INFO: task syz.6.3204:18006 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.6.3204 state:D stack:28064 pid:18006 tgid:18005 ppid:9254 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 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+0x7fe/0x1300 kernel/locking/mutex.c:776
device_lock include/linux/device.h:895 [inline]
usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
chrdev_open+0x4cd/0x5e0 fs/char_dev.c:414
do_dentry_open+0x7ce/0x1420 fs/open.c:962
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:4637 [inline]
path_openat+0x3486/0x3e20 fs/namei.c:4796
do_filp_open+0x22d/0x490 fs/namei.c:4823
do_sys_openat2+0x12f/0x220 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5df4f5b78e
RSP: 002b:00007f5df5f15b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5df5f166c0 RCX: 00007f5df4f5b78e
RDX: 0000000000000082 RSI: 00007f5df5f15c00 RDI: ffffffffffffff9c
RBP: 00007f5df5f15c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f5df5216038 R14: 00007f5df5215fa0 R15: 00007f5df533fa48
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5588:
#0: ffff8880304fd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
5 locks held by kworker/0:9/10028:
1 lock held by syz.6.3204/18006:
#0: ffff8880288b4198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff8880288b4198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
1 lock held by syz.3.3263/18228:
#0: ffff8880288b4198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff8880288b4198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054
1 lock held by udevd/18935:
1 lock held by syz.2.3609/19645:
#0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:956
1 lock held by syz.7.3614/19661:
2 locks held by syz.7.3614/19663:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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:161 [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:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16846 Comm: kworker/u8:29 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:sched_clock+0x35/0x60 arch/x86/kernel/tsc.c:290
Code: 65 ff 05 6e 8e 88 11 e8 29 b2 2c 0a 48 89 c3 31 f6 65 ff 0d 5d 8e 88 11 40 0f 94 c5 40 0f 94 c6 bf 02 00 00 00 e8 6b 58 5a 00 <40> 84 ed 75 10 e8 61 55 5a 00 48 89 d8 5b 5d c3 cc cc cc cc cc e8
RSP: 0018:ffffc900152575e8 EFLAGS: 00000093
RAX: ffffffff816a21e5 RBX: 000000f77865544a RCX: 0000000000000000
RDX: ffff8880255ddb80 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90015257600 R08: ffffffff819e6cc3 R09: ffff8880b8624588
R10: dffffc0000000000 R11: ffffed1004abbb71 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffc90015257660 R15: 1ffff92002a4aec8
FS: 0000000000000000(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000003cf030 CR3: 000000000e346000 CR4: 00000000003526f0
Call Trace:
sched_clock_cpu+0x74/0x440 kernel/sched/clock.c:397
cpu_clock include/linux/sched/clock.h:93 [inline]
psi_task_switch+0x5b/0x880 kernel/sched/psi.c:934
psi_sched_switch kernel/sched/stats.h:225 [inline]
__schedule+0x24fc/0x5050 kernel/sched/core.c:6861
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
toggle_allocation_gate+0x17c/0x290 mm/kfence/core.c:896
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246