INFO: task syz.1.2312:17197 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.1.2312 state:D stack:27848 pid:17197 tgid:17192 ppid:5630 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_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1365 deactivate_locked_super+0xc1/0x1b0 fs/super.c:477 deactivate_super fs/super.c:510 [inline] deactivate_super+0xe7/0x110 fs/super.c:506 cleanup_mnt+0x21f/0x450 fs/namespace.c:1317 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:70 [inline] exit_to_user_mode_loop+0x1d8/0x6f0 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+0x652/0x840 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f68f4f9de59 RSP: 002b:00007f68f5ea7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: fffffffffffffffe RBX: 00007f68f5226090 RCX: 00007f68f4f9de59 RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 0000000000000000 RBP: 00007f68f5033e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f68f5226128 R14: 00007f68f5226090 R15: 00007ffc7c676798 INFO: task syz.1.2312:17198 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.1.2312 state:D stack:28856 pid:17198 tgid:17192 ppid:5630 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 rwsem_down_write_slowpath+0x4c2/0x12b0 kernel/locking/rwsem.c:1215 __down_write_common kernel/locking/rwsem.c:1347 [inline] __down_write kernel/locking/rwsem.c:1356 [inline] down_write+0x1c7/0x1f0 kernel/locking/rwsem.c:1632 __super_lock fs/super.c:58 [inline] super_lock+0x1ca/0x3f0 fs/super.c:122 super_lock_excl fs/super.c:147 [inline] grab_super fs/super.c:534 [inline] sget_fc+0x10dd/0x1d80 fs/super.c:806 vfs_get_super fs/super.c:1262 [inline] get_tree_keyed+0x59/0x1d0 fs/super.c:1304 vfs_get_tree+0x92/0x320 fs/super.c:1694 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount fs/namespace.c:3841 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4161 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount fs/namespace.c:4367 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4367 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f68f4f9de59 RSP: 002b:00007f68f5e86028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f68f5226180 RCX: 00007f68f4f9de59 RDX: 0000200000000180 RSI: 00002000000000c0 RDI: 0000000000000000 RBP: 00007f68f5033e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f68f5226218 R14: 00007f68f5226180 R15: 00007ffc7c676798 INFO: task syz.0.2315:17259 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.0.2315 state:D stack:26440 pid:17259 tgid:17257 ppid:16823 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_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1365 deactivate_locked_super+0xc1/0x1b0 fs/super.c:477 vfs_get_super fs/super.c:1278 [inline] get_tree_keyed+0x18a/0x1d0 fs/super.c:1304 vfs_get_tree+0x92/0x320 fs/super.c:1694 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount fs/namespace.c:3841 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4161 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount fs/namespace.c:4367 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4367 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4d7439de59 RSP: 002b:00007f4d751fd028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f4d74625fa0 RCX: 00007f4d7439de59 RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 0000000000000000 RBP: 00007f4d74433e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4d74626038 R14: 00007f4d74625fa0 R15: 00007ffc9c953b78 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8ebe5f00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8ebe5f00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8ebe5f00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 2 locks held by getty/5381: #0: ffff8880332380a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5631: #0: ffff8880424de0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880424de0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880424de0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff8880424de0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.3.2306/17143: #0: ffffffff90b4c928 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1a80 fs/nfsd/nfsctl.c:1964 2 locks held by syz.1.2312/17197: #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 1 lock held by syz.1.2312/17198: #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880582f80d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: super_lock+0x1ca/0x3f0 fs/super.c:122 2 locks held by syz.0.2315/17259: #0: ffff888056c080d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff888056c080d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/17292: #0: ffff8880341bc0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880341bc0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880341bc0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff8880341bc0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/17343: #0: ffff88802a3460d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a3460d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88802a3460d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88802a3460d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/17383: #0: ffff88807b9960d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807b9960d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88807b9960d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88807b9960d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/17435: #0: ffff88802e6680d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802e6680d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88802e6680d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88802e6680d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/17685: #0: ffff88807ad8a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807ad8a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88807ad8a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88807ad8a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.9.2412/17997: #0: ffff88807a0620d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff88807a0620d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.3.2418/18025: #0: ffff8880352a60d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff8880352a60d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.1.2420/18033: #0: ffff888065bd20d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff888065bd20d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.0.2404/18052: #0: ffff88802a1560d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff88802a1560d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/18055: #0: ffff8880783580d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880783580d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880783580d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff8880783580d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor/18076: #0: ffff88807ba9a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807ba9a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88807ba9a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88807ba9a0d8 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz.4.2431/18259: #0: ffff8880a069e0d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff8880a069e0d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 3 locks held by syz.7.2437/18291: #0: ffff88805a69cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497 #1: ffff88805a69c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x37e/0x13c0 net/bluetooth/hci_sync.c:5393 #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2148 [inline] #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2733 3 locks held by syz-executor/18422: #0: ffff88814ab48ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497 #1: ffff88814ab480b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x37e/0x13c0 net/bluetooth/hci_sync.c:5393 #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2148 [inline] #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2733 5 locks held by syz-executor/18458: #0: ffff88809a4acea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497 #1: ffff88809a4ac0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x37e/0x13c0 net/bluetooth/hci_sync.c:5393 #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2148 [inline] #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2733 #3: ffff8880a1e12af8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x95/0x710 net/bluetooth/l2cap_core.c:1778 #4: ffffffff8ebf19a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 2 locks held by syz.6.2463/18491: #0: ffff8880355da0d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline] #0: ffff8880355da0d8 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: sget_fc+0x3c8/0x1d80 fs/super.c:766 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 3 locks held by syz-executor/18637: #0: ffff88803d818ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:497 #1: ffff88803d8180b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x37e/0x13c0 net/bluetooth/hci_sync.c:5393 #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2148 [inline] #2: ffffffff90d28c20 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2733 2 locks held by syz.8.2481/18646: #0: ffffffff90b4c928 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8f06f260 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x8c8/0x1100 fs/nfsd/nfsctl.c:1660 ============================================= 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 05/09/2026 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