INFO: task syz.5.2496:17191 blocked for more than 143 seconds. Not tainted 6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.2496 state:D stack:28280 pid:17191 tgid:17189 ppid:8973 task_flags:0x400140 flags:0x00000004 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_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 genl_family_rcv_msg_doit+0x206/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16d/0x440 net/netlink/af_netlink.c:2534 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc9e418e969 RSP: 002b:00007fc9e502f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fc9e43b5fa0 RCX: 00007fc9e418e969 RDX: 0000000020004080 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007fc9e4210ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc9e43b5fa0 R15: 00007ffdc186ca98 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/u9:1/5142: #0: ffff8880264cb148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000f57fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 3 locks held by kworker/1:3/5873: 3 locks held by kworker/1:5/5901: #0: ffff88801b480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90004ab7d18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 3 locks held by kworker/u10:9/15925: #0: ffff88801b489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000b517d18 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff9012a528 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303 2 locks held by syz-executor/16471: #0: ffff888023be40e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888023be40e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888023be40e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888023be40e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz-executor/16718: #0: ffff8880308da0e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880308da0e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880308da0e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff8880308da0e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz.0.2437/16910: #0: ffffffff901cc650 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz-executor/17109: #0: ffff888051dc60e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888051dc60e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888051dc60e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888051dc60e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz.5.2496/17191: #0: ffffffff901cc650 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz-executor/17418: #0: ffff8880346100e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880346100e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880346100e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff8880346100e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz-executor/17533: #0: ffff88805d6420e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805d6420e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805d6420e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff88805d6420e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz-executor/18236: #0: ffff88802a9bc0e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88802a9bc0e0 (&type->s_umount_key#49){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88802a9bc0e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff88802a9bc0e0 (&type->s_umount_key#49){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7ceea8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by getty/18285: #0: ffff888035efa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900032002f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 5 locks held by syz-executor/18527: #0: ffff888096cc4d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:481 #1: ffff888096cc4078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5213 #2: ffffffff90397f68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2065 [inline] #2: ffffffff90397f68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x260 net/bluetooth/hci_conn.c:2534 #3: ffff88804c63d338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1762 #4: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x280/0x3c0 kernel/rcu/tree_exp.h:304 1 lock held by syz.9.2828/19447: #0: ffffffff9012a528 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff9012a528 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 PREEMPT(full) 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+0x3c2/0x780 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81 Code: f6 64 02 e9 83 fc 02 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 4f 20 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007e10 EFLAGS: 000002c2 RAX: 0000000000401d43 RBX: 0000000000000000 RCX: ffffffff8b69a3e9 RDX: 0000000000000000 RSI: ffffffff8dbde4a7 RDI: ffffffff8bf48c60 RBP: fffffbfff1c12ee8 R08: 0000000000000001 R09: ffffed10170865bd R10: ffff8880b8432deb R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e097740 R14: ffffffff90854c10 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000073c000 CR3: 000000000e180000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:743 start_kernel+0x3e9/0x4d0 init/main.c:1099 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x148