INFO: task syz.0.6550:12397 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.0.6550 state:D stack:24800 pid:12397 tgid:12397 ppid:3041 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
device_lock include/linux/device.h:895 [inline]
usbdev_release+0x7e/0x760 drivers/usb/core/devio.c:1099
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a4338f749
RSP: 002b:00007f1a4370fb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f1a435e7da0 RCX: 00007f1a4338f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f1a435e7da0 R08: 0000000000000000 R09: 000000194370fe7f
R10: 00007f1a435e7cb0 R11: 0000000000000246 R12: 00000000001bcf25
R13: 00007f1a435e6090 R14: ffffffffffffffff R15: 00007f1a4370fca0
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5592:
#0: ffff8880325d00a0 (&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+0x449/0x1460 drivers/tty/n_tty.c:2211
6 locks held by kworker/1:14/21729:
2 locks held by kworker/1:5/1771:
1 lock held by syz.0.6550/12397:
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x7e/0x760 drivers/usb/core/devio.c:1099
1 lock held by syz.7.6608/13218:
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
1 lock held by syz.3.6616/13427:
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff88802882d198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
=============================================
NMI backtrace for cpu 0
CPU: 0 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 10/25/2025
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:160 [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+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1771 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 10/25/2025
Workqueue: events dvb_usb_read_remote_control
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:-1 [inline]
RIP: 0010:debug_check_no_obj_freed+0x1f1/0x550 lib/debugobjects.c:1129
Code: 0f 84 44 03 00 00 49 89 ee 49 c1 ee 03 41 80 3c 16 00 74 12 48 89 ef e8 2d 2b 8f fd 48 ba 00 00 00 00 00 fc ff df 48 8b 45 00 <48> 89 04 24 4c 8d 7d 18 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 12 4c
RSP: 0018:ffffc90004bbf698 EFLAGS: 00000046
RAX: ffff88802e4ba690 RBX: 0000000000000005 RCX: dffffc0000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc90004bbf600
RBP: ffff88802de2b6c8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000977ec0 R12: ffff888073658000
R13: ffff888073650000 R14: 1ffff11005bc56d9 R15: ffff88814c85b448
FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01d154f040 CR3: 000000000dd3a000 CR4: 00000000003526f0
DR0: 000000000000b0e1 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
free_pages_prepare mm/page_alloc.c:1413 [inline]
__free_frozen_pages+0x4dd/0xd30 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x146/0x170 mm/slub.c:3886
__slab_free+0x294/0x320 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776
kmalloc_noprof include/linux/slab.h:957 [inline]
usb_control_msg+0x73/0x3e0 drivers/usb/core/message.c:144
m920x_read drivers/media/usb/dvb-usb/m920x.c:36 [inline]
m920x_rc_core_query+0xc0/0x540 drivers/media/usb/dvb-usb/m920x.c:226
dvb_usb_read_remote_control+0xb4/0x1a0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:261
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246