syzbot

INFO: task syz-executor:5629 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-executor    state:D stack:22232 pid:5629  tgid:5629  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
 deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
 deactivate_super fs/super.c:509 [inline]
 deactivate_super+0xe7/0x110 fs/super.c:505
 cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
 task_work_run+0x150/0x240 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+0x107/0x4f0 kernel/entry/common.c:98
 __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+0x6f2/0x830 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb6db39e097
RSP: 002b:00007ffd56f97f78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fb6db4321ca RCX: 00007fb6db39e097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd56f98030
RBP: 00007ffd56f98030 R08: 00007ffd56f99030 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd56f990c0
R13: 00007fb6db4321ca R14: 0000000000048537 R15: 00007ffd56f99100
 </TASK>
INFO: task syz-executor:5630 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23384 pid:5630  tgid:5630  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
 deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
 deactivate_super fs/super.c:509 [inline]
 deactivate_super+0xe7/0x110 fs/super.c:505
 cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
 task_work_run+0x150/0x240 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+0x107/0x4f0 kernel/entry/common.c:98
 __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+0x6f2/0x830 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5920f9e097
RSP: 002b:00007ffd32d70188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f59210321ca RCX: 00007f5920f9e097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd32d70240
RBP: 00007ffd32d70240 R08: 00007ffd32d71240 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd32d712d0
R13: 00007f59210321ca R14: 0000000000048526 R15: 00007ffd32d71310
 </TASK>
INFO: task syz-executor:9265 blocked for more than 146 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:24088 pid:9265  tgid:9265  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
 deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
 deactivate_super fs/super.c:509 [inline]
 deactivate_super+0xe7/0x110 fs/super.c:505
 cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
 task_work_run+0x150/0x240 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+0x107/0x4f0 kernel/entry/common.c:98
 __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+0x6f2/0x830 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa5f39e097
RSP: 002b:00007ffffb2b1808 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007ffa5f4321ca RCX: 00007ffa5f39e097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffffb2b18c0
RBP: 00007ffffb2b18c0 R08: 00007ffffb2b28c0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffffb2b2950
R13: 00007ffa5f4321ca R14: 000000000004a7ed R15: 00007ffffb2b2990
 </TASK>
INFO: task syz.2.748:9783 blocked for more than 147 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.748       state:D stack:26904 pid:9783  tgid:9777  ppid:5628   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1938
 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
 __sys_sendmsg+0x170/0x220 net/socket.c:2784
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x830 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3aa339ce59
RSP: 002b:00007f3aa427a028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3aa3616090 RCX: 00007f3aa339ce59
RDX: 0000000020000000 RSI: 0000200000000140 RDI: 0000000000000002
RBP: 00007f3aa3432d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3aa3616128 R14: 00007f3aa3616090 R15: 00007fff2f063e38
 </TASK>
INFO: task syz.2.748:9787 blocked for more than 148 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.748       state:D stack:27528 pid:9787  tgid:9777  ppid:5628   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820
 nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1938
 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
 __sys_sendmsg+0x170/0x220 net/socket.c:2784
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x830 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3aa339ce59
RSP: 002b:00007f3aa4259028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3aa3616180 RCX: 00007f3aa339ce59
RDX: 0000000020008050 RSI: 00002000000050c0 RDI: 0000000000000002
RBP: 00007f3aa3432d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3aa3616218 R14: 00007f3aa3616180 R15: 00007fff2f063e38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e7e5420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e7e5420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8e7e5420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by syz-executor/5629:
 #0: ffff888076be00d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888076be00d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888076be00d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff888076be00d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/5630:
 #0: ffff88807a51a0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88807a51a0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88807a51a0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff88807a51a0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by getty/7389:
 #0: ffff8880374d90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000545b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:35/8084:
 #0: ffff88813fe9c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: ffffc90003c6fd08 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
 #2: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:313
6 locks held by kworker/u8:36/8085:
 #0: ffff88801c6ae140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
 #1: ffffc90003c7fd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
 #2: ffffffff905f8b88 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673
 #3: ffff88802d477128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
 #3: ffff88802d477128 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
 #3: ffff88802d477128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x19e/0x370 net/devlink/core.c:555
 #4: ffff88802d474258 (&devlink->lock_key#16){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
 #4: ffff88802d474258 (&devlink->lock_key#16){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
 #4: ffff88802d474258 (&devlink->lock_key#16){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x1b4/0x370 net/devlink/core.c:555
 #5: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #5: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2162
2 locks held by syz.0.595/8961:
 #0: ffffffff906bfe08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1938
2 locks held by syz-executor/9265:
 #0: ffff888059ff60d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888059ff60d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888059ff60d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff888059ff60d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.2.748/9783:
 #0: ffffffff906bfe08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1938
2 locks held by syz.2.748/9787:
 #0: ffffffff906bfe08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1938
2 locks held by syz-executor/10211:
 #0: ffff88807c4700d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88807c4700d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88807c4700d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff88807c4700d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/10212:
 #0: ffff88805484e0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88805484e0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88805484e0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff88805484e0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/10342:
 #0: ffff88807bb560d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88807bb560d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88807bb560d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff88807bb560d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/10856:
 #0: ffff888058c5c0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888058c5c0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888058c5c0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff888058c5c0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.5.917/10906:
 #0: ffff8880588ea0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880588ea0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880588ea0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff8880588ea0d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/10960:
 #0: ffff8880569b40d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880569b40d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880569b40d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff8880569b40d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/11121:
 #0: ffff8880365a80d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880365a80d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880365a80d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff8880365a80d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
1 lock held by syz.3.988/11436:
2 locks held by syz-executor/11600:
 #0: ffff88802a3140d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88802a3140d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88802a3140d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
 #0: ffff88802a3140d8 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.2.1061/11914:
 #0: ffffffff906bfe08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8ec62380 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x8ec/0x12b0 fs/nfsd/nfsctl.c:1633
1 lock held by syz.0.1115/12211:
1 lock held by syz-executor/12251:
 #0: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
 #0: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3438
1 lock held by syz.7.1125/12259:
 #0: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
 #0: ffffffff906118e0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3438

=============================================

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 04/18/2026
Call Trace:
 <TASK>
 __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:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+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
 </TASK>