INFO: task syz-executor:13035 blocked for more than 143 seconds.
Tainted: G U 6.15.0-rc6-syzkaller-00025-g627277ba7c23 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:23816 pid:13035 tgid:13035 ppid:1 task_flags:0x400140 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x116f/0x5de0 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6860
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
__mutex_lock_common kernel/locking/mutex.c:678 [inline]
__mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1386
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xde/0x100 fs/super.c:502
cleanup_mnt+0x225/0x450 fs/namespace.c:1431
task_work_run+0x14d/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
do_syscall_64+0xda/0x230 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8b8838fc97
RSP: 002b:00007ffe92c102c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f8b8841089d RCX: 00007f8b8838fc97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe92c10380
RBP: 00007ffe92c10380 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe92c11410
R13: 00007f8b8841089d R14: 00000000000c842e R15: 00007ffe92c11450
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764
2 locks held by kworker/u9:5/5836:
#0: ffff888025aa3148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc90004537d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
2 locks held by syz-executor/13035:
#0: ffff88805c0180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
#0: ffff88805c0180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff88805c0180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff88805c0180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz-executor/14956:
#0: ffff8880237020e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
#0: ffff8880237020e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff8880237020e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff8880237020e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.2.2720/16943:
#0: ffffffff901c97d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xdd/0x1a40 fs/nfsd/nfsctl.c:1923
2 locks held by syz-executor/17184:
#0: ffff88803a3300e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
#0: ffff88803a3300e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff88803a3300e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff88803a3300e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by getty/17620:
#0: ffff8880355110a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000d1bf2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
5 locks held by kworker/u8:3/18277:
#0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc9000acb7d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffffffff90111890 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608
#3: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0x8b/0xaf0 net/core/dev.c:12514
#4: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
3 locks held by kworker/u8:6/18280:
#0: ffff88814d590148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc9000bdbfd18 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4738
2 locks held by kworker/u9:0/18364:
#0: ffff888025b13148 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc90004657d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
2 locks held by syz.6.3280/19284:
#0: ffffffff901c97d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x18a/0x800 fs/nfsd/nfsctl.c:1848
2 locks held by syz-executor/19505:
#0: ffff8880331500e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
#0: ffff8880331500e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff8880331500e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline]
#0: ffff8880331500e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.0.3472/20147:
#0: ffffffff901c97d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629
7 locks held by syz-executor/20442:
#0: ffff8880357e8420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x240 fs/read_write.c:736
#1: ffff888088ad5488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325
#2: ffff888144fec698 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326
#3: ffffffff8f6c9608 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:216
#4: ffff88805ff5a0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
#4: ffff88805ff5a0e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1094 [inline]
#4: ffff88805ff5a0e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1292
#5: ffff88805ff5b250 (&devlink->lock_key#6){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1d0 drivers/net/netdevsim/dev.c:1675
#6: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x280/0x3c0 kernel/rcu/tree_exp.h:304
2 locks held by syz.9.3546/20599:
#0: ffffffff90111890 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514
#1: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1b/0x230 drivers/net/wireguard/device.c:416
1 lock held by syz.8.3548/20619:
#0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline]
#0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390
1 lock held by dhcpcd/20644:
#0: ffff888078e54258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1651 [inline]
#0: ffff888078e54258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3252
1 lock held by dhcpcd/20645:
#0: ffff88808c2ce258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1651 [inline]
#0: ffff88808c2ce258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3252
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U 6.15.0-rc6-syzkaller-00025-g627277ba7c23 #0 PREEMPT(full)
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
watchdog+0xf70/0x12c0 kernel/hung_task.c:437
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245