INFO: task syz.1.286:7112 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.1.286 state:D stack:27944 pid:7112 tgid:7109 ppid:5592 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5520 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7270
__schedule_loop kernel/sched/core.c:7347 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7362
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xcbf/0x1bc0 kernel/locking/mutex.c:821
write_versions+0x9d/0xba0 fs/nfsd/nfsctl.c:708
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
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: 0033:0x7f123ff9e0d9
RSP: 002b:00007f1240e25028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1240226090 RCX: 00007f123ff9e0d9
RDX: 0000000000000001 RSI: 0000200000000b00 RDI: 0000000000000004
RBP: 00007f1240e25090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f1240226128 R14: 00007f1240226090 R15: 00007ffc0661edb8
Showing all locks held in the system:
locks held by khungtaskd/30: 1, last CPU#1:
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6793
locks held by getty/5349: 2, on CPU#0:
#0: ffff88803795d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by syz-executor/5595: 1, last CPU#0:
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
#0: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495
locks held by kworker/u9:3/5604: 3, on CPU#1:
#0: ffff888055a7d140 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc90004447d08 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffff88803b700ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x18a/0x470 net/bluetooth/hci_sync.c:331
locks held by kworker/1:6/5724: 4, last CPU#1:
#0: ffff88801c053140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc90004cf7d08 (drain_vmap_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff8efbe5e0 (vmap_purge_lock){+.+.}-{4:4}, at: drain_vmap_area_work+0x17/0x40 mm/vmalloc.c:2452
#3: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: spin_trylock include/linux/spinlock.h:359 [inline]
#3: ffffffff8ede9d40 (rcu_read_lock){....}-{1:3}, at: __free_frozen_pages+0x57e/0x10f0 mm/page_alloc.c:2986
locks held by syz.1.286/7110: 3, on CPU#0:
#0: ffff8880247ab970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88802c236460 (sb_writers#20){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f2815c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.1.286/7112: 3, on CPU#1:
#0: ffff88807d0022b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88802c236460 (sb_writers#20){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f2815c0 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x9d/0xba0 fs/nfsd/nfsctl.c:708
locks held by syz-executor/7242: 3, on CPU#1:
#0: ffff88803b40cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff88803b40c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x37e/0x13c0 net/bluetooth/hci_sync.c:5575
#2: ffffffff8edf57e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
locks held by syz-executor/8429: 1, on CPU#1:
#0: ffff888034accea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 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 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 48 Comm: kworker/u8:3 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: 0x0 (events_unbound)
RIP: 0010:__list_add include/linux/list.h:172 [inline]
RIP: 0010:list_add_tail include/linux/list.h:199 [inline]
RIP: 0010:list_move_tail include/linux/list.h:350 [inline]
RIP: 0010:move_linked_works+0x1b9/0x2f0 kernel/workqueue.c:1173
Code: 4c 89 73 08 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 0b 01 00 00 4c 89 f8 4c 89 7b 10 48 c1 e8 03 80 3c 28 00 0f 85 e9 00 00 00 <4d> 89 27 e8 af d7 3b 00 48 89 d8 48 c1 e8 03 80 3c 28 00 75 77 48
RSP: 0018:ffffc90000b97d20 EFLAGS: 00000046
RAX: 1ffff11004858ce9 RBX: ffff888056530690 RCX: 0000000000000001
RDX: ffff88801c77cb00 RSI: ffffffff81cf3ba4 RDI: ffff8880565306a0
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888056530698
R13: ffff8880558d0690 R14: ffff8880242c6748 R15: ffff8880242c6748
FS: 0000000000000000(0000) GS:ffff888123b86000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bd3f4b9418 CR3: 000000000eb94000 CR4: 00000000003526f0
Call Trace:
assign_work+0x1a2/0x440 kernel/workqueue.c:1235
worker_thread+0x355/0xe50 kernel/workqueue.c:3550
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