INFO: task syz.0.290:8520 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.290 state:D stack:28656 pid:8520 tgid:8519 ppid:8101 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1665 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1742 [inline]
__rt_mutex_slowlock_locked+0x1f36/0x2550 kernel/locking/rtmutex.c:1782
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1822
__rt_mutex_lock kernel/locking/rtmutex.c:1837 [inline]
rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:245
__super_lock fs/super.c:58 [inline]
super_lock+0x289/0x3d0 fs/super.c:122
super_lock_excl fs/super.c:147 [inline]
grab_super+0xb9/0x380 fs/super.c:533
sget_fc+0x2c2/0xa40 fs/super.c:804
sget_dev fs/super.c:1408 [inline]
get_tree_bdev_flags+0x214/0x4f0 fs/super.c:1680
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4383 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4360
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: 0033:0x7f25e9a5ce59
RSP: 002b:00007f25e7cae028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f25e9cd5fa0 RCX: 00007f25e9a5ce59
RDX: 0000200000000040 RSI: 0000200000000000 RDI: 0000200000000180
RBP: 00007f25e9af2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000080c80e R11: 0000000000000246 R12: 0000000000000000
R13: 0000[ 580.282759][ T38] R13: 00007f25e9cd6038 R14: 00007f25e9cd5fa0 R15: 00007ffcffcba088
</TASK>
Showing all locks held in the system:
2 locks held by kworker/0:1/10:
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc900000f7c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc900000f7c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:6/153:
#0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000398fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000398fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffffffff8f3417e0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
#3: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: fib6_rules_net_exit_batch+0x20/0xc0 net/ipv6/fib6_rules.c:644
1 lock held by udevd/4978:
#0: ffff8880110e6480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
2 locks held by getty/5366:
#0: ffff8880379560a0 (&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+0x462/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by syz-executor/5615:
3 locks held by kworker/1:5/5732:
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc9000568fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc9000568fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
#2: ffff88803b077280 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
2 locks held by kworker/0:6/5804:
#0: ffff88801dae2d38 ((wq_completion)inet_frag_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801dae2d38 ((wq_completion)inet_frag_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90005977c40 ((work_completion)(&fqdir->destroy_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90005977c40 ((work_completion)(&fqdir->destroy_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
1 lock held by syz.0.290/8520:
#0: ffff8880371080d0 (&type->s_umount_key#83){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880371080d0 (&type->s_umount_key#83){+.+.}-{4:4}, at: super_lock+0x289/0x3d0 fs/super.c:122
2 locks held by syz-executor/9210:
1 lock held by syz-executor/9341:
1 lock held by syz-executor/9353:
#0: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978
7 locks held by syz-executor/9442:
#0: ffff88801196a480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff88801196a480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88806488a878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff888029ab5968 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888029ab5968 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8ebd4c78 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
#4: ffff888039fbd160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
#4: ffff888039fbd160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1076
#5: ffff888037bb6310 (&devlink->lock_key#27){+.+.}-{4:4}, at: nsim_drv_probe+0xc9/0xc30 drivers/net/netdevsim/dev.c:1658
#6: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1057 [inline]
#6: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: nsim_create+0x894/0x1170 drivers/net/netdevsim/netdev.c:1151
1 lock held by syz-executor/9705:
#0: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f350538 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109
1 lock held by dhcpcd-run-hook/9800:
2 locks held by syz-executor/9801:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
<TASK>
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: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+0xfd3/0x1030 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
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 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 04/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 2e 1b 90 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 4f 48 f7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 4a 0b eb 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff3360d00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99b06bb0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85345110 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b06920 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126187000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42274dd020 CR3: 0000000050bb4000 CR4: 00000000003526f0
Call Trace:
<TASK>
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1973
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3210 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3275 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3360
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 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
</TASK>