INFO: task syz.6.1399:10471 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.1399 state:D stack:24816 pid:10471 ppid:4479 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x107f/0x4030 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+0x176/0x1050 kernel/events/core.c:5037 put_event kernel/events/core.c:5162 [inline] perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5287 perf_release+0x37/0x40 kernel/events/core.c:5297 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9d5/0x2570 kernel/exit.c:881 do_group_exit+0x229/0x2e0 kernel/exit.c:1024 get_signal+0x1259/0x1340 kernel/signal.c:2872 arch_do_signal_or_restart+0xc4/0x1310 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: 0033:0x7fc013f9de59 RSP: 002b:00007fc0121f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffff91 RBX: 00007fc014225fa0 RCX: 00007fc013f9de59 RDX: 0000000000004000 RSI: 0000200000000700 RDI: 0000000000000007 RBP: 00007fc014033e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc014226038 R14: 00007fc014225fa0 R15: 00007ffce6199688 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 2 locks held by kworker/1:0/22: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc900001c7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 1 lock held by khungtaskd/28: #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527 2 locks held by getty/4026: #0: ffff8880302c5098 (&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+0x41e/0x1360 drivers/tty/n_tty.c:2198 3 locks held by kworker/1:3/4315: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90004057d00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/u4:7/4333: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90004137d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 2 locks held by syz.2.2190/13453: 1 lock held by syz.8.2197/13468: #0: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 1 lock held by syz.9.2195/13470: #0: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 1 lock held by syz.9.2195/13471: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x54d/0xe80 net/core/dev_ioctl.c:571 2 locks held by syz.9.2195/13476: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 1 lock held by syz.9.2195/13480: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: wext_ioctl_dispatch+0xaf/0x470 net/wireless/wext-core.c:996 1 lock held by syz.9.2195/13484: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6155 1 lock held by syz.7.2199/13472: #0: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 1 lock held by syz.7.2199/13479: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6155 1 lock held by syz.2.2198/13474: #0: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 1 lock held by syz.2.2198/13481: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6155 1 lock held by syz.5.2200/13485: #0: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 1 lock held by syz.5.2200/13486: #0: ffffffff8dd58c28 (rtnl_mutex){+.+.}-{3:3}, at: __netlink_dump_start+0x11e/0x6f0 net/netlink/af_netlink.c:2310 2 locks held by syz.5.2200/13488: #0: ffff88807938d0b0 (&ctx->mutex){+.+.}-{3:3}, at: perf_event_ctx_lock_nested+0x3b5/0x490 kernel/events/core.c:1309 #1: ffffffff8cb8c828 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_attach_bpf_prog+0xc7/0x390 kernel/trace/bpf_trace.c:2145 ============================================= 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 06/25/2026 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+0xf0e/0xf50 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: 4300 Comm: kworker/u4:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_release kernel/locking/lockdep.c:5380 [inline] RIP: 0010:lock_release+0x2ce/0x920 kernel/locking/lockdep.c:5696 Code: 85 d3 04 00 00 45 89 2e 45 85 ff 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 18 0f 85 88 02 00 00 48 8b 44 24 40 42 0f b6 04 28 <84> c0 0f 85 80 04 00 00 48 8b 04 24 89 10 4c 89 e0 48 c1 e8 03 42 RSP: 0018:ffffc90003f77560 EFLAGS: 00000083 RAX: 0000000000000000 RBX: 1ffff11004ba68ea RCX: 0000000000000001 RDX: 0000000000000002 RSI: ffff8880b8f3ad18 RDI: ffff888025d34730 RBP: ffffc90003f77680 R08: ffffffff8e2121af R09: 1ffffffff1c42435 R10: dffffc0000000000 R11: fffffbfff1c42436 R12: ffff888025d34730 R13: dffffc0000000000 R14: ffff888025d34750 R15: 1ffff920007eeeb8 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33e0bff8 CR3: 000000000c88e000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186 raw_spin_rq_unlock kernel/sched/core.c:582 [inline] raw_spin_rq_unlock_irq kernel/sched/sched.h:1373 [inline] finish_lock_switch kernel/sched/core.c:5004 [inline] finish_task_switch+0x25d/0x8e0 kernel/sched/core.c:5122 context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1087/0x4030 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:87 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] RIP: 0010:kasan_check_range+0x8a/0x290 mm/kasan/generic.c:189 Code: 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 0f 85 86 01 00 00 <49> ff c3 48 ff c3 75 ee e9 18 01 00 00 44 89 dd 83 e5 07 0f 84 b5 RSP: 0018:ffffc90003f77a10 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff8163f3f4 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e2121a8 RBP: ffffc90003f77b60 R08: ffffffff8e2121af R09: 1ffffffff1c42435 R10: dffffc0000000000 R11: fffffbfff1c42435 R12: dffffc0000000001 R13: 1ffff920007eef54 R14: 1ffffffff1c42435 R15: 0000000000000001 instrument_atomic_read include/linux/instrumented.h:72 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:444 [inline] cpu_online include/linux/cpumask.h:1030 [inline] trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xd4/0x4a0 kernel/locking/lockdep.c:5647 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] batadv_nc_process_nc_paths+0xdb/0x380 net/batman-adv/network-coding.c:687 batadv_nc_worker+0x41f/0x600 net/batman-adv/network-coding.c:728 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295