INFO: task syz.0.2699:13366 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.0.2699 state:D stack:26120 pid:13366 tgid:13362 ppid:12420 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 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+0xccc/0x1bd0 kernel/locking/mutex.c:821
nfsd_nrthreads+0x63/0x1d0 fs/nfsd/nfssvc.c:245
write_threads+0x2e4/0x570 fs/nfsd/nfsctl.c:438
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4c9919e019
RSP: 002b:00007f4c9a0c1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4c99426090 RCX: 00007f4c9919e019
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f4c9923500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4c99426128 R14: 00007f4c99426090 R15: 00007ffe8271ced8
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5371:
#0: ffff888037cc70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
1 lock held by syz.4.914/8120:
2 locks held by syz.2.2190/11437:
#0: ffff88802b5cc0d8 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88802b5cc0d8 (&type->s_umount_key#81){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88802b5cc0d8 (&type->s_umount_key#81){++++}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff88802b5cc0d8 (&type->s_umount_key#81){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
3 locks held by kworker/1:8/11866:
#0: ffff88801bc0f140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc90005417d08 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff8ebf3ca8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
3 locks held by syz.0.2699/13364:
#0: ffff8880311535f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888031d66450 (sb_writers#17){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
3 locks held by syz.0.2699/13366:
#0: ffff8880570a27f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888031d66450 (sb_writers#17){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nrthreads+0x63/0x1d0 fs/nfsd/nfssvc.c:245
1 lock held by syz.8.2959/14065:
#0: ffff88806a144ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497
2 locks held by syz.1.4187/18132:
#0: ffff888037c7c1b0 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_release+0x86/0x1300 drivers/tty/tty_io.c:1727
#1: ffff88803581c2c0 (&port->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#1: ffff88803581c2c0 (&port->mutex){+.+.}-{4:4}, at: tty_port_shutdown+0x24/0x250 drivers/tty/tty_port.c:355
1 lock held by syz.2.4204/18186:
#0: ffff88807eeecea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497
1 lock held by syz.5.4214/18216:
#0: ffffffff8ebf3ca8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 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 lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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: 18216 Comm: syz.5.4214 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:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4855 [inline]
RIP: 0010:__lock_acquire+0x216/0x1a40 kernel/locking/lockdep.c:5187
Code: 8d 04 80 48 8d 04 80 48 8d 04 c5 e0 4d 6b 96 44 0f b6 88 c4 00 00 00 0f b7 43 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 da 6d 85 14 <0f> 83 a3 05 00 00 48 8d 04 80 48 8d 04 80 48 8d 04 c5 e0 4d 6b 96
RSP: 0018:ffffc900050cf448 EFLAGS: 00000003
RAX: 0000000000000007 RBX: ffff888028940ba0 RCX: 0000000000000000
RDX: 0000000000000007 RSI: 0000000000000000 RDI: ffffffff8ebe8200
RBP: ffff888028940000 R08: 0000000000000000 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000007
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000020000
FS: 0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c25727db11 CR3: 000000000e994000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000001 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x162/0x1e0 mm/page_owner.c:165
__reset_page_owner+0x84/0x190 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
free_pages_prepare+0x586/0xd80 mm/page_alloc.c:1451
__free_contig_range_common+0x14f/0x250 mm/page_alloc.c:6897
__free_contig_range mm/page_alloc.c:6942 [inline]
free_pages_bulk+0x12a/0x200 mm/page_alloc.c:5257
vm_area_free_pages+0xad/0x2b0 mm/vmalloc.c:3439
vfree mm/vmalloc.c:3488 [inline]
vfree+0x107/0x750 mm/vmalloc.c:3462
kcov_put kernel/kcov.c:447 [inline]
kcov_put kernel/kcov.c:443 [inline]
kcov_close+0x34/0x60 kernel/kcov.c:554
__fput+0x3ff/0xb50 fs/file_table.c:512
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x951/0x2ae0 kernel/exit.c:1009
do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 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+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f97df79e019
Code: Unable to access opcode bytes at 0x7f97df79dfef.
RSP: 002b:00007ffc4cf6d228 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f97dfa27da0 RCX: 00007f97df79e019
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f97dfa27da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00000000005f1f88 R11: 0000000000000246 R12: 0000000000078d85
R13: 00007f97dfa2609c R14: 0000000000078b29 R15: 00007f97dfa26090