INFO: task syz.7.3421:14192 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.3421 state:D stack:23088 pid:14192 ppid:10135 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 perf_pending_task_sync kernel/events/core.c:5031 [inline] _free_event+0x171/0x10a0 kernel/events/core.c:5037 put_event kernel/events/core.c:5162 [inline] perf_event_release_kernel+0x83e/0x8d0 kernel/events/core.c:5287 perf_release+0x37/0x40 kernel/events/core.c:5297 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x11a6/0x1350 kernel/signal.c:2648 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871 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:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5710f9c799 RSP: 002b:00007f5711eddfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffffc RBX: 00007f5711215fa0 RCX: 00007f5710f9c799 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000640c7000 RBP: 00007f5711032c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f5711216038 R14: 00007f5711215fa0 R15: 00007fffed227b18 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2dfb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2e7d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 3 locks held by kworker/u4:2/32: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90000a8fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 1 lock held by dhcpcd/3932: #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6147 2 locks held by getty/4033: #0: ffff88814d39e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198 5 locks held by kworker/u4:8/4553: 3 locks held by kworker/u4:9/8717: #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538 #1: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: do_perf_sw_event kernel/events/core.c:9706 [inline] #1: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: ___perf_sw_event+0x180/0x6e0 kernel/events/core.c:9744 #2: ffff8880b8e28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999 2 locks held by kworker/0:6/12287: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc900035cfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 1 lock held by syz.9.4477/17895: #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: bpf_xdp_link_release+0x7b/0x4c0 net/core/dev.c:9427 2 locks held by syz.5.4480/17905: #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3492 #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 2 locks held by syz.6.4488/17929: #0: ffffffff8cb826a8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239 #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #1: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 1 lock held by syz.6.4488/17930: #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x54d/0xe80 net/core/dev_ioctl.c:571 2 locks held by syz.6.4488/17934: #0: ffffffff8dd2c848 (br_ioctl_mutex){+.+.}-{3:3}, at: br_ioctl_call net/socket.c:1173 [inline] #0: ffffffff8dd2c848 (br_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x475/0x710 net/socket.c:1274 #1: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: br_ioctl_stub+0x1ac/0xcf0 net/bridge/br_ioctl.c:418 1 lock held by syz.2.4491/17943: #0: ffffffff8cb826a8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239 1 lock held by syz.2.4491/17951: #0: ffffffff8dd469e8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x54d/0xe80 net/core/dev_ioctl.c:571 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4553 Comm: kworker/u4:8 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_preemption_disabled+0x60/0x110 lib/smp_processor_id.c:19 Code: 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 <74> cc 65 4c 8b 3d a6 54 d5 75 41 f6 47 2f 04 74 0a 41 83 bf 10 04 RSP: 0018:ffffc90004c4fa88 EFLAGS: 00000046 RAX: 0000000000000001 RBX: b98d254c0818c18a RCX: 0000000080000000 RDX: 0000000000000002 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0f60 RBP: ffffc90004c4fbd0 R08: ffffffff8e1fd76f R09: 1ffffffff1c3faed R10: dffffc0000000000 R11: fffffbfff1c3faee R12: ffff88802c0de470 R13: dffffc0000000000 R14: ffff88802c0de410 R15: 1ffff92000989f64 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000d12000 CR3: 000000000c88e000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_release+0x558/0x920 kernel/locking/lockdep.c:5684 rcu_lock_release include/linux/rcupdate.h:355 [inline] rcu_read_unlock include/linux/rcupdate.h:824 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x28d/0x600 net/batman-adv/network-coding.c:719 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295