INFO: task syz.2.5868:24567 blocked for more than 143 seconds.
Tainted: G
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.5868 state:D stack:27944 pid:24567 tgid:24566 ppid:18711 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
nfsd_nrthreads+0x57/0xd0 fs/nfsd/nfssvc.c:252
write_threads+0x34a/0x600 fs/nfsd/nfsctl.c:445
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
nfsctl_transaction_read+0x82/0xa0 fs/nfsd/nfsctl.c:129
vfs_read+0x1e4/0xb40 fs/read_write.c:572
ksys_read+0x12a/0x250 fs/read_write.c:716
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa3d999e159
RSP: 002b:00007fa3da8cd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fa3d9c25fa0 RCX: 00007fa3d999e159
RDX: 0000000000000064 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007fa3d9a3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3d9c26038 R14: 00007fa3d9c25fa0 R15: 00007ffd07f94498
Showing all locks held in the system:
locks held by kworker/0:1/10: 3, on CPU#0:
#0: ffff88801c05b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc900000f7d08 ((work_completion)(&rfkill_global_led_trigger_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffffffff911aafc0 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_global_led_trigger_worker+0x1b/0x160 net/rfkill/core.c:185
locks held by khungtaskd/32: 1, last CPU#1:
#0: ffffffff8edec5a0 (rcu_read_lock){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by syslogd/4951: 1, last CPU#1:
#0: ffff8880382127f0 (&u->iolock){+.+.}-{4:4}, at: __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2587
locks held by getty/5357: 2, on CPU#1:
#0: ffff88802c88e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032262e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz.8.5632/23800: 3, on CPU#1:
#0: ffff88807508aef0 (&f->f_pos_lock){+.+.}-{4:4}
, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88802b98c460 (sb_writers
#25){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f2899c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.2.5868/24567: 2, on CPU#1:
#0: ffff888034b01cf0 (&f->f_pos_lock
){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffffffff8f2899c0 (
nfsd_mutex){+.+.}-{4:4}, at: nfsd_nrthreads+0x57/0xd0 fs/nfsd/nfssvc.c:252
locks held by kworker/0:13/25676: 3, on CPU#0:
#0: ffff8880242acd40 ((wq_completion)md_misc
){+.+.}-{0:0}
, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc90005d17d08 ((work_completion)(&mddev->sync_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffff8880367dc0a0 (&mddev->suspend_mutex){+.+.}-{4:4}, at: mddev_suspend+0x47c/0x7d0 drivers/md/md.c:479
locks held by syz.9.6388/26599: 3, on CPU#0:
#0: ffff888034b2b430 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88802bd5d2d8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#2: ffffffff8f2899c0 (nfsd_mutex){+.+.}-{4:4}, at: svc_pool_stats_start+0x8e/0x1c0 net/sunrpc/svc_xprt.c:1514
locks held by syz.5.6504/27303: 2, last CPU#0:
#0: ffff88803779e460 (sb_writers#6){.+.+}-{0:0}, at: get_signal+0x1f2a/0x21e0 kernel/signal.c:3097
#1: ffff88807d6f6f18 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff88807d6f6f18 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: shmem_file_write_iter+0x86/0x140 mm/shmem.c:3430
locks held by syz.5.6532/27433: 1, last CPU#0:
#0: ffffffff8edec5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock_dont_migrate include/linux/rcupdate.h:991 [inline]
#0: ffffffff8edec5a0 (rcu_read_lock){....}-{1:3}, at: bpf_test_timer_enter+0xc3/0x2c0 net/bpf/test_run.c:39
locks held by syz.6.6533/27448: 1, on CPU#0:
#0: ffffffff8ecad940 (sched_core_mutex){+.+.}-{4:4}, at: sched_core_get+0x3f/0xa0 kernel/sched/core.c:507
locks held by syz.6.6533/27450: 2, on CPU#0:
#0: ffffffff911aafc0 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_fop_write+0x166/0x580 net/rfkill/core.c:1308
#1: ffff8880694d8ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
locks held by syz.6.6533/27454: 1, on CPU#0:
#0: ffff88802cc62370 (&sig->exec_update_lock){++++}-{4:4}, at: landlock_restrict_sibling_threads+0x1c7/0x14c0 security/landlock/tsync.c:513
locks held by syz.0.6536/27447: 1, on CPU#0:
#0: ffff88802e279190 (&md->type_lock){+.+.}-{4:4}, at: table_load+0x22d/0x7b0 drivers/md/dm-ioctl.c:1636
=============================================
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 09/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 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:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:410
Code: a4 5a fc 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c e9 bd 06 24 06 e8 08 0e ce fc eb a2 e8 91 0e
RSP: 0018:ffffc90000157958 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff85b1a070 RDI: ffffffff9bc75f60
RBP: ffffffff9bc75f20 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 205d323354202020 R12: 0000000000000000
R13: 0000000000000020 R14: fffffbfff378ec41 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888123c4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33f22ff8 CR3: 0000000075cc0000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:2013
serial8250_fifo_wait_for_lsr_thre+0x5f/0xd0 drivers/tty/serial/8250/8250_port.c:3270
__serial8250_console_fifo_write+0xa5/0x290 drivers/tty/serial/8250/8250_port.c:3345
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
serial8250_console_write+0xf46/0x1330 drivers/tty/serial/8250/8250_port.c:3493
nbcon_emit_next_record+0x8f7/0xa70 kernel/printk/nbcon.c:1070
nbcon_emit_one+0x1a8/0x2b0 kernel/printk/nbcon.c:1157
nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245