INFO: task syz.4.2981:16418 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2981 state:D stack:28472 pid:16418 tgid:16417 ppid:15517 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
__schedule_loop kernel/sched/core.c:7049 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7064
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7121
__mutex_lock_common kernel/locking/mutex.c:710 [inline]
__mutex_lock+0x856/0x1420 kernel/locking/mutex.c:794
bdev_open+0xe0/0xd30 block/bdev.c:953
bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1067
setup_bdev_super+0x5a/0x5b0 fs/super.c:1612
get_tree_bdev_flags+0x389/0x4f0 fs/super.c:1692
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:4399 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4376
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f280839c819
RSP: 002b:00007f280919d028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2808615fa0 RCX: 00007f280839c819
RDX: 0000200000001300 RSI: 00002000000012c0 RDI: 0000200000000300
RBP: 00007f2808432c91 R08: 00002000000035c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2808616038 R14: 00007f2808615fa0 R15: 00007ffd736ff5a8
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:3/49:
#0: ffff8880b873ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
#1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
#2: ffff8880b8726118 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x8ee/0xf30 kernel/time/timer.c:1117
1 lock held by klogd/5200:
#0: ffff8880b873ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
2 locks held by getty/5594:
#0: ffff888036dc00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by kworker/1:4/5906:
#0: ffff8880226ae540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff8880226ae540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc90004277c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc90004277c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffff888029ee21d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:995 [inline]
#2: ffff888029ee21d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
#3: ffff8880628e21d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:995 [inline]
#3: ffff8880628e21d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
1 lock held by udevd/6349:
#0: ffff8880270c2350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953
4 locks held by udevd/6351:
#0: ffff888022f31bd8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183
#1: ffff88805cafb480 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2: ffff88805a80c1e8 (kn->active#31){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88805a80c1e8 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff8880628e21d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1000 [inline]
#3: ffff8880628e21d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by syz.4.2981/16418:
#0: ffff888031c020d8 (&type->s_umount_key#70/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:345
#1: ffff8880270c2350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:953
1 lock held by syz.2.3681/19236:
#0: ffffffff8e963438 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
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: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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16064 Comm: kworker/1:5 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:wq_watchdog_touch+0xb4/0x160 kernel/workqueue.c:7825
Code: d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 c2 a3 a0 00 49 c7 c6 88 02 42 93 4c 03 33 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 92 a4 a0 00 49 89 2e eb 18 e8 c8 3a 37 00 48 8d
RSP: 0018:ffffc90003526f80 EFLAGS: 00000046
RAX: 1ffff110170e4851 RBX: ffffffff8e3c7798 RCX: 0000000000100000
RDX: ffffc900173c1000 RSI: 0000000000050526 RDI: 0000000000050527
RBP: 000000010000bc05 R08: ffff888025ec0237 R09: 1ffff11004bd8046
R10: dffffc0000000000 R11: ffffffff8bb91670 R12: 00000000000036b0
R13: 000000010000b05c R14: ffff8880b8724288 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125304000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000430 CR3: 00000000629e6000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
touch_nmi_watchdog include/linux/nmi.h:151 [inline]
wait_for_lsr+0x16a/0x2f0 drivers/tty/serial/8250/8250_port.c:1977
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x1348/0x1ba0 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
dev_vprintk_emit+0x355/0x420 drivers/base/core.c:4916
dev_printk_emit+0xee/0x140 drivers/base/core.c:4927
_dev_info+0x11e/0x180 drivers/base/core.c:4985
usb_disconnect+0xdd/0x990 drivers/usb/core/hub.c:2327
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x1cc9/0x4f30 drivers/usb/core/hub.c:5953
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
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