde0e8 (&type->s_umount_key#104){++++}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:610
#1: ffffffff90289ce0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582
locks held by syz.9.9437/26183: 2, last CPU#0:
#0: ffff88803796c460 (sb_writers#3){.+.+}-{0:0}, at: splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103
#1: ffff888034d1e0e8 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:62 [inline]
#1: ffff888034d1e0e8 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x326/0x3f0 fs/super.c:124
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 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: 5781 Comm: kworker/1:6 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_is_held_type+0x53/0x140 kernel/locking/lockdep.c:6012
Code: 56 41 55 41 54 55 53 48 83 ec 08 65 48 8b 2d 6c 2f b9 09 8b 95 a4 0b 00 00 85 d2 0f 85 a7 00 00 00 48 89 fb 41 89 f4 9c 41 5d 48 c7 c7 49 a7 4d 8e e8 40 1a 00 00 65 ff 05 01 76 b9 09 8b 85
RSP: 0018:ffffc9000474fa58 EFLAGS: 00000246
RAX: 00000000ffffffff RBX: ffffffff8fdec580 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8fdec580
RBP: ffff888032e84b00 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffff
R13: 0000000000000246 R14: ffff888033b77800 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888122a46000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8d71d05ff8 CR3: 0000000036b21000 CR4: 00000000003526f0
Call Trace:
lock_is_held include/linux/lockdep.h:249 [inline]
__might_resched+0x241/0x330 kernel/sched/core.c:9226
neigh_periodic_work+0x6ed/0xc10 net/core/neighbour.c:1036
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245