INFO: task syz.3.340:7261 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.340 state:D stack:28424 pid:7261 tgid:7255 ppid:5606 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:293 [inline]
__down_common+0x3b7/0x850 kernel/locking/semaphore.c:318
down+0x80/0xd0 kernel/locking/semaphore.c:100
console_lock+0x58/0x90 kernel/printk/printk.c:2896
class_console_lock_constructor include/linux/console.h:734 [inline]
vcs_open+0x61/0xd0 drivers/tty/vt/vc_screen.c:746
chrdev_open+0x4d9/0x600 fs/char_dev.c:411
do_dentry_open+0x816/0x1380 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2e44/0x3830 fs/namei.c:4863
do_file_open+0x23e/0x4a0 fs/namei.c:4892
do_sys_openat2+0x115/0x200 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1385
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: 0033:0x7f8804d9e0d9
RSP: 002b:00007f8805c94028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8805026180 RCX: 00007f8804d9e0d9
RDX: 0000000000002000 RSI: 00002000000001c0 RDI: ffffffffffffff9c
RBP: 00007f8804e35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8805026218 R14: 00007f8805026180 R15: 00007ffc2e467cd8
INFO: task syz.3.340:7262 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.340 state:D stack:28424 pid:7262 tgid:7255 ppid:5606 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
tty_open+0x204/0xcc0 drivers/tty/tty_io.c:2120
chrdev_open+0x4d9/0x600 fs/char_dev.c:411
do_dentry_open+0x816/0x1380 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2e44/0x3830 fs/namei.c:4863
do_file_open+0x23e/0x4a0 fs/namei.c:4892
do_sys_openat2+0x115/0x200 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1385
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: 0033:0x7f8804d5e90e
RSP: 002b:00007f8805c72b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8805c736c0 RCX: 00007f8804d5e90e
RDX: 0000000000000002 RSI: 00007f8805c72c00 RDI: ffffffffffffff9c
RBP: 00007f8804e35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8805026308 R14: 00007f8805026270 R15: 00007ffc2e467cd8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by klogd/4959:
3 locks held by udevd/4970:
2 locks held by getty/5359:
#0: ffff888035c910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
5 locks held by kworker/0:8/5886:
#0: ffff888022ec5140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff888022ec5140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900048ffc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900048ffc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff8880297a41d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff8880297a41d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5899
#3: ffff88804ffb21d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff88804ffb21d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#4: ffff88807c2ab1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff88807c2ab1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
4 locks held by udevd/5900:
#0: ffff88808a8ea1b8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0 fs/seq_file.c:183
#1: ffff88803fb4c080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165
#2: ffff88803fb533c8 (kn->active#29){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88803fb533c8 (kn->active#29){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166
#3: ffff88804ffb21d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1107 [inline]
#3: ffff88804ffb21d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by kworker/u8:10/5907:
#0: ffff88801b064140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801b064140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90004bdfc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90004bdfc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
4 locks held by syz.1.308/7137:
1 lock held by syz.3.340/7262:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0 drivers/tty/tty_io.c:2120
2 locks held by kworker/u8:13/7356:
#0: ffff88801e77c940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801e77c940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90004ed7c40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90004ed7c40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
1 lock held by syz.2.415/7594:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0 drivers/tty/tty_io.c:2120
1 lock held by syz.0.418/7602:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0 drivers/tty/tty_io.c:2120
1 lock held by syz.4.431/7674:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0 drivers/tty/pty.c:800
1 lock held by syz.6.433/7684:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0 drivers/tty/tty_io.c:2120
4 locks held by syz-executor/7707:
2 locks held by syz-executor/7737:
1 lock held by syz.7.464/7897:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0 drivers/tty/pty.c:800
1 lock held by syz.5.466/7914:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0 drivers/tty/pty.c:800
1 lock held by syz.3.535/8298:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0 drivers/tty/pty.c:800
2 locks held by syz.9.539/8313:
#0: ffff88803385c518 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0 fs/seq_file.c:183
#1: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: t_start+0x1b/0x50 fs/proc/proc_tty.c:106
1 lock held by syz.1.550/8392:
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffffffff8f457d80 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0 drivers/tty/pty.c:800
1 lock held by modprobe/8455:
1 lock held by syz-executor/8456:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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