INFO: task syz.3.2953:11748 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2953 stat[ 524.947132][ T38] task:syz.3.2953 state:D stack:28424 pid:11748 tgid:11746 ppid:5783 task_flags:0x400040 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]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
device_lock include/linux/device.h:1102 [inline]
usbdev_open+0x151/0x790 drivers/usb/core/devio.c:1054
chrdev_open+0x4dc/0x600 fs/char_dev.c:411
do_dentry_open+0x849/0x1420 fs/open.c:947
vfs_open+0x3b/0x350 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2e60/0x3850 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: 0033:0x7f1a7f5fe68e
RSP: 002b:00007f1a7d895b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1a7d8966c0 RCX: 00007f1a7f5fe68e
RDX: 0000000000101301 RSI: 00007f1a7d895c00 RDI: ffffffffffffff9c
RBP: 00007f1a7d895c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f1a7f8c6038 R14: 00007f1a7f8c5fa0 R15: 00007ffc0746a498
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/4962:
2 locks held by getty/5348:
#0: ffff8880368db0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
10 locks held by syz-executor/5782:
5 locks held by kworker/1:5/5892:
3 locks held by kworker/1:7/5907:
6 locks held by udevd/6227:
1 lock held by syz.3.2953/11748:
#0: ffff888029e2e210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#0: ffff888029e2e210 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x790 drivers/usb/core/devio.c:1054
9 locks held by syz-executor/12094:
1 lock held by syz.1.3227/12329:
#0: ffff888029e2e210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#0: ffff888029e2e210 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x790 drivers/usb/core/devio.c:1054
1 lock held by syz.4.4421/14941:
1 lock held by syz.6.4425/14948:
2 locks held by syz.2.4426/14949:
=============================================
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 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 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 05/09/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x80 kernel/kcov.c:216
Code: 8b 3d e4 57 ee 0b 48 89 de 5b e9 a3 04 5e 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 88 37 d8 10 65 8b 35 a9 37 d8 10 81 e6 00 00 ff 00 ba
RSP: 0018:ffffc90000007a80 EFLAGS: 00000046
RAX: ffffffff8149551e RBX: ffffffff99acf8a8 RCX: ffff88801caedd00
RDX: ffffffff99acf8a8 RSI: 0000000000000000 RDI: ffffffff8df78580
RBP: 00000000ffffffff R08: 0000000000010000 R09: 0000000000010000
R10: dffffc0000000000 R11: ffffffff81495500 R12: dffffc0000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffffffff1bef0b0
FS: 0000000000000000(0000) GS:ffff888125c49000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2cd20000 CR3: 000000002c320000 CR4: 00000000003526f0
Call Trace:
pvclock_gtod_notify+0x1e/0x4b0 arch/x86/kvm/x86.c:9966
notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
update_pvclock_gtod kernel/time/timekeeping.c:662 [inline]
timekeeping_update_from_shadow+0x79f/0xb10 kernel/time/timekeeping.c:816
__timekeeping_advance+0xc37/0x10a0 kernel/time/timekeeping.c:2614
timekeeping_advance kernel/time/timekeeping.c:2622 [inline]
update_wall_time+0x31/0x1a0 kernel/time/timekeeping.c:2632
tick_sched_do_timer kernel/time/tick-sched.c:253 [inline]
tick_nohz_handler+0xee/0x6b0 kernel/time/tick-sched.c:310
__run_hrtimer kernel/time/hrtimer.c:2032 [inline]
__hrtimer_run_queues+0x3a0/0xaf0 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x44a/0x900 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x2a/0xa0 kernel/kcov.c:300
Code: f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 38 34 d8 10 65 44 8b 05 58 34 d8 10 41 81 e0 00 00 ff 00 ba 00 01 00 00 23 91 f4 0b 00 00 <41> 89 d1 45 09 c1 74 12 45 85 c0 75 5f 85 d2 74 5b 83 b9 0c 17 00
RSP: 0018:ffffc90000167a68 EFLAGS: 00000246
RAX: ffffffff855520ca RBX: 0000000000000020 RCX: ffff88801caedd00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85552080 R12: dffffc0000000000
R13: ffffffff99e42cc0 R14: ffffffff99e42cc0 R15: 0000000000000000
io_serial_out+0x4a/0xc0 drivers/tty/serial/8250/8250_port.c:406
serial_port_out include/linux/serial_core.h:813 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3239 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x1201/0x1b40 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