INFO: task syz.1.636:6794 blocked for more than 146 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.636 state:D stack:27920 pid:6794 ppid:4276 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
nfsd_svc+0x61/0xab0 fs/nfsd/nfssvc.c:783
write_threads+0x2ea/0x350 fs/nfsd/nfsctl.c:424
nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f186619de99
RSP: 002b:00007f1866f81028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1866426090 RCX: 00007f186619de99
RDX: 0000000000000002 RSI: 0000200000000400 RDI: 0000000000000008
RBP: 00007f1866233eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1866426128 R14: 00007f1866426090 R15: 00007ffef62a2798
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
5 locks held by kworker/u4:4/57:
#0: ffff88801761e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90001587d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd4ead0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
#3: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xd2/0x370 net/ipv4/ip_tunnel.c:1152
#4: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#4: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
3 locks held by kworker/0:3/2172:
2 locks held by dhcpcd/3935:
#0: ffffffff8ddbc170 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860
#1: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x5a/0x890 net/wireless/nl80211.c:16372
2 locks held by getty/4038:
#0: ffff88814cf96098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by kworker/0:5/4320:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003d97d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/0:6/4321:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900042e7d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
3 locks held by syz.1.636/6789:
#0: ffff88802c7a6868 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff88807efe6460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdcce08 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:846
3 locks held by syz.1.636/6794:
#0: ffff88807d307768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff88807efe6460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffffffff8cdcce08 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_svc+0x61/0xab0 fs/nfsd/nfssvc.c:783
3 locks held by kworker/u4:21/6877:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000593fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
1 lock held by syz-executor/7806:
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.2.924/7946:
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495
1 lock held by syz.5.931/7983:
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495
3 locks held by syz.4.933/7990:
#0: ffff88805c7c14b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline]
#0: ffff88805c7c14b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20e/0x500 net/bluetooth/hci_core.c:2733
#1: ffff88805c7c0428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x506/0x1120 net/bluetooth/hci_sync.c:5271
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1834 [inline]
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2532
3 locks held by syz.0.932/7989:
#0: ffff88805c7bd4b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline]
#0: ffff88805c7bd4b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20e/0x500 net/bluetooth/hci_core.c:2733
#1: ffff88805c7bc428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x506/0x1120 net/bluetooth/hci_sync.c:5271
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1834 [inline]
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2532
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7806 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:unwind_next_frame+0x9b/0x1fd0 arch/x86/kernel/unwind_orc.c:436
Code: 24 17 00 00 89 44 24 64 48 89 6c 24 40 4c 89 6c 24 68 4c 89 64 24 48 4c 89 7c 24 10 bf 01 00 00 00 e8 09 c1 1f 00 4c 8d 7b 50 <4c> 89 f8 48 c1 e8 03 48 89 44 24 30 42 80 3c 30 00 74 08 4c 89 ff
RSP: 0018:ffffc90004def120 EFLAGS: 00000246
RAX: 1ffff1100fb4dddb RBX: ffffc90004def1c8 RCX: ffffffff96c16100
RDX: dffffc0000000000 RSI: ffffffff81c377b5 RDI: ffffffff8138fb37
RBP: 1ffff920009bde40 R08: ffffc90004def290 R09: 0000000000000003
R10: dffffc0000000000 R11: fffff520009bde45 R12: ffffffff81c377b5
R13: ffffc90004def6b8 R14: dffffc0000000000 R15: ffffc90004def218
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055accfb04000 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
save_stack+0x121/0x230 mm/page_owner.c:127
__reset_page_owner+0x51/0x190 mm/page_owner.c:148
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1487 [inline]
free_pcp_prepare mm/page_alloc.c:1537 [inline]
free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3555
release_pages+0x20d1/0x2340 mm/swap.c:1035
tlb_batch_pages_flush mm/mmu_gather.c:60 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:255 [inline]
tlb_flush_mmu+0x105/0x220 mm/mmu_gather.c:262
tlb_finish_mmu+0xf0/0x220 mm/mmu_gather.c:394
exit_mmap+0x388/0x970 mm/mmap.c:3262
__mmput+0x118/0x3a0 kernel/fork.c:1206
exit_mm+0x24d/0x350 kernel/exit.c:566
do_exit+0x958/0x2570 kernel/exit.c:868
do_group_exit+0x229/0x2e0 kernel/exit.c:1024
get_signal+0x1259/0x1340 kernel/signal.c:2872
arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f06fa15e6ce
Code: Unable to access opcode bytes at 0x7f06fa15e6a4.
RSP: 002b:00007fff204c98e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000060 RBX: 000055558151e500 RCX: 00007f06fa15e6ce
RDX: 0000000000000060 RSI: 00007f06faf54670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007fff204c9964 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f06faf54670 R15: 0000000000000000