INFO: task syz.4.2843:16069 blocked for more than 143 seconds. Not tainted 6.15.0-rc2-syzkaller-00577-g8066e388be48 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2843 state:D stack:25096 pid:16069 tgid:16068 ppid:5838 task_flags:0x400140 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 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+0x805/0x10c0 kernel/locking/mutex.c:746 nfsd_nl_listener_get_doit+0x115/0x5e0 fs/nfsd/nfsctl.c:2077 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb38/0xf00 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x480 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+0x7f8/0x9a0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:727 ____sys_sendmsg+0x523/0x860 net/socket.c:2566 ___sys_sendmsg net/socket.c:2620 [inline] __sys_sendmsg+0x271/0x360 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f38f698e169 RSP: 002b:00007f38f7809038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f38f6bb5fa0 RCX: 00007f38f698e169 RDX: 0000000000000010 RSI: 0000200000001540 RDI: 0000000000000003 RBP: 00007f38f6a10a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f38f6bb5fa0 R15: 00007ffc2a7740d8 Showing all locks held in the system: 4 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6764 3 locks held by kworker/u8:7/1334: #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9000442fc60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000442fc60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by getty/5595: #0: ffff88803148f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x5bb/0x1700 drivers/tty/n_tty.c:2222 5 locks held by kworker/u8:12/6505: #0: ffff88801bef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801bef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9001bfb7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9001bfb7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff900f1dd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x100/0x940 net/core/net_namespace.c:660 #3: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:174 [inline] #3: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x259/0x8b0 net/core/net_namespace.c:246 #4: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #4: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x384/0x830 kernel/rcu/tree_exp.h:998 3 locks held by kworker/u8:13/6508: #0: ffff88814cfc1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88814cfc1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9001cadfc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9001cadfc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x110/0x16a0 net/ipv6/addrconf.c:4195 2 locks held by syz.0.2800/15925: #0: ffffffff901635d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f0139c8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x135/0x1870 fs/nfsd/nfsctl.c:1923 2 locks held by syz.4.2843/16069: #0: ffffffff901635d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f0139c8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x115/0x5e0 fs/nfsd/nfsctl.c:2077 3 locks held by kworker/1:1/16535: #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9001c36fc60 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9001c36fc60 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 2 locks held by syz.2.3560/18541: #0: ffffffff901635d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f0139c8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x115/0x5e0 fs/nfsd/nfsctl.c:2077 1 lock held by syz.1.3767/19284: #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: do_ipv6_setsockopt+0xa9a/0x35b0 net/ipv6/ipv6_sockglue.c:566 1 lock held by syz.1.3767/19285: #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: do_ipv6_setsockopt+0xa9a/0x35b0 net/ipv6/ipv6_sockglue.c:566 1 lock held by syz.1.3767/19287: #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink+0x3a3/0x8c0 net/core/rtnetlink.c:3556 1 lock held by syz.7.3768/19279: #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3390 2 locks held by syz.7.3768/19283: #0: ffffffff900f1dd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x328/0x570 net/core/net_namespace.c:568 #1: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x1a/0xa0 net/core/dev.c:2081 2 locks held by syz.5.3766/19282: #0: ffffffff901635d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: ethnl_act_cable_test+0x188/0x670 net/ethtool/cabletest.c:75 2 locks held by syz.3.3770/19289: #0: ffffffff900f1dd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x328/0x570 net/core/net_namespace.c:568 #1: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x1a/0xa0 net/core/dev.c:2081 1 lock held by syz-executor/19296: #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff900fe908 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x406/0x1c40 net/ipv4/devinet.c:979 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00577-g8066e388be48 #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+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0x1058/0x10a0 kernel/hung_task.c:437 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/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 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc2-syzkaller-00577-g8066e388be48 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: cc cc cc cc cc cc cc 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 73 8f 1b 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197dc0 EFLAGS: 000002c2 RAX: 096ceb4750e9d400 RBX: ffffffff8197272e RCX: ffffffff8c2ca93c RDX: 0000000000000001 RSI: ffffffff8e646c74 RDI: ffffffff8ca1c5c0 RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2 R13: 1ffff11003ad9b40 R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881250ab000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000003bc030 CR3: 000000000eb38000 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+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x22e/0x5d0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147