INFO: task kworker/u8:3:57 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3 state:D stack:24392 pid:57 tgid:57 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:5)
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2dc/0x7b0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75d/0x11a0 fs/fs-writeback.c:1825
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2054
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
wb_do_writeback fs/fs-writeback.c:2398 [inline]
wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3288 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3371
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:3/57:
#0: ffff88801f6e0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff88801f6e0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3371
#1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3371
#2: ffff88803d5460d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88805ef01568 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
3 locks held by kworker/u9:0/60:
8 locks held by kworker/u8:4/67:
2 locks held by dhcpcd/5462:
#0: ffffffff8f1cbb20 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f1cb918 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
#1: ffffffff8f1cb918 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
#1: ffffffff8f1cb918 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208
2 locks held by getty/5559:
#0: ffff888031d4d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/1:4/5878:
#0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3371
#1: ffffc90004ed7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc90004ed7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3371
#2: ffff888034f58260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
5 locks held by syz.5.105/6824:
2 locks held by syz.7.156/7367:
#0: ffff88803d5460d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88803d5460d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
#1: ffff8880261468c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline]
#1: ffff8880261468c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x209/0xc30 fs/fs-writeback.c:2940
2 locks held by syz-executor/8835:
1 lock held by syz.4.367/9185:
2 locks held by syz.9.369/9207:
3 locks held by syz.1.370/9210:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
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:161 [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:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 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: 60 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: hci6 hci_cmd_sync_work
RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237
Code: 13 25 ff 0f 00 00 39 05 cf 58 b6 11 73 06 89 05 c7 58 b6 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 d0 8c c9
RSP: 0018:ffffc9000126f288 EFLAGS: 00000002
RAX: ffffffff9601a858 RBX: 00000000000003cd RCX: 0000000000000066
RDX: ffffffff9600b6d8 RSI: ffff88801afac958 RDI: 00000000000003cd
RBP: ccedefb1b80cedb0 R08: ffffc9000126f250 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a0a0e0 R12: ffffffff95f0cf08
R13: ffffffff92ffda78 R14: ffff88801afabd00 R15: 0000000000000065
FS: 0000000000000000(0000) GS:ffff888126332000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f97bfd2d000 CR3: 000000006b16c000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
debug_object_activate+0x72/0x520 lib/debugobjects.c:835
debug_timer_activate kernel/time/timer.c:793 [inline]
__mod_timer+0xa73/0xf60 kernel/time/timer.c:1124
schedule_timeout+0x153/0x2c0 kernel/time/sleep_timeout.c:98
__hci_cmd_sync_sk+0x632/0xd10 net/bluetooth/hci_sync.c:176
__hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:263 [inline]
hci_disconnect_sync+0x1ec/0x3c0 net/bluetooth/hci_sync.c:5591
hci_abort_conn_sync+0x14d/0x1190 net/bluetooth/hci_sync.c:-1
hci_cmd_sync_work+0x213/0x400 net/bluetooth/hci_sync.c:332
process_one_work kernel/workqueue.c:3288 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3371
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245