INFO: task syz.0.371:7376 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.371 state:D stack:26128 pid:7376 tgid:7369 ppid:5829 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14ef/0x4fb0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x164/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 nfsd_nl_rpc_status_get_dumpit+0xdc/0x1410 fs/nfsd/nfsctl.c:1483 genl_dumpit+0x10b/0x1b0 net/netlink/genetlink.c:1027 netlink_dump+0x722/0xe80 net/netlink/af_netlink.c:2325 __netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2440 genl_family_rcv_msg_dumpit+0x213/0x310 net/netlink/genetlink.c:1076 genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline] genl_rcv_msg+0x5e8/0x7a0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x4d7/0x810 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f33f979acb9 RSP: 002b:00007f33fa6f1028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f33f9a16180 RCX: 00007f33f979acb9 RDX: 0000000000000800 RSI: 0000200000000180 RDI: 0000000000000007 RBP: 00007f33f9808bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f33f9a16218 R14: 00007f33f9a16180 R15: 00007ffe1d5b8298 Showing all locks held in the system: 4 locks held by kworker/u8:0/12: #0: ffff88801b29f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801b29f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90000117bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90000117bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8f799ed0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670 #3: ffffffff8e360c38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #3: ffffffff8e360c38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:956 1 lock held by khungtaskd/31: #0: ffffffff8e35a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e35a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e35a320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:3/38: #0: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 #1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 #2: ffff8880b86260d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1004 [inline] #2: ffff8880b86260d8 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30 kernel/time/timer.c:1085 3 locks held by kworker/u8:9/2119: #0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88813fe29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90004c27bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90004c27bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by klogd/5188: #0: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 #1: ffffffff8e490ba0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 1 lock held by dhcpcd/5494: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120 2 locks held by getty/5589: #0: ffff88814dd810a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 2 locks held by syz.1.83/6279: #0: ffffffff8f8169f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e678968 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x16c0 fs/nfsd/nfsctl.c:1886 3 locks held by syz.0.371/7376: #0: ffffffff8f8169f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffff88804ff9d6f0 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2404 #2: ffffffff8e678968 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xdc/0x1410 fs/nfsd/nfsctl.c:1483 2 locks held by syz.2.870/9296: #0: ffffffff8f8169f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e678968 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x16c0 fs/nfsd/nfsctl.c:1886 2 locks held by syz.5.1737/13138: #0: ffffffff8f799ed0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cb/0x570 net/core/net_namespace.c:577 #1: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d7/0x840 net/ipv4/ip_tunnel.c:1146 1 lock held by syz.3.1747/13186: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 1 lock held by syz.3.1747/13190: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120 2 locks held by syz.6.1749/13201: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:6964 #1: ffffffff8e360c38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8e360c38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:956 1 lock held by syz.6.1749/13205: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 1 lock held by syz.4.1750/13207: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3bc/0x1e10 drivers/net/tun.c:3078 1 lock held by syz.4.1750/13214: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:6964 1 lock held by syz.4.1750/13215: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 1 lock held by syz.4.1750/13216: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:813 1 lock held by syz.4.1750/13217: #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:6964 3 locks held by syz.4.1750/13218: #0: ffffffff8f8169f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f816808 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8f816808 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8f816808 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1209 #2: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: __tipc_nl_compat_doit net/tipc/netlink_compat.c:358 [inline] #2: ffffffff8f7a8848 (rtnl_mutex){+.+.}-{4:4}, at: tipc_nl_compat_doit+0x22a/0x650 net/tipc/netlink_compat.c:393 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 945 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: 0x0 (events_long) RIP: 0010:match_held_lock+0x2/0xb0 kernel/locking/lockdep.c:5305 Code: 0f b9 3a 90 31 db 48 89 d8 5b 41 5e 41 5f c3 cc cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 56 <53> bb 01 00 00 00 48 39 77 10 74 6a 81 7f 20 00 00 20 00 72 5f 48 RSP: 0018:ffffc900038e7bf8 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffff8880b863a098 RDI: ffff888025db8b30 RBP: ffff888025db8b30 R08: ffff88802579c927 R09: 0000000000000000 R10: ffff88802579c910 R11: ffffed1004af3925 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880b863a098 R15: ffff888025db8000 FS: 0000000000000000(0000) GS:ffff888125929000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555a47b4e8 CR3: 0000000031f1c000 CR4: 00000000003526f0 Call Trace: find_held_lock kernel/locking/lockdep.c:5350 [inline] __lock_release kernel/locking/lockdep.c:5535 [inline] lock_release+0x10c/0x3a0 kernel/locking/lockdep.c:5889 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:157 [inline] _raw_spin_unlock_irq+0x16/0x50 kernel/locking/spinlock.c:202 worker_thread+0xa7c/0xd90 kernel/workqueue.c:3435 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246