INFO: task kworker/u8:7:2907 blocked for more than 143 seconds. Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:7 state:D stack:20736 pid:2907 tgid:2907 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5366 [inline] __schedule+0x1ac3/0x5090 kernel/sched/core.c:6747 __schedule_loop kernel/sched/core.c:6824 [inline] schedule+0x163/0x360 kernel/sched/core.c:6839 afs_cell_purge+0x3e3/0x550 fs/afs/cell.c:893 afs_net_exit+0x50/0x100 fs/afs/main.c:146 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x814/0xd60 net/core/net_namespace.c:654 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd30 kernel/workqueue.c:3400 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8eb3a260 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8eb3a260 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8eb3a260 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6761 3 locks held by kworker/u8:7/2907: #0: ffff88801baf3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801baf3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9000c5d7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000c5d7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff8feb8fd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x17c/0xd60 net/core/net_namespace.c:608 2 locks held by getty/5577: #0: ffff88803525a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000331b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x53d/0x16b0 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5834: #0: ffffffff8fec5c08 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff8fec5c08 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3390 3 locks held by kworker/1:1/15450: #0: ffff88801ac80d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801ac80d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319 #1: ffffc9000cc0fc60 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000cc0fc60 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319 #2: ffffffff8eb3f778 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #2: ffffffff8eb3f778 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x384/0x830 kernel/rcu/tree_exp.h:998 1 lock held by syz-executor/16072: 3 locks held by syz-executor/16079: #0: ffff88804d180d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline] #0: ffff88804d180d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x203/0x510 net/bluetooth/hci_core.c:2678 #1: ffff88804d180078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x60f/0x1260 net/bluetooth/hci_sync.c:5213 #2: ffffffff8eb3f778 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #2: ffffffff8eb3f778 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x454/0x830 kernel/rcu/tree_exp.h:998 1 lock held by syz-executor/16085: 4 locks held by syz-executor/16093: #0: ffff888041b58d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:481 [inline] #0: ffff888041b58d80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x203/0x510 net/bluetooth/hci_core.c:2678 #1: ffff888041b58078 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x60f/0x1260 net/bluetooth/hci_sync.c:5213 #2: ffffffff9002bc08 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2066 [inline] #2: ffffffff9002bc08 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa6/0x240 net/bluetooth/hci_conn.c:2701 #3: ffff88804af33338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x71/0x690 net/bluetooth/l2cap_core.c:1761 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0x1058/0x10a0 kernel/hung_task.c:399 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17330 Comm: syz.5.3094 Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__page_table_check_zero+0x161/0x350 mm/page_table_check.c:157 Code: 00 00 e8 a2 22 f4 ff 48 89 e8 48 c1 e8 03 0f b6 04 18 84 c0 75 6a 8b 5d 00 31 ff 89 de e8 e7 7c 8e ff 85 db 0f 85 05 01 00 00 <48> 83 c5 04 48 89 ef be 04 00 00 00 e8 6e 22 f4 ff 48 89 e8 48 c1 RSP: 0018:ffffc90004bd7828 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8234ed9e RDX: ffff888036988000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88801d9a3a08 R08: ffffffff8234edb9 R09: 1ffff11003b34741 R10: dffffc0000000000 R11: ffffed1003b34742 R12: ffff88801d9a39c0 R13: 1ffffffff349fedc R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125243000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9ae8ed7d60 CR3: 000000000e938000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1128 [inline] free_frozen_pages+0xe21/0x10e0 mm/page_alloc.c:2660 vfree+0x1c3/0x360 mm/vmalloc.c:3383 kcov_put kernel/kcov.c:439 [inline] kcov_close+0x28/0x50 kernel/kcov.c:535 __fput+0x3e9/0x9f0 fs/file_table.c:465 task_work_run+0x251/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2a/0x2940 kernel/exit.c:954 do_group_exit+0x207/0x2c0 kernel/exit.c:1103 get_signal+0x1696/0x1730 kernel/signal.c:3035 arch_do_signal_or_restart+0x98/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbb5598d169 Code: Unable to access opcode bytes at 0x7fbb5598d13f. RSP: 002b:00007fbb567f5038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007fbb55ba6080 RCX: 00007fbb5598d169 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007fbb55a0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fbb55ba6080 R15: 00007ffff1678a88