INFO: task syz.3.3868:18359 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.3868 state:D stack:22416 pid:18359 ppid:16060 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 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x982/0x2480 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 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: 0033:0x7f244259c819 RSP: 002b:00007f24434d1fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffff4 RBX: 00007f2442815fa0 RCX: 00007f244259c819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ae12e400 RBP: 00007f2442632c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f2442816038 R14: 00007f2442815fa0 R15: 00007ffcf9978f88 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2df70 (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: ffffffff8cb2e790 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 3 locks held by kworker/0:1/14: 1 lock held by khungtaskd/27: #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by getty/4026: #0: ffff88802fb76098 (&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 2 locks held by kworker/1:3/4313: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90004aa7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 2 locks held by kworker/1:5/4318: #0: ffff8880b8f3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538 #1: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: do_perf_sw_event kernel/events/core.c:9736 [inline] #1: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: ___perf_sw_event+0x180/0x6e0 kernel/events/core.c:9774 1 lock held by syz.5.4625/21310: #0: ffff888072b98158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable+0x1d/0x60 include/linux/mmap_lock.h:126 6 locks held by syz.5.4625/21311: 2 locks held by syz.4.4626/21312: #0: ffffffff8dd47f68 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd47f68 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3492 #1: ffffffff8cb332b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #1: ffffffff8cb332b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 21311 Comm: syz.5.4625 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:rcu_lockdep_current_cpu_online+0xed/0x120 kernel/rcu/tree.c:778 Code: 67 00 4c 85 3b 75 1a 48 c7 c7 40 34 b3 8c be 04 00 00 00 e8 15 11 67 00 83 3d 2e c2 46 0b 00 74 11 b0 01 65 ff 0d 2b fd 95 7e <74> 0a 5b 41 5e 41 5f c3 31 c0 eb ed e8 8a 11 94 ff eb ef 48 c7 c7 RSP: 0018:ffffc90000007810 EFLAGS: 00000082 RAX: 1ffffffff1966501 RBX: ffffffff8cb32bb0 RCX: 3a8a5fdf17de1c00 RDX: ffff888029ab0000 RSI: ffffffff8adf1380 RDI: ffff8880b8e3b9e0 RBP: ffffc90000007970 R08: ffffc900000078f7 R09: ffffc900000078e0 R10: dffffc0000000000 R11: fffff52000000f1f R12: 1ffff92000000f18 R13: ffffc900000079c0 R14: dffffc0000000000 R15: 0000000000000001 FS: 00007f1d12f0a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c368a28 CR3: 00000000732a8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held+0x1a/0x40 kernel/rcu/update.c:309 __perf_output_begin kernel/events/ring_buffer.c:170 [inline] perf_output_begin_forward+0x1d1/0xa80 kernel/events/ring_buffer.c:272 __perf_event_output kernel/events/core.c:7732 [inline] perf_event_output_forward+0x1ad/0x2f0 kernel/events/core.c:7750 __perf_event_overflow+0x448/0x610 kernel/events/core.c:9496 perf_event_overflow kernel/events/core.c:9517 [inline] perf_swevent_hrtimer+0x472/0x630 kernel/events/core.c:10967 __run_hrtimer kernel/time/hrtimer.c:1747 [inline] __hrtimer_run_queues+0x50b/0xd50 kernel/time/hrtimer.c:1811 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:_compound_head include/linux/page-flags.h:255 [inline] RIP: 0010:PageAnon include/linux/page-flags.h:669 [inline] RIP: 0010:copy_present_pte mm/memory.c:958 [inline] RIP: 0010:copy_pte_range mm/memory.c:1091 [inline] RIP: 0010:copy_pmd_range mm/memory.c:1177 [inline] RIP: 0010:copy_pud_range mm/memory.c:1214 [inline] RIP: 0010:copy_p4d_range mm/memory.c:1238 [inline] RIP: 0010:copy_page_range+0x129f/0x3900 mm/memory.c:1332 Code: 85 c0 48 89 44 24 30 0f 84 d4 01 00 00 4c 8d 78 08 4c 89 fb 48 c1 eb 03 42 80 3c 2b 00 74 08 4c 89 ff e8 a4 62 14 00 4d 8b 37 <4c> 89 f6 48 83 e6 01 31 ff e8 33 5a c3 ff 4c 89 f0 48 83 e0 01 0f RSP: 0018:ffffc90004c8f540 EFLAGS: 00000246 RAX: ffffea00017d8900 RBX: 1ffffd40002fb121 RCX: 0000000000080000 RDX: ffffc90011a45000 RSI: 00000000000402bb RDI: 00000000000402bc RBP: ffffc90004c8f850 R08: ffff888027aa16c3 R09: 1ffff11004f542d8 R10: dffffc0000000000 R11: ffffed1004f542d9 R12: ffff888057a28dc0 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffea00017d8908 dup_mmap kernel/fork.c:702 [inline] dup_mm kernel/fork.c:1546 [inline] copy_mm+0xec3/0x1690 kernel/fork.c:1595 copy_process+0x1979/0x4030 kernel/fork.c:2356 kernel_clone+0x24b/0x900 kernel/fork.c:2762 __do_sys_clone kernel/fork.c:2903 [inline] __se_sys_clone kernel/fork.c:2887 [inline] __x64_sys_clone+0x1a7/0x220 kernel/fork.c:2887 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1d11f9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1d12f09fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f1d12215fa0 RCX: 00007f1d11f9c819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000108000 RBP: 00007f1d12032c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f1d12216038 R14: 00007f1d12215fa0 R15: 00007ffc97b74a88