INFO: task syz.3.2222:12967 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.2222 state:D stack:23784 pid:12967 ppid:5784 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 perf_pending_task_sync kernel/events/core.c:5244 [inline] _free_event+0x174/0xf30 kernel/events/core.c:5250 put_event kernel/events/core.c:5378 [inline] perf_event_release_kernel+0x842/0x8d0 kernel/events/core.c:5503 perf_release+0x3b/0x40 kernel/events/core.c:5513 __fput+0x234/0x970 fs/file_table.c:384 task_work_run+0x1d4/0x260 kernel/task_work.c:245 get_signal+0x1235/0x13f0 kernel/signal.c:2678 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe4d439ce59 RSP: 002b:00007fe4d52d8fd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffff RBX: 00007fe4d4616090 RCX: 00007fe4d439ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000002c9a4080 RBP: 00007fe4d4432d6f R08: ffffffffff600000 R09: ffffffffff600000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fe4d4616128 R14: 00007fe4d4616090 R15: 00007ffdd85e0888 Showing all locks held in the system: 1 lock held by rcu_tasks_trace/15: #0: ffff8880b8e3c098 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 1 lock held by khungtaskd/29: #0: ffffffff8d132160 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d132160 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d132160 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5533: #0: ffff88802cd250a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 3 locks held by kworker/u4:14/8304: 2 locks held by kworker/0:8/12407: #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc900040a7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900040a7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 5 locks held by kworker/u4:69/13046: #0: ffff88801a254938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff88801a254938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc900037f7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900037f7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #2: ffffffff8e3b9990 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x14c/0xbb0 net/core/net_namespace.c:606 #3: ffffffff8e3c6988 (rtnl_mutex){+.+.}-{3:3}, at: ip6_tnl_exit_batch_net+0xcc/0x630 net/ipv6/ip6_tunnel.c:2297 #4: ffffffff8d137b38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #4: ffffffff8d137b38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 2 locks held by kworker/u4:70/13048: #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc9000337fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc9000337fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 3 locks held by kworker/u4:71/13049: #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc90003807d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc90003807d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #2: ffffffff8d137b38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #2: ffffffff8d137b38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by syz.1.2754/15070: 1 lock held by syz.4.2763/15089: #0: ffffffff8d188368 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 1 lock held by syz.0.2765/15093: #0: ffffffff8d188368 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 1 lock held by syz.0.2765/15094: #0: ffffffff8e3c6988 (rtnl_mutex){+.+.}-{3:3}, at: arp_ioctl+0x26f/0x530 net/ipv4/arp.c:1239 2 locks held by syz.0.2765/15101: #0: ffffffff8e3ab8c8 (br_ioctl_mutex){+.+.}-{3:3}, at: br_ioctl_call net/socket.c:1190 [inline] #0: ffffffff8e3ab8c8 (br_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x4f4/0x7e0 net/socket.c:1294 #1: ffffffff8e3c6988 (rtnl_mutex){+.+.}-{3:3}, at: br_ioctl_stub+0x1a9/0xd50 net/bridge/br_ioctl.c:418 2 locks held by syz.1.2766/15097: #0: ffffffff97323c30 (&pmus_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:116 [inline] #0: ffffffff97323c30 (&pmus_srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:215 [inline] #0: ffffffff97323c30 (&pmus_srcu){.+.+}-{0:0}, at: perf_init_event kernel/events/core.c:11890 [inline] #0: ffffffff97323c30 (&pmus_srcu){.+.+}-{0:0}, at: perf_event_alloc+0xc06/0x21b0 kernel/events/core.c:12211 #1: ffffffff8d188368 (event_mutex){+.+.}-{3:3}, at: perf_trace_init+0x50/0x2d0 kernel/trace/trace_event_perf.c:221 1 lock held by syz.1.2766/15100: #0: ffffffff8d188368 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf3d/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 13048 Comm: kworker/u4:70 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: bat_events batadv_nc_worker RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x84c/0x8c0 kernel/locking/lockdep.c:5765 Code: e8 89 b1 76 00 48 8b 1d fa 9a 0d 0d 48 85 db 74 33 48 83 c3 08 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 5a b1 76 00 48 8b 3b 48 8b 74 24 18 4c 89 f2 e8 RSP: 0018:ffffc9000337f980 EFLAGS: 00000246 RAX: 1ffff11003b64433 RBX: ffff88801db22198 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8b6668 RBP: ffffc9000337faa0 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd R10: dffffc0000000000 R11: fffffbfff1d16cce R12: ffffffff8a501c41 R13: dffffc0000000000 R14: ffffffff8a501c41 R15: 1ffff9200066ff3c FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2ed05a CR3: 00000000469a9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000b6e DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:165 [inline] _raw_spin_unlock_bh+0x1b/0x40 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_nc_purge_paths+0x311/0x3a0 net/batman-adv/network-coding.c:471 batadv_nc_worker+0x328/0x610 net/batman-adv/network-coding.c:720 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293