INFO: task kworker/u8:8:1039 blocked in I/O wait for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:8 state:D stack:23808 pid:1039 tgid:1039 ppid:2 task_flags:0x4208060 flags:0x00[ 280.630812][ T38] task:kworker/u8:8 state:D stack:23808 pid:1039 tgid:1039 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
io_schedule+0x80/0xe0 kernel/sched/core.c:8154
TXN_SLEEP_DROP_LOCK fs/jfs/jfs_txnmgr.c:125 [inline]
txBegin+0x281/0xbe0 fs/jfs/jfs_txnmgr.c:376
jfs_commit_inode+0x1b3/0x530 fs/jfs/inode.c:107
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1607 [inline]
__writeback_single_inode+0x6af/0xf90 fs/fs-writeback.c:1850
writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2079
wb_writeback+0x41c/0xad0 fs/fs-writeback.c:2264
wb_do_writeback fs/fs-writeback.c:2432 [inline]
wb_workfn+0x437/0x10f0 fs/fs-writeback.c:2477
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
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
INFO: task syz-executor:5599 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:20928 pid:5599 tgid:5599 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
wb_wait_for_completion+0x3b2/0x700 fs/fs-writeback.c:227
__writeback_inodes_sb_nr+0x246/0x2e0 fs/fs-writeback.c:2933
sync_filesystem+0xa2/0x250 fs/sync.c:54
generic_shutdown_super+0x77/0x2d0 fs/super.c:626
kill_block_super+0x44/0x90 fs/super.c:1665
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe02b6f0d7
RSP: 002b:00007ffc0dcc9e78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007efe02c0330a RCX: 00007efe02b6f0d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc0dcc9f30
RBP: 00007ffc0dcc9f30 R08: 00007ffc0dccaf30 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc0dccafc0
R13: 00007efe02c0330a R14: 000000000001ed2f R15: 00007ffc0dccb000
INFO: task syz.2.56:6115 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.56 state:D stack:28112 pid:6115 tgid:6114 ppid:5601 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787
__rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114
rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
__down_read kernel/locking/rwsem.c:1502 [inline]
down_read+0x132/0x200 kernel/locking/rwsem.c:1576
__super_lock fs/super.c:60 [inline]
super_lock+0x2d6/0x3d0 fs/super.c:122
__iterate_supers+0x120/0x240 fs/super.c:866
ksys_sync fs/sync.c:104 [inline]
__ia32_sys_sync+0xbe/0x120 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f406792de99
RSP: 002b:00007f4065b86028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f4067bb5fa0 RCX: 00007f406792de99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f4067bb5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4067bb6038 R14: 00007f4067bb5fa0 R15: 00007ffeab4e9d98
Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
#0: ffff888032fc1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888032fc1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90000117c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90000117c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4229
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:7/1030:
2 locks held by kworker/u8:8/1039:
#0: ffff88801eae0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801eae0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90005c97c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90005c97c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
7 locks held by kworker/u8:10/1293:
#0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900063c7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900063c7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8f5a2a00 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673
#3: ffff888039b12160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff888039b12160 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
#3: ffff888039b12160 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:557
#4: ffff888012774310 (&devlink->lock_key#7){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
#4: ffff888012774310 (&devlink->lock_key#7){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
#4: ffff888012774310 (&devlink->lock_key#7){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:557
#5: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x173/0x800 drivers/net/netdevsim/netdev.c:1191
#6: ffff888020e9d060 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2847 [inline]
#6: ffff888020e9d060 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x5bb/0x2110 net/core/dev.c:12406
1 lock held by syslogd/4946:
#0: ffff8880341ea298 (&si->socket.wq.wait){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff8880341ea298 (&si->socket.wq.wait){+.+.}-{3:3}, at: finish_wait+0xbe/0x1e0 kernel/sched/wait.c:394
3 locks held by klogd/4953:
1 lock held by udevd/4964:
2 locks held by dhcpcd/5259:
#0: ffff88802c1cc928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe7/0xee0 net/netlink/af_netlink.c:2273
#1: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dump_ifinfo+0xa74/0x14b0 net/core/rtnetlink.c:2562
2 locks held by getty/5352:
#0: ffff8880373fb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5599:
#0: ffff88803aaae0d0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88803aaae0d0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88803aaae0d0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
3 locks held by kworker/0:6/5793:
1 lock held by syz.2.56/6115:
#0: ffff88803aaae0d0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88803aaae0d0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
1 lock held by syz-executor/7555:
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
1 lock held by syz-executor/7812:
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
1 lock held by syz-executor/7846:
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
2 locks held by syz.7.324/8035:
2 locks held by syz.5.325/8037:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
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+0xfd7/0x1030 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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 ae e9 6f 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 ef 5a d9 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 ca 0f f1 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167a28 EFLAGS: 00000202
RAX: 1ffffffff33c8b00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85554e90 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99e45d40 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125d46000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5487507dac CR3: 0000000067254000 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+0x190/0x300 drivers/tty/serial/8250/8250_port.c:1982
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline]
serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x642/0xb50 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