INFO: task syz.1.516:10160 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.1.516 state:D
stack:25920 pid:10160 tgid:10159 ppid:5827 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7020
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
sync_bdevs+0x27e/0x470 block/bdev.c:1305
ksys_sync+0xb9/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f517878f749
RSP: 002b:00007f517967b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f51789e5fa0 RCX: 00007f517878f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f51789e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f51789e6038 R14: 00007f51789e5fa0 R15: 00007ffedea5c5f8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:5/142:
2 locks held by getty/5584:
#0: ffff888034c350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211
1 lock held by udevd/5969:
#0: ffff88802560b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
5 locks held by syz-executor/8317:
#0: ffff88805cad0ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
#0: ffff88805cad0ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5b0 net/bluetooth/hci_core.c:2715
#1: ffff88805cad00c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x1100 net/bluetooth/hci_sync.c:5329
#2: ffffffff8f683f08 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff8f683f08 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2643
#3: ffff888051b29338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5b0 net/bluetooth/l2cap_core.c:1763
#4: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#4: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956
1 lock held by syz.1.516/10160:
#0: ffff88802560b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470 block/bdev.c:1305
3 locks held by kworker/1:14/12398:
#0: ffff888021ab7948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc90003a9fb80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff8880b8728ec8 (lock#6){..-.}-{3:3}, at: local_lock_acquire include/linux/local_lock_internal.h:41 [inline]
#2: ffff8880b8728ec8 (lock#6){..-.}-{3:3}, at: kcov_remote_stop+0x78/0x6f0 kernel/kcov.c:1016
2 locks held by syz.9.922/14765:
#0: ffffffff8f512448 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f512448 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
#1: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:956
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [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:363 [inline]
watchdog+0xe40/0xe90 kernel/hung_task.c:557
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12818 Comm: kworker/u8:34 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: 0x0 (bat_events)
RIP: 0010:__list_add include/linux/list.h:163 [inline]
RIP: 0010:list_add_tail include/linux/list.h:191 [inline]
RIP: 0010:list_move_tail include/linux/list.h:319 [inline]
RIP: 0010:move_linked_works kernel/workqueue.c:1156 [inline]
RIP: 0010:assign_work+0x33b/0x5b0 kernel/workqueue.c:1218
Code: e8 03 42 80 3c 20 00 74 08 48 89 ef e8 5e 7e 9c 00 48 8b 44 24 18 48 89 43 08 4c 8d 7b 10 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 ff e8 3b 7e 9c 00 4d 89 37 4c 89 f0 48 c1 e8 03 42 80
RSP: 0018:ffffc90016f77bf0 EFLAGS: 00000046
RAX: 1ffff1100f7a0a3c RBX: ffff88807bd051d0 RCX: ffff8880554e9e80
RDX: 0000000000000000 RSI: ffff8880325b4940 RDI: ffff88807bd051d8
RBP: ffff88807bd051d8 R08: ffff88814c9eaf8b R09: 1ffff1102993d5f1
R10: dffffc0000000000 R11: ffffed102993d5f2 R12: dffffc0000000000
R13: ffff888032fb1008 R14: ffff8880325b4940 R15: ffff88807bd051e0
FS: 0000000000000000(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c42dcd2 CR3: 00000000325c0000 CR4: 00000000003526f0
Call Trace:
worker_thread+0x8ff/0xee0 kernel/workqueue.c:3442
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246