INFO: task syz.0.3810:22458 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3810 state:D stack:27704 pid:22458 tgid:22445 ppid:15272 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:6964
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
fdget_pos+0x2aa/0x380 fs/file.c:1255
class_fd_pos_constructor include/linux/file.h:85 [inline]
ksys_write+0x71/0x250 fs/read_write.c:729
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f129439acb9
RSP: 002b:00007f12951ca028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1294616360 RCX: 00007f129439acb9
RDX: 0000000000000004 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007f1294408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f12946163f8 R14: 00007f1294616360 R15: 00007ffe0448e5e8
Showing all locks held in the system:
1 lock held by kthreadd/2:
1 lock held by khungtaskd/31:
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e5e31a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
1 lock held by kcompactd0/34:
3 locks held by kworker/u8:3/50:
3 locks held by kworker/u8:5/80:
3 locks held by kworker/u8:7/1104:
#0: ffff88814d083148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc90003f9fc98 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734
4 locks held by kworker/u8:8/1164:
6 locks held by kworker/u8:9/2115:
3 locks held by kworker/u8:13/3513:
3 locks held by kworker/u8:14/3563:
4 locks held by kworker/u8:15/3742:
4 locks held by kworker/u8:19/4587:
1 lock held by klogd/5196:
2 locks held by udevd/5207:
1 lock held by dhcpcd/5502:
3 locks held by crond/5581:
2 locks held by getty/5599:
#0: ffff8880315490a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5825:
2 locks held by kworker/0:6/5928:
3 locks held by kworker/u8:2/10768:
3 locks held by kworker/u8:4/11709:
2 locks held by kworker/u8:21/11711:
3 locks held by kworker/u8:25/11715:
3 locks held by kworker/u8:26/11716:
3 locks held by kworker/0:7/14296:
#0: ffff88813fe15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc90003567c98 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
3 locks held by kworker/u8:28/14848:
3 locks held by kworker/u8:29/14849:
1 lock held by syz-executor/15272:
1 lock held by syz-executor/15429:
2 locks held by syz.0.2886/18472:
3 locks held by kworker/u8:32/19320:
3 locks held by kworker/u8:33/19321:
#0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc9000bc17c98 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303
4 locks held by kworker/u8:34/19322:
3 locks held by kworker/0:8/20417:
#0: ffff88813fe16948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc9000e66fc98 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x91/0x10e0 net/wireless/reg.c:2453
2 locks held by kworker/0:10/21174:
2 locks held by syz.3.3809/22442:
10 locks held by syz.0.3810/22449:
#0: ffff888034f8cb78 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1255
#1: ffff888031ac0420 (sb_writers#7){.+.+}-{0:0}, at: do_writev+0x13e/0x340 fs/read_write.c:1103
#2: ffff888068aeac88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343
#3: ffff888143742a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#3: ffff888143742a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344
#4: ffffffff8f94fe08 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234
#5: ffff888035bb30e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#5: ffff888035bb30e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1104 [inline]
#5: ffff888035bb30e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1302
#6: ffff88807a8a7250 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1e0 drivers/net/netdevsim/dev.c:1778
#7: ffffffff903f45e8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x108/0x830 drivers/net/netdevsim/netdev.c:1175
#8: ffff88803568cd38 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2781 [inline]
#8: ffff88803568cd38 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
#8: ffff88803568cd38 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline]
#8: ffff88803568cd38 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0xd49/0x2580 net/core/dev.c:12383
#9: ffffffff8e5ef978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
4 locks held by syz.0.3810/22453:
1 lock held by syz.0.3810/22458:
#0: ffff888034f8cb78 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1255
2 locks held by syz.2.3814/22464:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
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:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246