INFO: task syz.0.600:8044 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.0.600 state:D stack:28552 pid:8044 tgid:8041 ppid:5605 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
nfsd_nrthreads+0x5b/0x320 fs/nfsd/nfssvc.c:245
write_threads+0x1fe/0x5a0 fs/nfsd/nfsctl.c:438
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
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: 0033:0x7f53ced9e0d9
RSP: 002b:00007f53cfbac028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f53cf026090 RCX: 00007f53ced9e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f53cee35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f53cf026128 R14: 00007f53cf026090 R15: 00007ffd8db929e8
Showing all locks held in the system:
6 locks held by kworker/1:0/24:
#0: ffff88801ead8140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801ead8140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc900001e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc900001e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffff8880296581d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff8880296581d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5907
#3: ffff88807c82b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff88807c82b1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#4: ffff88807bf391a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88807bf391a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#5: ffffffff8e9f5a48 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xfc/0x2c0 kernel/umh.c:212
1 lock held by khungtaskd/31:
#0: ffffffff8eb59d60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eb59d60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8eb59d60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/0:2/1544:
2 locks held by getty/5363:
#0: ffff88803252d0a0 (&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
2 locks held by syz-executor/5606:
#0: ffff888078fb80e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888078fb80e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888078fb80e8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
1 lock held by syz-executor/5617:
#0: ffff8880b863b360 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:675
2 locks held by syz-executor/5620:
#0: ffff88807a2f60e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88807a2f60e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88807a2f60e8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
3 locks held by syz.0.600/8042:
#0: ffff888032b00630 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88807dfde460 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
#1: ffff88807dfde460 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860
3 locks held by syz.0.600/8044:
#0: ffff88807a9c07f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88807dfde460 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2739 [inline]
#1: ffff88807dfde460 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nrthreads+0x5b/0x320 fs/nfsd/nfssvc.c:245
2 locks held by syz-executor/8192:
#0: ffff88803e1b60e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88803e1b60e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88803e1b60e8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/8943:
#0: ffff88807f7d20e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88807f7d20e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88807f7d20e8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
1 lock held by syz-executor/9677:
#0: ffffffff8eb60068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#0: ffffffff8eb60068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
2 locks held by syz.4.984/9742:
#0: ffff888068a740e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888068a740e8 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888068a740e8 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8ee8f560 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
1 lock held by syz.8.1028/9907:
#0: ffff8880681e0ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:497 [inline]
#0: ffff8880681e0ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x22a/0x5b0 net/bluetooth/hci_core.c:2678
1 lock held by syz.1.1032/9916:
#0: ffff88802a988ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:497 [inline]
#0: ffff88802a988ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x22a/0x5b0 net/bluetooth/hci_core.c:2678
=============================================
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 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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9677 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:kasan_byte_accessible+0x16/0x30 mm/kasan/generic.c:212
Code: 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df 0f b6 04 07 <3c> 08 0f 92 c0 e9 6b a9 db fe cc 66 66 66 66 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc9000301f768 EFLAGS: 00000216
RAX: 0000000000000000 RBX: ffffffff82405649 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff82405649 RDI: 1ffffffff1d6b3ac
RBP: ffffffff8240562c R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100f838cd6 R12: 0000000000000002
R13: ffffffff8eb59d60 R14: ffffffff8eb59d60 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812503f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055db2642eee8 CR3: 000000000e946000 CR4: 0000000000350ef0
Call Trace:
__kasan_check_byte+0x12/0x40 mm/kasan/common.c:573
kasan_check_byte include/linux/kasan.h:402 [inline]
lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5842
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
__page_table_check_zero+0x89/0x430 mm/page_table_check.c:138
page_table_check_free include/linux/page_table_check.h:46 [inline]
__free_pages_prepare mm/page_alloc.c:1407 [inline]
free_pages_prepare+0x96f/0xa60 mm/page_alloc.c:1451
__free_contig_range_common+0x174/0x340 mm/page_alloc.c:6897
__free_contig_range mm/page_alloc.c:6942 [inline]
free_pages_bulk+0x48/0x120 mm/page_alloc.c:5257
vm_area_free_pages mm/vmalloc.c:3461 [inline]
vfree+0x224/0x4a0 mm/vmalloc.c:3510
kcov_put kernel/kcov.c:449 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:554
__fput+0x418/0xa50 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x73a/0x2360 kernel/exit.c:1009
do_group_exit+0x22d/0x2f0 kernel/exit.c:1152
get_signal+0x121b/0x12c0 kernel/signal.c:3046
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x104/0x750 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f213e95e90e
Code: Unable to access opcode bytes at 0x7f213e95e8e4.
RSP: 002b:00007ffc4ca870d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000020 RBX: 000055557618f500 RCX: 00007f213e95e90e
RDX: 0000000000000020 RSI: 00007f213f754670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffc4ca87154 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffc4ca871bc R14: 00007f213f754670 R15: 0000000000000000