INFO: task syz.6.4132:25258 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.4132 state:D stack:26288 pid:25258 tgid:25255 ppid:19234 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d4/0x5630 kernel/sched/core.c:7239 __schedule_loop kernel/sched/core.c:7316 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7331 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7388 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 nfsd_nl_svc_export_get_reqs_dumpit+0xf7/0xc40 fs/nfsd/export.c:674 genl_dumpit+0x10b/0x1b0 net/netlink/genetlink.c:1026 netlink_dump+0x711/0xee0 net/netlink/af_netlink.c:2331 __netlink_dump_start+0x589/0x7b0 net/netlink/af_netlink.c:2446 genl_family_rcv_msg_dumpit+0x213/0x310 net/netlink/genetlink.c:1075 genl_family_rcv_msg net/netlink/genetlink.c:1191 [inline] genl_rcv_msg+0x5e1/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb110d9e0d9 RSP: 002b:00007fb111caf028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb111025fa0 RCX: 00007fb110d9e0d9 RDX: 0000000004044810 RSI: 0000200000000180 RDI: 0000000000000007 RBP: 00007fb110e35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb111026038 R14: 00007fb111025fa0 R15: 00007ffe8ea223b8 Showing all locks held in the system: locks held by ksoftirqd/1/23: 1, last CPU#1: #0: ffff8880b8728198 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:2071 [inline] #0: ffff8880b8728198 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x466/0xa10 kernel/time/hrtimer.c:2124 locks held by khungtaskd/30: 1, last CPU#0: #0: ffffffff8eb5a1e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8eb5a1e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8eb5a1e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6793 locks held by getty/5368: 2, on CPU#0: #0: ffff8880359010a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 locks held by kworker/u8:15/6081: 3, on CPU#0: #0: ffff888032088940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff888032088940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #1: ffffc90005977c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90005977c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #2: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline] #2: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x116/0x15c0 net/ipv6/addrconf.c:4230 locks held by kworker/u8:41/6110: 3, on CPU#0: #0: ffff88801b06c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88801b06c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #1: ffffc90005b07c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90005b07c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #2: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 locks held by kworker/0:5/19819: 3, on CPU#0: #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #1: ffffc90003c6fc40 (netdev_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90003c6fc40 (netdev_work){+.+.}-{0:0}, at: process_scheduled_works+0xa1a/0x14c0 kernel/workqueue.c:3405 #2: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: netdev_work_proc+0x6f/0x770 net/core/netdev_work.c:132 locks held by syz.9.3495/22305: 2, on CPU#0: #0: ffffffff900a70a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ee97420 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x135/0x1750 fs/nfsd/nfsctl.c:1964 locks held by syz.6.4132/25258: 3, on CPU#0: #0: ffffffff900a70a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffff8880337f36e8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2410 #2: ffffffff8ee97420 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_get_reqs_dumpit+0xf7/0xc40 fs/nfsd/export.c:674 locks held by syz.0.4909/28490: 2, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:650 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3587 #1: ffffffff8eb604e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8eb604e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 locks held by syz.8.4912/28505: 1, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:650 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3587 locks held by syz.8.4912/28506: 1, on CPU#1: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:815 locks held by syz.8.4912/28513: 1, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:650 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3587 locks held by syz.8.4912/28520: 1, on CPU#1: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_set_dstaddr+0xee/0x330 net/ipv6/addrconf.c:3009 locks held by syz.1.4917/28524: 1, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4214 locks held by syz.1.4917/28526: 1, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4214 locks held by syz.1.4917/28531: 2, on CPU#1: #0: ffffffff8f7a00c8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f7a00c8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8f7a00c8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:595 #1: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline] #1: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4214 locks held by syz.1.4917/28533: 1, on CPU#1: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x470/0x19f0 net/ipv4/devinet.c:978 locks held by syz.1.4917/28535: 1, on CPU#0: #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline] #0: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4214 locks held by syz.5.4918/28528: 3, on CPU#0: #0: ffffffff900a70a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 #2: ffffffff90036380 (rtnl_mutex){+.+.}-{4:4}, at: wg_set_device_doit+0x170/0x2120 drivers/net/wireguard/netlink.c:484 locks held by syz.2.4919/28537: 2, on CPU#0: #0: ffffffff900a70a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff900a6ee0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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 CPU: 1 UID: 0 PID: 3268 Comm: kworker/u8:10 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline] RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:208 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 e9 90 8d 65 0a cc 89 f6 31 d2 e9 b6 26 9e 03 66 0f 1f 44 00 RSP: 0018:ffffc90000a08d30 EFLAGS: 00000046 RAX: 000000000002ad3d RBX: ffff8880b8723c80 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 000000000002ad3d RDI: 0000000000000838 RBP: ffffc90000a08df0 R08: 0000000000000100 R09: 0000000000080000 R10: 0000000000000000 R11: ffffffff8174c510 R12: 000000000002ad3d R13: dffffc0000000000 R14: 0000000010006657 R15: 0000000000000020 FS: 0000000000000000(0000) GS:ffff888125024000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000032196000 CR4: 00000000003526f0 Call Trace: apic_write arch/x86/include/asm/apic.h:405 [inline] lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:418 clockevents_program_event+0x385/0x630 kernel/time/clockevents.c:372 hrtimer_rearm kernel/time/hrtimer.c:2169 [inline] __hrtimer_rearm_deferred+0x36c/0x4b0 kernel/time/hrtimer.c:2189 hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:58 [inline] hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:67 [inline] irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:505 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:542 [inline] irqentry_exit+0x8d3/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:221 Code: f7 e8 6d 15 c8 f5 f7 c3 00 02 00 00 74 05 e8 70 23 f4 f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 54 37 b9 f5 65 48 8b 05 4c 90 94 07 48 85 c0 74 18 5b 41 5e e9 RSP: 0018:ffffc90000a08f40 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000283 RCX: 8000000000000103 RDX: 0000000000000002 RSI: ffffffff8e257cad RDI: 0000000000000001 RBP: 0000000000000005 R08: ffffffff90589237 R09: 1ffffffff20b1246 R10: dffffc0000000000 R11: fffffbfff20b1247 R12: 0000000000000009 R13: 0000000000000008 R14: ffff8880b8728180 R15: 0000000000000100 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x1b1/0x7a0 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:744 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:801 [inline] nsim_dev_trap_report_work+0x25f/0xb40 drivers/net/netdevsim/dev.c:847 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa88/0x14c0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245