INFO: task kworker/u8:11:1193 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/u8:11 state:D stack:21224 pid:1193 tgid:1193 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[ 565.129107][ T38] __schedule_loop kernel/sched/core.c:7311 [inline]
schedule[ 565.129107][ T38] 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:5603 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:22512 pid:5603 tgid:5603 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: 0033:0x7f42c53fe097
RSP: 002b:00007fffca856848 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f42c54922ca RCX: 00007f42c53fe097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffca856900
RBP: 00007fffca856900 R08: 00007fffca857900 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffca857990
R13: 00007f42c54922ca R14: 0000000000064572 R15: 00007fffca8579d0
Showing all locks held in the system:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:2/43:
4 locks held by kworker/u8:6/124:
#0: ffff88801b2a8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801b2a8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90002f4fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90002f4fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8f362b20 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673
#3: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: wg_destruct+0x25/0x310 drivers/net/wireguard/device.c:246
3 locks held by kworker/u8:9/1134:
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90006087c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90006087c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by kworker/u8:11/1193:
#0: ffff88801f6cf938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801f6cf938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900061d7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900061d7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
2 locks held by getty/5353:
#0: ffff88803687c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cb62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5603:
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
3 locks held by kworker/u9:5/5619:
#0: ffff88805f9cb938 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88805f9cb938 ((wq_completion)hci0){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900051efc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900051efc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff888062254f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1cb/0x3f0 net/bluetooth/hci_sync.c:331
1 lock held by udevd/5830:
6 locks held by kworker/u8:0/9499:
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc9000422fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000422fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff888065166310 (&devlink->lock_key#6){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xcb0 drivers/net/netdevsim/dev.c:909
#3: ffff8880384fd120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#3: ffff8880384fd120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:862 [inline]
#3: ffff8880384fd120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1e0/0xcb0 drivers/net/netdevsim/dev.c:922
#4: ffff8880384fd0e0 (_T->lock){....}-{2:2}, at: rt_mutex_slowunlock+0xbf/0xa20 kernel/locking/rtmutex.c:1430
#5: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#5: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
#5: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
3 locks held by kworker/u8:1/9637:
#0: ffff888031e88938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888031e88938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc9000409fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc9000409fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4229
7 locks held by syz-executor/9751:
#0: ffff888036056500 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#0: ffff888036056500 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#1: ffff88803b81f878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
#2: ffff88802985da58 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88802985da58 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
#3: ffffffff8ebe7118 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
#4: ffff888040ada160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff888040ada160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#5: ffff888061eec310 (&devlink->lock_key#12){+.+.}-{4:4}, at: nsim_drv_probe+0xfc/0xc00 drivers/net/netdevsim/dev.c:1658
#6: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#6: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2163
4 locks held by syz-executor/9987:
#0: ffff888036056500 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#0: ffff888036056500 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#1: ffff888036bee478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
#2: ffff88802985da58 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88802985da58 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
#3: ffffffff8ebe7118 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
1 lock held by syz.5.816/10039:
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
1 lock held by syz-executor/10226:
#0: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
1 lock held by poweroff/10254:
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880289380d0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
5 locks held by kworker/u8:14/10261:
2 locks held by syz-executor/10348:
#0: ffffffff8f362b20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575
#1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8f3716b8 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11553
7 locks held by syz-executor/10409:
5 locks held by syz.9.840/10462:
#0: ffff8880623cc0d0 (&type->s_umount_key#28/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline]
#0: ffff8880623cc0d0 (&type->s_umount_key#28/1){+.+.}-{4:4}, at: sget_fc+0x938/0x1910 fs/super.c:766
#1: ffff888035f303c0 (&sbi->s_error_notify_mutex){+.+.}-{4:4}, at: ext4_register_sysfs+0x91/0x2d0 fs/ext4/sysfs.c:616
#2: ffff8880b883a208 ((lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff8880b883a208 ((lock)){+.+.}-{3:3}, at: __radix_tree_preload+0x141/0x870 lib/radix-tree.c:334
#3: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#3: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffff88801a08f100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#4: ffff88801a08f100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: __kernfs_new_node+0x11e/0xa70 fs/kernfs/dir.c:670
1 lock held by cmp/10466:
=============================================
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 de 9a 89 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 1f ff f2 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167a28 EFLAGS: 00000202
RAX: 1ffffffff336f500 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff853b8d20 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b7aaa0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126211000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b21507286 CR3: 000000003276c000 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:3229 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3294 [inline]
serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3379
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