INFO: task syz.3.266:5474 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.266 state:D stack:22544 pid:5474 ppid:4278 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 perf_pending_task_sync kernel/events/core.c:5041 [inline] _free_event+0x176/0x1050 kernel/events/core.c:5047 put_event kernel/events/core.c:5172 [inline] perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5297 perf_release+0x37/0x40 kernel/events/core.c:5307 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x118d/0x1340 kernel/signal.c:2657 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: 0033:0x7f31af59e159 RSP: 002b:00007f31ad7f5fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffffc RBX: 00007f31af826090 RCX: 00007f31af59e159 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000041b08000 RBP: 00007f31af63503b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f31af826128 R14: 00007f31af826090 R15: 00007ffe315e1ca8 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2e5b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 2 locks held by rcu_tasks_trace/13: #0: ffffffff8cb2edd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 #1: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 1 lock held by khungtaskd/28: #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527 2 locks held by kworker/0:2/127: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90002e27d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 2 locks held by getty/4029: #0: ffff88807e2c8098 (&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 1 lock held by syz-executor/4274: #0: ffff8880b8e3acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538 2 locks held by kworker/0:4/4286: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90004297d00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 3 locks held by kworker/u4:10/7099: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc900056e7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 1 lock held by syz.2.945/8085: 1 lock held by syz.2.945/8088: #0: ffffffff8cb8ca88 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 2 locks held by syz.4.962/8128: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495 #1: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #1: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 1 lock held by syz.2.963/8134: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: ppp_release+0x86/0x1f0 drivers/net/ppp/ppp_generic.c:406 1 lock held by syz.0.968/8162: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107 1 lock held by syz.0.968/8175: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107 1 lock held by syz.0.968/8176: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107 2 locks held by syz.1.969/8167: 1 lock held by syz.5.970/8169: #0: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x2c8/0xe80 net/core/dev_ioctl.c:527 1 lock held by syz.1.972/8181: #0: ffffffff8cb8ca88 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x87/0x310 kernel/trace/bpf_trace.c:2178 2 locks held by syz.1.972/8182: #0: ffffffff8dd427c8 (vlan_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x21b/0x700 net/socket.c:1283 #1: ffffffff8dd5c928 (rtnl_mutex){+.+.}-{3:3}, at: vlan_ioctl_handler+0xef/0x5c0 net/8021q/vlan.c:580 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 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+0x188/0x24e 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3628 Comm: klogd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x8e/0x4a0 kernel/locking/lockdep.c:5647 Code: 20 09 64 81 4c 8d 6c 24 60 49 c1 ed 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4b 89 44 3d 00 43 c7 44 3d 08 f8 f3 f3 f3 cc 01 03 00 00 <65> 44 8b 35 ea 0f 9e 7e 48 c7 c0 b0 18 21 8e 48 c1 e8 03 42 0f b6 RSP: 0018:ffffc900032d7a20 EFLAGS: 00000a06 RAX: f2f2f2f8f1f1f1f1 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cb2dce0 RBP: ffffc900032d7b30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: dffffc0000000000 R13: 1ffff9200065af50 R14: ffffffff8139fec8 R15: dffffc0000000000 FS: 00007fe69bac6c80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558a5b74e8 CR3: 0000000030b8a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock_sched include/linux/rcupdate.h:883 [inline] pfn_valid include/linux/mmzone.h:1857 [inline] __virt_addr_valid+0x1a5/0x540 arch/x86/mm/physaddr.c:65 check_heap_object mm/usercopy.c:188 [inline] __check_object_size+0x106/0xa70 mm/usercopy.c:250 check_object_size include/linux/thread_info.h:199 [inline] check_copy_size include/linux/thread_info.h:235 [inline] copy_to_user include/linux/uaccess.h:168 [inline] syslog_print+0x4a9/0x630 kernel/printk/printk.c:1577 do_syslog+0x817/0x900 kernel/printk/printk.c:1679 __do_sys_syslog kernel/printk/printk.c:1771 [inline] __se_sys_syslog kernel/printk/printk.c:1769 [inline] __x64_sys_syslog+0x78/0x90 kernel/printk/printk.c:1769 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: 0033:0x7fe69bc90a37 Code: 73 01 c3 48 8b 0d c1 f3 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 f3 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffef2952798 EFLAGS: 00000206 ORIG_RAX: 0000000000000067 RAX: ffffffffffffffda RBX: 00007fe69be30490 RCX: 00007fe69bc90a37 RDX: 00000000000003ff RSI: 00007fe69be30490 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000206 R12: 00007fe69be30490 R13: 00007fe69be0ddfe R14: 00007fe69be304f3 R15: 00007fe69be304f3