INFO: task syz.4.3641:16715 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.4.3641 state:D stack:26328 pid:16715 tgid:16714 ppid:13676 task_flags:0x400140 flags:0x00080006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7197
__schedule_loop kernel/sched/core.c:7276 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7572
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1667
__rt_mutex_slowlock kernel/locking/rtmutex.c:1744 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1784 [inline]
rt_mutex_slowlock+0x2dc/0x780 kernel/locking/rtmutex.c:1824
__rt_mutex_lock kernel/locking/rtmutex.c:1839 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:541 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:559
nfsd_nl_[ 791.853596][ T39] nfsd_nl_listener_set_doit+0x13e/0x1630 fs/nfsd/nfsctl.c:1954
genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2551
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1895
sock_sendmsg_nosec+0x112/0x150 net/socket.c:797
__sock_sendmsg net/socket.c:812 [inline]
____sys_sendmsg+0x55c/0x870 net/socket.c:2716
___sys_sendmsg+0x2a5/0x360 net/socket.c:2770
__sys_sendmsg net/socket.c:2802 [inline]
__do_sys_sendmsg net/socket.c:2807 [inline]
__se_sys_sendmsg net/socket.c:2805 [inline]
__x64_sys_sendmsg+0x1c3/0x2a0 net/socket.c:2805
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8e1173cdd9
RSP: 002b:00007f8e0f996028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8e119b5fa0 RCX: 00007f8e1173cdd9
RDX: 0000000004040014 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f8e117d2d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e119b6038 R14: 00007f8e119b5fa0 R15: 00007ffdcec73258
</TASK>
Showing all locks held in the system:
5 locks held by kworker/0:0/9:
#0: ffff888021ec2538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3281
#1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3282
#2: ffff88802a384210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1038 [inline]
#2: ffff88802a384210 (&dev->mutex){....}-{4:4}, at: hub_event+0x17c/0x4f60 drivers/usb/core/hub.c:5899
#3: ffff888037b32210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1038 [inline]
#3: ffff888037b32210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1074
#4: ffff8880263131d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1038 [inline]
#4: ffff8880263131d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1074
4 locks held by pr/legacy/17:
#0: ffffffff8e1ba4e0 (console_lock){+.+.}-{0:0}, at: legacy_kthread_func+0x1a3/0x250 kernel/printk/printk.c:3711
#1: ffffffff8e0a1dd8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
#1: ffffffff8e0a1dd8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
#1: ffffffff8e0a1dd8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
#1: ffffffff8e0a1dd8 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfa/0xb90 kernel/printk/printk.c:3246
#2: ffffffff99dc6bf8 (&port_lock_key){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffffffff99dc6bf8 (&port_lock_key){+.+.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
#2: ffffffff99dc6bf8 (&port_lock_key){+.+.}-{3:3}, at: serial8250_console_write+0x179/0x1b90 drivers/tty/serial/8250/8250_port.c:3316
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
1 lock held by khungtaskd/39:
#0: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
6 locks held by kworker/u8:12/1914:
#0: ffff8880323bd138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3281
#1: ffffc90006e0fc40 ((work_completion)(&(&bat_priv->tt.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3282
#2: ffffffff8e05f380 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#4: ffff8880b873b820 (&rq->__lock){-...}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:656
#5: ffff8880b87244c8 (psi_seq){-...}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
2 locks held by getty/5363:
#0: ffff888035b7a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
7 locks held by kworker/1:5/5621:
#0: ffff88813fe0e538 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3281
#1: ffffc90005107c40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3282
#2: ffffffff8e05f380 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#4: ffffffff8f6bec38 (&tbl->lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock_rt.h:90 [inline]
#4: ffffffff8f6bec38 (&tbl->lock){+...}-{3:3}, at: neigh_periodic_work+0xc64/0xe90 net/core/neighbour.c:1040
#5: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#5: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#5: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#6: ffff888057cbc740 (&dir->lock#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#6: ffff888057cbc740 (&dir->lock#2){+.+.}-{3:3}, at: ref_tracker_free+0x13d/0x820 lib/ref_tracker.c:310
2 locks held by syz.5.3166/14985:
#0: ffffffff8f6024c0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8e4ec158 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x13e/0x1630 fs/nfsd/nfsctl.c:1954
2 locks held by syz.4.3641/16715:
#0: ffffffff8f6024c0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8e4ec158 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x13e/0x1630 fs/nfsd/nfsctl.c:1954
2 locks held by syz.2.3913/18436:
#0: ffffffff8f6024c0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8e4ec158 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x13e/0x1630 fs/nfsd/nfsctl.c:1954
4 locks held by syz.8.4987/23663:
#0: ffff88802a8c03b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
#0: ffff88802a8c03b0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x194/0x9e0 mm/mmap.c:1284
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#2: ffff88803a80c598 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88803a80c598 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
2 locks held by syz.1.4989/23667:
#0: ffff88805b71ae48 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e1c8240 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
1 lock held by syz.7.4988/23668:
#0: ffff888028d24e58 (&sighand->siglock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:96 [inline]
#0: ffff888028d24e58 (&sighand->siglock){+.+.}-{3:3}, at: copy_process+0x70e/0x4450 kernel/fork.c:2081
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
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+0xfd3/0x1030 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
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 3e fb 7c fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1f 95 e6 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 8a 4c ef 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff33b8d00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99dc6eb0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85482090 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99dc6c20 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125cc7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557bf09a38 CR3: 0000000028eb4000 CR4: 00000000003526f0
Call Trace:
<TASK>
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
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
</TASK>