INFO: task syz-executor:4937 blocked for more than 143 seconds. Not tainted 6.1.142-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22144 pid:4937 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 wb_wait_for_completion+0x162/0x280 fs/fs-writeback.c:191 sync_inodes_sb+0x1b8/0x9e0 fs/fs-writeback.c:2739 sync_filesystem+0x16d/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1182 task_work_run+0x1ca/0x250 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x93e/0x2400 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 __do_sys_exit_group kernel/exit.c:1033 [inline] __se_sys_exit_group kernel/exit.c:1031 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f04ea38e929 RSP: 002b:00007ffec8b63608 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f04ea4109a9 RCX: 00007f04ea38e929 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000027 R08: 00007ffec8b613a6 R09: 00007ffec8b648c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffec8b648c0 R13: 00007f04ea410925 R14: 000055558c4804a8 R15: 00007ffec8b66a80 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c92b430 (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: ffffffff8c92bc50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by kworker/u4:4/75: #0: ffff888144a4d938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc900015e7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 3 locks held by kworker/1:2/128: #0: ffff88802fcc8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90002d77d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db34ee8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4137 2 locks held by getty/4019: #0: ffff8880303ee098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000326b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 2 locks held by kworker/1:3/4242: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003c47d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 3 locks held by kworker/0:4/4296: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90004647d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffff8880554fb240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26b/0x32b0 drivers/net/netdevsim/fib.c:1491 2 locks held by syz-executor/4937: #0: ffff8880281840e0 (&type->s_umount_key#66){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 #1: ffff888143b207d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff888143b207d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2737 1 lock held by segctord/5362: 3 locks held by kworker/1:9/5364: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003b97d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #2: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962 2 locks held by kworker/1:11/5366: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003bb7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 4 locks held by syz-executor/5558: #0: ffff88802f0290b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline] #0: ffff88802f0290b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705 #1: ffff88802f028078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5175 #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1799 [inline] #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2503 #3: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #3: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962 1 lock held by syz-executor/5560: #0: ffffffff8db34ee8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8db34ee8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3492 3 locks held by syz-executor/5656: #0: ffff88807997d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline] #0: ffff88807997d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705 #1: ffff88807997c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5175 #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1799 [inline] #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2503 3 locks held by syz-executor/6453: #0: ffff88807b38d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline] #0: ffff88807b38d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1fa/0x4f0 net/bluetooth/hci_core.c:2705 #1: ffff88807b38c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x458/0xf40 net/bluetooth/hci_sync.c:5175 #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1799 [inline] #2: ffffffff8dc923e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2503 1 lock held by syz-executor/6876: #0: ffffffff8db34ee8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_wait_allrefs_any net/core/dev.c:10370 [inline] #0: ffffffff8db34ee8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x668/0xd80 net/core/dev.c:10489 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.1.142-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 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: 3606 Comm: syslogd Not tainted 6.1.142-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:444 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1030 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xd4/0x490 kernel/locking/lockdep.c:5633 Code: 38 84 c0 0f 85 87 02 00 00 44 3b 35 a6 a4 9b 0c 0f 83 8c 01 00 00 45 89 f4 41 c1 ee 06 4a 8d 3c f5 28 8d fe 8d be 08 00 00 00 17 6a 6f 00 4c 0f a3 25 77 a2 9b 0c 73 0d e8 d8 1b 08 00 84 c0 RSP: 0018:ffffc90003267780 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8dfe8d28 RBP: ffffc90003267888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff9200064cefc R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f4eccfd5c80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563420a99000 CR3: 000000007e776000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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+0x109/0xa40 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_iter include/linux/uio.h:178 [inline] simple_copy_to_iter+0x3e/0x60 net/core/datagram.c:521 __skb_datagram_iter+0xde/0x740 net/core/datagram.c:419 skb_copy_datagram_iter+0xd7/0x290 net/core/datagram.c:535 skb_copy_datagram_msg include/linux/skbuff.h:3956 [inline] __unix_dgram_recvmsg+0x658/0xd70 net/unix/af_unix.c:2486 sock_recvmsg_nosec net/socket.c:1022 [inline] sock_recvmsg net/socket.c:1040 [inline] sock_read_iter+0x2bf/0x370 net/socket.c:1121 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x434/0x920 fs/read_write.c:470 ksys_read+0x143/0x240 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4ecd125407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fffa6f92990 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f4eccfd5c80 RCX: 00007f4ecd125407 RDX: 00000000000000ff RSI: 0000558504018950 RDI: 0000000000000000 RBP: 0000558504018910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00005585040189a3 R13: 0000000000000000 R14: 0000558504018950 R15: 00005584f21edd98