INFO: task syz-executor:8113 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:21480 pid:8113 ppid:1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6701
schedule+0xbd/0x170 kernel/sched/core.c:6775
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
nfsd_shutdown_threads+0x53/0x1a0 fs/nfsd/nfssvc.c:638
nfsd_umount+0x42/0xc0 fs/nfsd/nfsctl.c:1464
deactivate_locked_super+0x97/0x100 fs/super.c:481
cleanup_mnt+0x3d7/0x460 fs/namespace.c:1259
task_work_run+0x1d4/0x260 kernel/task_work.c:245
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:180
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
__syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f729959f397
RSP: 002b:00007ffc157e6bf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f72996344bb RCX: 00007f729959f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc157e6cb0
RBP: 00007ffc157e6cb0 R08: 00007ffc157e7cb0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc157e7d40
R13: 00007f72996344bb R14: 0000000000037802 R15: 00007ffc157e7d80
Showing all locks held in the system:
3 locks held by kworker/1:1/27:
1 lock held by khungtaskd/29:
#0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6635
3 locks held by kworker/u4:4/59:
2 locks held by getty/5531:
#0: ffff88802d4130a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
4 locks held by udevd/5768:
3 locks held by syz.0.604/7770:
#0: ffff88807f3f6848 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040
#1: ffff88807b334418 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
#2: ffffffff8d3e1c88 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_svc+0x65/0xab0 fs/nfsd/nfssvc.c:788
2 locks held by syz-executor/8113:
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
#1: ffffffff8d3e1c88 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x53/0x1a0 fs/nfsd/nfssvc.c:638
2 locks held by kworker/0:7/9078:
#0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc90004d9fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc90004d9fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
1 lock held by syz.8.983/9392:
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: super_lock+0x189/0x390 fs/super.c:117
3 locks held by syz.5.1127/9988:
#0: ffff88805075a5c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040
#1: ffff88807e0a8418 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580
#2: ffffffff8d3e1c88 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb7/0xfa0 fs/nfsd/nfsctl.c:843
1 lock held by syz.1.1366/11098:
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880782400e0 (&type->s_umount_key#76){++++}-{3:3}, at: super_lock+0x189/0x390 fs/super.c:117
3 locks held by syz.7.1433/11498:
1 lock held by syz.7.1506/11800:
3 locks held by dhcpcd-run-hook/12027:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf59/0xfa0 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 65 8b 05 fd 57 72 75 65 8b 0d f2 57 72 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04
RSP: 0018:ffffc900001179e8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 36551cbf92390a00
RDX: 0000000000000000 RSI: ffffffff8b1d3b80 RDI: ffffffff8b1d3b40
RBP: ffffc90000117b50 R08: ffffffff8e8c316f R09: 1ffffffff1d1862d
R10: dffffc0000000000 R11: fffffbfff1d1862e R12: ffffffff8a586692
R13: dffffc0000000000 R14: ffff88801fb50d00 R15: 1ffff92000022f54
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f0d622c138 CR3: 000000007b260000 CR4: 00000000003506e0
Call Trace:
rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0xb5/0x8c0 kernel/locking/lockdep.c:5767
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0x28b/0x600 net/batman-adv/network-coding.c:719
process_one_work kernel/workqueue.c:2657 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293