INFO: task syz.2.1534:12794 blocked for more than 143 seconds. Tainted: G U syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.1534 state:D stack:27688 pid:12794 tgid:12793 ppid:5842 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760 nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1769 genl_family_rcv_msg_doit+0x209/0x2f0 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+0x158/0x420 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2617 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2671 __sys_sendmsg+0x16d/0x220 net/socket.c:2703 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe0f818eec9 RSP: 002b:00007fe0f90b4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe0f83e5fa0 RCX: 00007fe0f818eec9 RDX: 0000000000000844 RSI: 00002000000004c0 RDI: 0000000000000003 RBP: 00007fe0f8211f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe0f83e6038 R14: 00007fe0f83e5fa0 R15: 00007ffdcc134968 Showing all locks held in the system: 3 locks held by kworker/u8:0/12: 4 locks held by rcu_exp_gp_kthr/18: #0: ffff8880b863a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline] #0: ffff8880b863a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629 #1: ffff88807d92a018 (&pid_list->lock){-.-.}-{2:2}, at: trace_pid_list_is_set+0x4c/0x150 kernel/trace/pid_list.c:141 #2: ffff888084cea828 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline] #2: ffff888084cea828 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xb7/0x1870 kernel/sched/core.c:4216 #3: ffff8880b863a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline] #3: ffff8880b863a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629 1 lock held by khungtaskd/31: #0: ffffffff8e1c1fa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e1c1fa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e1c1fa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 4 locks held by kworker/u9:3/5850: #0: ffff888020b94148 ((wq_completion)hci6){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000450fd10 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff8880296acdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 #3: ffff8880296ac0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5677 3 locks held by kworker/0:6/5936: #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000aa07d10 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88806cdb1240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1bb/0x2e80 drivers/net/netdevsim/fib.c:1490 2 locks held by syz.3.828/9569: #0: ffffffff8ff67c90 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629 2 locks held by getty/9667: #0: ffff8880346860a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000379b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 2 locks held by syz.2.1534/12794: #0: ffffffff8ff67c90 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1769 2 locks held by syz.1.1579/12992: #0: ffffffff8ff67c90 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629 2 locks held by syz.4.1694/15141: #0: ffffffff8ff67c90 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b10 fs/nfsd/nfsctl.c:1919 2 locks held by syz.5.1731/15713: #0: ffffffff8ff67c90 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1b10 fs/nfsd/nfsctl.c:1919 2 locks held by syz-executor/16343: #0: ffff888072c960e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888072c960e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888072c960e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888072c960e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz.7.1831/17644: #0: ffff8880854ec0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880854ec0e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880854ec0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff8880854ec0e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e5e02e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 4 locks held by syz-executor/18259: #0: ffff88808b674dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:499 #1: ffff88808b6740b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x3ae/0x11d0 net/bluetooth/hci_sync.c:5289 #2: ffffffff9012ce28 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2115 [inline] #2: ffffffff9012ce28 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x260 net/bluetooth/hci_conn.c:2599 #3: ffff88807f0b9b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1762 3 locks held by kworker/1:4/18843: #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900041f7d10 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff8e1cd538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz.0.1934/19822: #0: ffffffff8e1cd400 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3815 1 lock held by dhcpcd/19850: #0: ffff88804c3e9908 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:979 [inline] #0: ffff88804c3e9908 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:648 2 locks held by dhcpcd/19856: #0: ffff888033402258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline] #0: ffff888033402258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3251 #1: ffffffff8e1cd538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by dhcpcd/19857: #0: ffff88807aefe258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline] #0: ffff88807aefe258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3251 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148 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: 10372 Comm: kworker/u8:8 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:246 Code: cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 07 4d bf 11 <65> 8b 05 18 4d bf 11 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 RSP: 0018:ffffc9000b3e7840 EFLAGS: 00000096 RAX: 0000000000000000 RBX: ffffc9000b3e7990 RCX: ffffffff849c31b2 RDX: ffff88802f999e00 RSI: 0000000000000010 RDI: 0000000000000005 RBP: ffffc9000b3e78b0 R08: 0000000000000005 R09: 0000000000000010 R10: 000000000000000e R11: 00000000f5002331 R12: ffffc9000b3e7ac0 R13: 000000000000000e R14: ffffc9000b3e7a88 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888124e88000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055db0a5f54b0 CR3: 000000000df80000 CR4: 00000000003526f0 Call Trace: chacha_block_generic+0x202/0x330 lib/crypto/chacha-block-generic.c:85 chacha20_block include/crypto/chacha.h:45 [inline] crng_fast_key_erasure+0x19e/0x250 drivers/char/random.c:326 crng_make_state+0x1cc/0x6d0 drivers/char/random.c:392 _get_random_bytes+0x120/0x1e0 drivers/char/random.c:406 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:791 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x798/0xcf0 drivers/net/netdevsim/dev.c:866 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245