INFO: task syz.4.7017:21334 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.4.7017 state:D stack:27264 pid:21334 tgid:21333 ppid:13258 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5581 [inline]
__schedule+0x1b47/0x5b40 kernel/sched/core.c:7384
__schedule_loop kernel/sched/core.c:7461 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7476
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7533
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
nfsd_nl_threads_set_doit+0x2b9/0xc30 fs/nfsd/nfsctl.c:1712
genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x7c3/0xae0 net/netlink/af_netlink.c:1916
sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800
__sock_sendmsg net/socket.c:818 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2715
___sys_sendmsg+0x2a5/0x360 net/socket.c:2769
__sys_sendmsg net/socket.c:2801 [inline]
__do_sys_sendmsg net/socket.c:2806 [inline]
__se_sys_sendmsg net/socket.c:2804 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3d5b19e159
RSP: 002b:00007f3d5c037028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3d5b425fa0 RCX: 00007f3d5b19e159
RDX: 0000000000040070 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007f3d5b23506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d5b426038 R14: 00007f3d5b425fa0 R15: 00007ffca8d75c68
Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#1:
#0: ffffffff8f033e98 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff8f033e98 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:493 [inline]
#0: ffffffff8f033e98 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
#1: ffffffff9b1e00d8 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline]
#1: ffffffff9b1e00d8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413
locks held by khungtaskd/34: 1, last CPU#0:
#0: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5371: 2, on CPU#1:
#0: ffff888035a750a0 (&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
locks held by syz-executor/5600: 1, last CPU#0:
#0: ffff8880352dd900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:530 [inline]
#0: ffff8880352dd900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1323
locks held by kworker/0:7/5758: 6, on CPU#0:
#0: ffff8880232cd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880232cd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880232cd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff8880232cd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004a3fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004a3fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004a3fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004a3fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff888029af31d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff888029af31d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff888029af7568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3270 [inline]
#3: ffff888029af7568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5482 [inline]
#3: ffff888029af7568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
#3: ffff888029af7568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
#3: ffff888029af7568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5971
#4: ffff888029a6f660 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5483 [inline]
#4: ffff888029a6f660 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
#4: ffff888029a6f660 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
#4: ffff888029a6f660 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5971
#5: ffffffff8ff1af88 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14d/0x1810 drivers/usb/core/hub.c:3085
locks held by kworker/1:5/5783: 4, last CPU#1:
#0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004b37c40 (((io_key_has_sqarray).work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004b37c40 (((io_key_has_sqarray).work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004b37c40 (((io_key_has_sqarray).work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004b37c40 (((io_key_has_sqarray).work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffffffff8efe5e30 (cpu_hotplug_lock){++++}-{0:0}, at: __static_key_slow_dec kernel/jump_label.c:320 [inline]
#2: ffffffff8efe5e30 (cpu_hotplug_lock){++++}-{0:0}, at: jump_label_update_timeout+0x16/0x30 kernel/jump_label.c:329
#3: ffffffff8f238860 (jump_label_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#3: ffffffff8f238860 (jump_label_mutex){+.+.}-{4:4}, at: __static_key_slow_dec_cpuslocked+0x3a/0x110 kernel/jump_label.c:300
locks held by syz.2.6420/19410: 2, on CPU#1:
#0: ffffffff906df268 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f49de60 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2079
locks held by syz.4.7017/21334: 2, on CPU#1:
#0: ffffffff906df268 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f49de60 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2b9/0xc30 fs/nfsd/nfsctl.c:1712
locks held by syz.9.8602/27958: 2, last CPU#1:
#0: ffff88807caf5900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:530 [inline]
#0: ffff88807caf5900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1323
#1: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8f15a3a0 (rcu_read_lock){....}-{1:3}, at: folio_lruvec_lock_irqsave+0x24/0x560 mm/memcontrol.c:1541
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 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_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 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+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline]
watchdog+0x1058/0x10d0 kernel/hung_task.c:598
kthread+0x38b/0x480 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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:wq_watchdog_touch+0xb4/0x160 kernel/workqueue.c:8248
Code: d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 b2 db aa 00 49 c7 c6 80 63 df 93 4c 03 33 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 82 dc aa 00 49 89 2e eb 18 e8 08 04 39 00 48 8d
RSP: 0018:ffffc900001578a8 EFLAGS: 00000046
RAX: 1ffff110170a4870 RBX: ffffffff8ea477d8 RCX: ffff88801e288000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 000000010000660b R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8bfde9f0 R12: 00000000000036b0
R13: 0000000100005b1d R14: ffff8880b8524380 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88812472e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30723ffc CR3: 00000000745a8000 CR4: 00000000003526f0
Call Trace:
touch_nmi_watchdog include/linux/nmi.h:151 [inline]
wait_for_lsr+0x151/0x2f0 drivers/tty/serial/8250/8250_port.c:2043
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3294 [inline]
__serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3369
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3402 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3456 [inline]
serial8250_console_write+0xa7e/0x1200 drivers/tty/serial/8250/8250_port.c:3520
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x6d9/0x8d0 kernel/printk/nbcon.c:1271
kthread+0x38b/0x480 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