INFO: task syz.3.75:6197 blocked for more than 143 seconds. Not tainted 6.14.0-syzkaller-09584-g7d06015d936c #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.75 state:D stack:28432 pid:6197 tgid:6194 ppid:5835 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:664 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:732 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+0x16a/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/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f672fd8d169 RSP: 002b:00007f6730c05038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f672ffa6080 RCX: 00007f672fd8d169 RDX: 0000000000040010 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f672fe0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f672ffa6080 R15: 00007ffe9a0d7428 Showing all locks held in the system: 4 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8e3bdcc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3bdcc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3bdcc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6761 2 locks held by kworker/u8:4/68: #0: ffff88801c3be948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90001567d18 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 2 locks held by syz-executor/5836: #0: ffff888030b420e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888030b420e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888030b420e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888030b420e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz-executor/5840: #0: ffff888045f620e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888045f620e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888045f620e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888045f620e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 3 locks held by kworker/1:3/5843: #0: ffff88801b480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc900040cfd18 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff8e3c90c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3774 2 locks held by syz.3.75/6195: #0: ffffffff901c12d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz.3.75/6197: #0: ffffffff901c12d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 4 locks held by kworker/u8:10/6213: #0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000b987d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90109810 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 #3: ffffffff8e3c91f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x280/0x3c0 kernel/rcu/tree_exp.h:304 2 locks held by syz.0.226/6892: #0: ffffffff901c12d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz.5.467/8042: #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 1 lock held by syz.5.467/8045: #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88802619a0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: super_lock+0x17d/0x3f0 fs/super.c:120 2 locks held by syz-executor/8310: #0: ffff88802975c0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88802975c0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88802975c0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff88802975c0e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7c2628 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 3 locks held by kworker/u8:32/8745: #0: ffff8880b8439f18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:605 #1: ffff8880b8423c48 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2c1/0x8e0 kernel/sched/psi.c:987 #2: ffffffff9adc5168 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x14c/0x4c0 lib/debugobjects.c:818 5 locks held by syz.7.624/8912: #0: ffff888034d9cd80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:481 #1: ffff888034d9c078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5213 #2: ffffffff9038e888 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2066 [inline] #2: ffffffff9038e888 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x260 net/bluetooth/hci_conn.c:2701 #3: ffff8880a128db38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1761 #4: ffffffff8e3c91f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 2 locks held by getty/8918: #0: ffff8880369620a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000c05b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfa1/0x1450 drivers/tty/n_tty.c:2211 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-syzkaller-09584-g7d06015d936c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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:236 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:399 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:111