INFO: task syz.3.1156:9285 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1156 state:D stack:26376 pid:9285 tgid:9283 ppid:5828 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5262 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6870 __schedule_loop kernel/sched/core.c:6952 [inline] schedule+0x165/0x360 kernel/sched/core.c:6967 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7024 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 bdev_open+0xe0/0xd30 block/bdev.c:962 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1076 setup_bdev_super+0x5a/0x5b0 fs/super.c:1615 get_tree_bdev_flags+0x366/0x4d0 fs/super.c:1695 vfs_get_tree+0x92/0x2b0 fs/super.c:1757 fc_mount fs/namespace.c:1209 [inline] do_new_mount_fc fs/namespace.c:3652 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3728 do_mount fs/namespace.c:4051 [inline] __do_sys_mount fs/namespace.c:4240 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4217 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd7fa78f6c9 RSP: 002b:00007fd7fb5cd038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fd7fa9e5fa0 RCX: 00007fd7fa78f6c9 RDX: 0000200000000080 RSI: 0000200000000040 RDI: 0000200000000000 RBP: 00007fd7fa811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000020080c4 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd7fa9e6038 R14: 00007fd7fa9e5fa0 R15: 00007ffdc783d728 Showing all locks held in the system: 3 locks held by kworker/1:0/24: #0: ffff8880b873a1d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638 #1: ffff8880b8724048 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 #2: ffff8880b8725b98 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1004 [inline] #2: ffff8880b8725b98 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30 kernel/time/timer.c:1085 1 lock held by khungtaskd/31: #0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 5 locks held by kworker/u8:3/37: #0: ffff88801badf148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x841/0x15e0 kernel/workqueue.c:3236 #1: ffffc90000ad7b80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x868/0x15e0 kernel/workqueue.c:3237 #2: ffffffff8f6e7c50 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7a0 net/core/net_namespace.c:670 #3: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890 net/core/dev.c:13033 #4: ffffffff8e343038 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #4: ffffffff8e343038 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957 3 locks held by kworker/u8:6/1339: #0: ffff88813fe69948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work+0x841/0x15e0 kernel/workqueue.c:3236 #1: ffffc90003fffb80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x868/0x15e0 kernel/workqueue.c:3237 #2: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by dhcpcd/5490: #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5027 2 locks held by getty/5585: #0: ffff88814de8e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by udevd/5821: #0: ffff888025b85358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 5 locks held by kworker/0:3/5823: #0: ffff88801e6a3548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15e0 kernel/workqueue.c:3236 #1: ffffc90003fdfb80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15e0 kernel/workqueue.c:3237 #2: ffff888143b5c198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff888143b5c198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0 drivers/usb/core/hub.c:5899 #3: ffff888143b5f518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff888143b5f518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff888143b5f518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff888143b5f518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff888143b5f518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x215a/0x4ef0 drivers/usb/core/hub.c:5953 #4: ffff8880287f5468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff8880287f5468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff8880287f5468 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff8880287f5468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2182/0x4ef0 drivers/usb/core/hub.c:5953 1 lock held by udevd/5834: #0: ffff888141b07358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/5835: #0: ffff8881413b1358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/5934: #0: ffff888141b19358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/5944: #0: ffff888141b01358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6331: #0: ffff888025b83358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6381: #0: ffff8881417d7358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6472: #0: ffff8881417d3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6590: #0: ffff8881417a8358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6591: #0: ffff888141b03358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/6616: #0: ffff888025e2b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 2 locks held by syz.3.1156/9285: #0: ffff8880223640e0 (&type->s_umount_key#66/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xaa0 fs/super.c:344 #1: ffff888025b85358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by syz.5.1497/10431: #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 2 locks held by syz-executor/12242: #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 2 locks held by syz-executor/12246: #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8ee84b48 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 1 lock held by syz.1.2102/12290: #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f6f51c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:336 [inline] watchdog+0xfa8/0xff0 kernel/hung_task.c:499 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 83 f1 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 6a 24 00 f3 0f 1e fa fb f4 58 f1 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6 RAX: f9387ea281179300 RBX: ffffffff81976ec7 RCX: f9387ea281179300 RDX: 0000000000000001 RSI: ffffffff8da8bedc RDI: ffffffff8be131e0 RBP: ffffffff8e007ea8 R08: ffff8880b863319b R09: 1ffff110170c6633 R10: dffffc0000000000 R11: ffffed10170c6634 R12: ffffffff8fbf8c70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a60 FS: 0000000000000000(0000) GS:ffff888125a76000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1b2f5729e0 CR3: 000000000e138000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3a7/0x410 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147