INFO: task syz.4.47:6171 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.47 state:D stack:28064 pid:6171 tgid:6170 ppid:5801 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 svc_listen+0x2c3/0x500 net/atm/svc.c:311 __sys_listen_socket net/socket.c:1987 [inline] __sys_listen net/socket.c:2002 [inline] __do_sys_listen net/socket.c:2007 [inline] __se_sys_listen net/socket.c:2005 [inline] __x64_sys_listen+0x1c7/0x240 net/socket.c:2005 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f180319ce59 RSP: 002b:00007f1803fae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000032 RAX: ffffffffffffffda RBX: 00007f1803415fa0 RCX: 00007f180319ce59 RDX: 0000000000000000 RSI: 0000000000000081 RDI: 0000000000000004 RBP: 00007f1803232d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1803416038 R14: 00007f1803415fa0 R15: 00007ffcb1ce4738 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:3/48: #0: ffff888032715140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff888032715140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90000b87c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90000b87c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4206 5 locks held by kworker/u8:8/1106: #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801be8e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90005507c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90005507c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdc1668 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673 #3: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0x9e0 net/core/dev.c:13078 #4: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #4: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 3 locks held by kworker/u8:9/1343: #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff88801ae84140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90005c17c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90005c17c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 2 locks held by getty/5381: #0: ffff888032cd10a0 (&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+0x45c/0x13a0 drivers/tty/n_tty.c:2211 1 lock held by syz.4.47/6171: #0: ffff888021a98260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff888021a98260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.2.466/8103: #0: ffff8880290a7260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff8880290a7260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.5.662/9027: #0: ffff8880586db260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff8880586db260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.0.757/9459: #0: ffff888032f29260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff888032f29260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.1.879/10064: #0: ffff8880594a8260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff8880594a8260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.6.928/10307: #0: ffff88807bc37260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff88807bc37260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz.7.982/10553: #0: ffff88802c8ae260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff88802c8ae260 (sk_lock-AF_ATMSVC){+.+.}-{0:0}, at: svc_listen+0x13f/0x500 net/atm/svc.c:295 1 lock held by syz-executor/10731: #0: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 2 locks held by syz.8.1043/10886: #0: ffffffff8fdc1668 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz.9.1044/10887: #0: ffffffff8fdc1668 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 2 locks held by syz.3.1045/10893: #0: ffffffff8fdc1668 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575 #1: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8fdd0340 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x1a/0xa0 net/core/dev.c:2102 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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:162 [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+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 145 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:unwind_next_frame+0x497/0x2550 arch/x86/kernel/unwind_orc.c:520 Code: 3b 02 00 00 4c 8d 62 04 4c 8d 6a 05 4c 89 e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 c2 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 <84> c0 0f 85 d5 19 00 00 41 0f b6 44 24 01 83 e0 07 0f 84 75 16 00 RSP: 0018:ffffc90002f6f4b8 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: ffffffff9048c688 RCX: ffffffff9048c68c RDX: ffffffff90c4472e RSI: ffffffff90c4472e RDI: ffffffff8c28ad80 RBP: dffffc0000000000 R08: 0000000000000007 R09: ffffffff8e95cd60 R10: ffffc90002f6f638 R11: fffff520005edec9 R12: ffffffff90c44732 R13: ffffffff90c44733 R14: ffffc90002f6f5e8 R15: ffffffff9048c688 FS: 0000000000000000(0000) GS:ffff888125286000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb452fea540 CR3: 000000005bdf2000 CR4: 00000000003526f0 Call Trace: __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6250 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6377 nsim_dev_trap_report drivers/net/netdevsim/dev.c:892 [inline] nsim_dev_trap_report_work+0x7de/0xb90 drivers/net/netdevsim/dev.c:922 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 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