INFO: task syz.6.2311:12725 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.2311 state:D stack:27056 pid:12725 ppid:4518 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f837059e199
RSP: 002b:00007f8371493028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8370825fa0 RCX: 00007f837059e199
RDX: 0000000000000005 RSI: 00002000000001c0 RDI: 0000000000000003
RBP: 00007f83706358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8370826038 R14: 00007f8370825fa0 R15: 00007ffd8bffa588
INFO: task syz.6.2311:12729 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.2311 state:D stack:27056 pid:12729 ppid:4518 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
nfsd_svc+0x61/0xab0 fs/nfsd/nfssvc.c:783
write_threads+0x2ea/0x350 fs/nfsd/nfsctl.c:424
nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f837059e199
RSP: 002b:00007f8371472028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8370826090 RCX: 00007f837059e199
RDX: 0000000000000001 RSI: 0000200000000240 RDI: 0000000000000004
RBP: 00007f83706358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8370826128 R14: 00007f8370826090 R15: 00007ffd8bffa588
INFO: task syz.0.2325:12768 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2325 state:D stack:27056 pid:12768 ppid:4271 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ffb9679e199
RSP: 002b:00007ffb97693028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffb96a25fa0 RCX: 00007ffb9679e199
RDX: 0000000000000005 RSI: 00002000000001c0 RDI: 0000000000000003
RBP: 00007ffb968358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb96a26038 R14: 00007ffb96a25fa0 R15: 00007ffcc37ca0f8
INFO: task syz.0.2325:12769 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2325 state:D stack:27056 pid:12769 ppid:4271 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
nfsd_nrthreads+0x48/0xe0 fs/nfsd/nfssvc.c:280
write_threads+0x1ec/0x350 fs/nfsd/nfsctl.c:428
nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ffb9679e199
RSP: 002b:00007ffb97672028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffb96a26090 RCX: 00007ffb9679e199
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007ffb968358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb96a26128 R14: 00007ffb96a26090 R15: 00007ffcc37ca0f8
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ea50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
2 locks held by getty/4026:
#0: ffff88814d1c6098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
4 locks held by kworker/1:5/4314:
#0: ffff8881432a9138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004907d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff888145351190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888145351190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5850
#3: ffff88801ee90190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88801ee90190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
3 locks held by syz.1.2015/11693:
#0: ffff888077eb7768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff888056fc8460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
3 locks held by syz.6.2311/12725:
#0: ffff88801db43268 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff888030070460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
3 locks held by syz.6.2311/12729:
#0: ffff888059060ae8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff888030070460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_svc+0x61/0xab0 fs/nfsd/nfssvc.c:783
3 locks held by syz.0.2325/12768:
#0: ffff888028c2b268 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff88802d9b8460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
3 locks held by syz.0.2325/12769:
#0: ffff8880685b0d68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff88802d9b8460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nrthreads+0x48/0xe0 fs/nfsd/nfssvc.c:280
3 locks held by syz.2.2352/12856:
#0: ffff8880296405e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff8880587de460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdccf08 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
1 lock held by syz.2.2352/12860:
#0: ffff8880296405e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
4 locks held by udevd/13343:
#0: ffff888053e6bd58 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
#1: ffff888056a23088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
#2: ffff8880656d33a8 (kn->active#5){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8880656d33a8 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff88801ee90190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88801ee90190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
1 lock held by syz.5.2964/15619:
#0: ffffffff8cb33440 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x5e0 kernel/rcu/tree.c:4023
1 lock held by syz.3.2963/15623:
#0: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#0: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741