INFO: task syz-executor:5826 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:23448 pid:5826 tgid:5826 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe6/0x5fa0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0xdd/0x390 kernel/sched/core.c:6964 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1353 deactivate_locked_super+0xc1/0x1b0 fs/super.c:474 deactivate_super fs/super.c:507 [inline] deactivate_super+0xe7/0x110 fs/super.c:503 cleanup_mnt+0x21f/0x450 fs/namespace.c:1318 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:44 [inline] exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x4ea/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fabe0d9c117 RSP: 002b:00007ffdfe996068 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fabe0e0471f RCX: 00007fabe0d9c117 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdfe996120 RBP: 00007ffdfe996120 R08: 00007ffdfe997120 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdfe9971b0 R13: 00007fabe0e0471f R14: 0000000000073f49 R15: 00007ffdfe9971f0 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e5e3120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 2 locks held by syz-executor/5826: #0: ffff8880763880e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880763880e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880763880e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff8880763880e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503 #1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz.4.1786/13795: #0: ffffffff904a2bd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596 2 locks held by getty/14934: #0: ffff88814d70c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000432c2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 3 locks held by kworker/u10:4/15075: #0: ffff88801c29f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232 #1: ffffc9000b26fc98 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233 #2: ffffffff903dd430 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xab/0x830 net/core/net_namespace.c:670 3 locks held by kworker/u11:1/15099: #0: ffff8880426e1948 ((wq_completion)hci6){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232 #1: ffffc90004cafc98 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233 #2: ffff88805846cec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x18a/0x470 net/bluetooth/hci_sync.c:331 2 locks held by syz.0.2123/15153: #0: ffffffff904a2bd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c6/0x7a0 fs/nfsd/nfsctl.c:1678 2 locks held by syz.5.2148/15240: #0: ffff8880434e1908 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #0: ffff8880434e1908 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661 #1: ffffffff904a0470 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain kernel/notifier.c:379 [inline] #1: ffffffff904a0470 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x53/0xa0 kernel/notifier.c:368 2 locks held by syz-executor/15416: #0: ffff888029fb00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888029fb00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888029fb00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888029fb00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:503 #1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575 2 locks held by syz.1.2229/15583: #0: ffffffff903dd430 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:577 #1: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816 2 locks held by syz.1.2229/15585: #0: ffffffff903dd430 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:577 #1: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816 3 locks held by syz.8.2237/15607: #0: ffff8880596dccc8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #0: ffff8880596dccc8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661 #1: ffffffff904a0470 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain kernel/notifier.c:379 [inline] #1: ffffffff904a0470 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x53/0xa0 kernel/notifier.c:368 #2: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816 2 locks held by syz.9.2273/15719: #0: ffffffff904a2bd0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ea476a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b20 fs/nfsd/nfsctl.c:1886 7 locks held by syz-executor/15722: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff888032cc5488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 #4: ffff8880317570e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff8880317570e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline] #4: ffff8880317570e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1304 #5: ffff888035158250 (&devlink->lock_key){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1e0 drivers/net/netdevsim/dev.c:1778 #6: ffffffff8e5ef7c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3816 4 locks held by syz-executor/15786: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff888029b58888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15795: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff88808a1f4c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15804: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff888041fadc88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15819: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff88807afb4888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15831: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff88807ec1fc88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15840: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff8880680c7c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/15849: #0: ffff888033e9a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #1: ffff88809c666c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888027c00b48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8f950288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 ============================================= 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 01/24/2026 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:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline] watchdog+0xcc3/0xfe0 kernel/hung_task.c:515 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246