INFO: task syz.2.3288:13445 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.3288 state:D stack:25616 pid:13445 ppid: 12492 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 perf_pending_task_sync+0x13c/0x1c0 kernel/events/core.c:5137 _free_event+0x34/0xe30 kernel/events/core.c:5143 put_event kernel/events/core.c:5268 [inline] perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5393 perf_release+0x37/0x40 kernel/events/core.c:5403 __fput+0x212/0x8c0 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x635/0x2110 kernel/exit.c:890 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fca4a9b3159 RSP: 002b:00007fca48c0af38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fca4aa20558 RCX: 00007fca4a9b3159 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000e R08: 0000000000000000 R09: 00007fca4ac3b038 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fca4ac3b038 R14: 00007fca4ac3afa0 R15: 00007ffcb66cc888 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by getty/3944: #0: ffff88814cde3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158 4 locks held by kworker/u4:7/4648: 2 locks held by kworker/1:8/11201: #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000306fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 2 locks held by syz.3.4318/17071: 3 locks held by syz.4.4321/17085: 2 locks held by syz.4.4334/17130: 1 lock held by syz.4.4337/17138: #0: ffffffff8d44cd08 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722 2 locks held by syz.1.4339/17143: #0: ffffffff8d44cd08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline] #0: ffffffff8d44cd08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3443 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845 1 lock held by syz.0.4343/17168: #0: ffffffff8d44cd08 (rtnl_mutex){+.+.}-{3:3}, at: ppp_release+0x86/0x1f0 drivers/net/ppp/ppp_generic.c:418 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17071 Comm: syz.3.4318 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:211 Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 RSP: 0018:ffffc9000340f778 EFLAGS: 00000246 RAX: ffffffff88678c73 RBX: 0000000000000001 RCX: ffff888020bf3b80 RDX: ffffc90014ec1000 RSI: 000000000007ffff RDI: ffffffff8a7a4360 RBP: ffffc9000340f870 R08: dffffc0000000000 R09: 1ffffffff203de18 R10: dffffc0000000000 R11: fffffbfff203de19 R12: dffffc0000000000 R13: dffffc0000000000 R14: 000000000003d4f9 R15: ffffffff8d6286c8 FS: 00007fefc70006c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c230000 CR3: 0000000040c93000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_read_unlock include/linux/rcupdate.h:769 [inline] inet_twsk_purge+0x713/0x820 net/ipv4/inet_timewait_sock.c:309 ops_exit_list net/core/net_namespace.c:177 [inline] setup_net+0x842/0xa10 net/core/net_namespace.c:365 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110 copy_namespaces+0x378/0x3d0 kernel/nsproxy.c:178 copy_process+0x17f0/0x3e70 kernel/fork.c:2295 kernel_clone+0x23f/0x990 kernel/fork.c:2682 __do_sys_clone kernel/fork.c:2799 [inline] __se_sys_clone kernel/fork.c:2783 [inline] __x64_sys_clone+0x19a/0x210 kernel/fork.c:2783 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fefc8da8159 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:00007fefc6ffffd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fefc902ffa0 RCX: 00007fefc8da8159 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000004004261f RBP: 00007fefc8e3f024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fefc9030038 R14: 00007fefc902ffa0 R15: 00007ffe8d4064c8