INFO: task syz-executor:5850 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:22280 pid:5850 tgid:5850 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
__schedule_loop kernel/sched/core.c:7049 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7064
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7121
__mutex_lock_common kernel/locking/mutex.c:710 [inline]
__mutex_lock+0x856/0x1420 kernel/locking/mutex.c:794
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1364
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 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:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe12a19d9d7
RSP: 002b:00007ffef3c827e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe12a19d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffef3c828a0
RBP: 00007ffef3c828a0 R08: 00007ffef3c838a0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffef3c83930
R13: 00007fe12a232050 R14: 0000000000107afa R15: 00007ffef3c83970
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e75d0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e75d0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e75d0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5210:
1 lock held by dhcpcd/5505:
#0: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_deladdr+0x23d/0x370 net/ipv6/addrconf.c:4804
2 locks held by getty/5595:
#0: ffff8880376f90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5846:
2 locks held by syz-executor/5850:
#0: ffff8880794800d8 (&type->s_umount_key#129){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880794800d8 (&type->s_umount_key#129){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880794800d8 (&type->s_umount_key#129){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
#1: ffffffff8ea87340 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
2 locks held by syz.5.1848/15369:
#0: ffffffff8fc45888 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ea87340 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670 fs/nfsd/nfsctl.c:1938
2 locks held by kworker/u8:81/17634:
#0: ffff8880b863ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:655
#1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
3 locks held by kworker/u8:85/17655:
#0: ffff8880325a5940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3253 [inline]
#0: ffff8880325a5940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3361
#1: ffffc900051afc40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3254 [inline]
#1: ffffc900051afc40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3361
#2: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4739
3 locks held by kworker/u8:167/17985:
#0: ffff88813fe54140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3253 [inline]
#0: ffff88813fe54140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3361
#1: ffffc90010207c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3254 [inline]
#1: ffffc90010207c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3361
#2: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
8 locks held by kworker/u8:183/18048:
#0: ffff88801bae6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3253 [inline]
#0: ffff88801bae6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3361
#1: ffffc90011067c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3254 [inline]
#1: ffffc90011067c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3361
#2: ffffffff8fbc8a28 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
#3: ffff8880755f8128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:995 [inline]
#3: ffff8880755f8128 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
#3: ffff8880755f8128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:555
#4: ffff888059dad258 (&devlink->lock_key#12){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
#4: ffff888059dad258 (&devlink->lock_key#12){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
#4: ffff888059dad258 (&devlink->lock_key#12){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:555
#5: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x10b/0x730 drivers/net/netdevsim/netdev.c:1129
#6: ffff888039e2cd88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2794 [inline]
#6: ffff888039e2cd88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
#6: ffff888039e2cd88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x118e/0x2370 net/core/dev.c:12431
#7: ffffffff8e7633e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#7: ffffffff8e7633e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
2 locks held by syz-executor/18679:
#0: ffffffff9012bbb8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff9012bbb8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff9012bbb8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8fbd7340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093
=============================================
NMI backtrace for cpu 1
CPU: 1 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 02/12/2026
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: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+0xfd3/0x1030 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12280 Comm: kworker/0:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events free_obj_work
RIP: 0010:__lock_acquire+0x6d5/0x2cf0 kernel/locking/lockdep.c:5207
Code: ba 08 00 00 00 e8 5b 44 00 00 31 ed 85 c0 0f 84 6d 0d 00 00 83 3d 6a 14 87 18 00 75 13 48 63 44 24 18 48 0f a3 05 7b 84 83 12 <0f> 83 8a 1e 00 00 49 8b 9e 40 0b 00 00 48 83 7c 24 28 00 75 19 83
RSP: 0018:ffffc9000d67f2d0 EFLAGS: 00000047
RAX: 0000000000000007 RBX: ffff88807f67e740 RCX: ffffffff93c6b8e8
RDX: 0000000000000008 RSI: ffff88807f67e720 RDI: ffff88807f67db80
RBP: 0000000000000000 R08: ffffffff81771696 R09: ffffffff8e75d0e0
R10: ffffc9000d67f638 R11: fffff52001acfec9 R12: 00000000ffffff05
R13: ffff88807f67e720 R14: ffff88807f67db80 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888125442000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555588b8ea28 CR3: 000000007a87a000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
__unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6242 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6369
free_object_list lib/debugobjects.c:326 [inline]
free_obj_work+0x35c/0x4a0 lib/debugobjects.c:530
process_one_work kernel/workqueue.c:3278 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3361
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3442
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