INFO: task syz.8.4494:22249 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.8.4494 state:D stack:28080 pid:22249 tgid:22248 ppid:20320 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f41de79e019
RSP: 002b:00007f41df6cc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f41dea25fa0 RCX: 00007f41de79e019
RDX: 0000000000000000 RSI: 00002000000004c0 RDI: 0000000000000003
RBP: 00007f41de83500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f41dea26038 R14: 00007f41dea25fa0 R15: 00007ffc57b53328
INFO: task syz.6.4514:22309 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.4514 state:D stack:28424 pid:22309 tgid:22308 ppid:20786 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e63b9e019
RSP: 002b:00007f5e649bf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5e63e25fa0 RCX: 00007f5e63b9e019
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000003
RBP: 00007f5e63c3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5e63e26038 R14: 00007f5e63e25fa0 R15: 00007ffdaa6fd698
Showing all locks held in the system:
1 lock held by khungtaskd/32:
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:6/878:
#0: ffff8880b863b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:667
#1: ffff8880b8624440 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
2 locks held by getty/5373:
#0: ffff888032f160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
2 locks held by kworker/u9:6/5636:
#0: ffff888026ccf140 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888026ccf140 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc9000207fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000207fc40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
2 locks held by kworker/u8:13/6397:
#0: ffff88801b064140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801b064140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffff8880b8624440 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
2 locks held by kworker/u9:2/15401:
#0: ffff888026ccf140 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888026ccf140 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90006d77c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90006d77c40 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
3 locks held by kworker/0:9/16173:
#0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc9000461fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000461fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff888035d68250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1fd/0x3b0 drivers/net/netdevsim/fib.c:1490
6 locks held by syz.1.4389/21774:
#0: ffff88807c1b3430 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888036150450 (sb_writers#34){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff888036150450 (sb_writers#34){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8e6c0 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x39d/0x5a0 fs/nfsd/nfsctl.c:432
#3: ffffffff8e9e75f0 (cpu_hotplug_lock){++++}-{0:0}, at: kmem_cache_destroy+0x60/0x180 mm/slab_common.c:556
#4: ffffffff8ec67ba8 (slab_mutex){+.+.}-{4:4}, at: kmem_cache_destroy+0x6e/0x180 mm/slab_common.c:557
#5: ffffffff8eb5fe38 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
4 locks held by kworker/u8:10/21877:
#0: ffff888032aee940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888032aee940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90003dbfc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90003dbfc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff88802a032990 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:572 [inline]
#2: ffff88802a032990 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0x67/0x14d0 kernel/sched/core.c:4292
#3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: ieee80211_sta_active_ibss+0xc7/0x330 net/mac80211/ibss.c:628
3 locks held by syz.8.4494/22249:
#0: ffff88807afdb5f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88804d986450 (sb_writers#34){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff88804d986450 (sb_writers#34){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8e6c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
3 locks held by syz.6.4514/22309:
#0: ffff888022f12b70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88803333a450 (sb_writers#34){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff88803333a450 (sb_writers#34){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8e6c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
3 locks held by syz-executor/24287:
#0: ffffffff9002dec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff9002dec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff9002dec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
#1: ffff8880640e1610 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_open+0x227/0x420 drivers/net/wireguard/device.c:50
#2: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
=============================================
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 07/16/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245