INFO: task syz.7.2439:15563 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.2439 state:D stack:24584 pid:15563 tgid:15560 ppid:13178 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 device_lock include/linux/device.h:914 [inline] usbdev_release+0x7e/0x760 drivers/usb/core/devio.c:1099 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:966 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f241eb8efc9 RSP: 002b:00007f241cdf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffffc RBX: 00007f241ede5fa0 RCX: 00007f241eb8efc9 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000007 RBP: 00007f241ec11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f241ede6038 R14: 00007f241ede5fa0 R15: 00007f241ef0fa28 Showing all locks held in the system: 4 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:4/60: #0: ffff88814db0d948 ((wq_completion)udp_tunnel_nic){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88814db0d948 ((wq_completion)udp_tunnel_nic){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000211fba0 ((work_completion)(&utn->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000211fba0 ((work_completion)(&utn->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: udp_tunnel_nic_device_sync_work+0x29/0xa50 net/ipv4/udp_tunnel_nic.c:736 3 locks held by kworker/u8:6/1151: #0: ffff88802eedf948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88802eedf948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90003eafba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90003eafba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 3 locks held by kworker/u8:7/1345: #0: ffff88801a069948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a069948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900043afba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900043afba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by dhcpcd/5497: #0: ffff8880576076e8 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2406 #1: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6819 2 locks held by getty/5584: #0: ffff88814da510a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by udevd/5828: 4 locks held by udevd/5843: #0: ffff88805a17a2f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:182 #1: ffff8880788e1088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 #2: ffff888068faa5a8 (kn->active#31){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888068faa5a8 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173 #3: ffff88807e851198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline] #3: ffff88807e851198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:4/5904: #0: ffff8880216a3d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff8880216a3d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900050d7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900050d7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898 #3: ffff88807e851198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #3: ffff88807e851198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006 #4: ffff888023b74160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff888023b74160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006 #5: ffffffff8dde2830 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xf0/0x2b0 kernel/umh.c:214 3 locks held by kworker/0:6/5913: #0: ffff88801a055948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a055948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90005167ba0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90005167ba0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 1 lock held by syz.7.2439/15563: #0: ffff888144ff2198 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] &dev->mutex){....}-{4:4}, at: usbdev_release+0x7e/0x760 drivers/usb/core/devio.c:1099 1 lock held by syz.6.2631/16279: #0: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #0: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054 1 lock held by syz.4.2938/17660: #0: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #0: ffff888144ff2198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054 1 lock held by syz-executor/18144: #0: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz.8.3050/18261: #0: ffffffff8f2cb648 (rtnl_mutex){+.+.}-{4:4}, at: ppp_release+0x87/0x1f0 drivers/net/ppp/ppp_generic.c:413 ============================================= 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 10/02/2025 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:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 f3 f1 21 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: de07a9c699623a00 RBX: ffffffff81967bf7 RCX: de07a9c699623a00 RDX: 0000000000000001 RSI: ffffffff8d70d450 RDI: ffffffff8bbf0760 RBP: ffffffff8dc07ea8 R08: ffff8880b8832fdb R09: 1ffff110171065fb R10: dffffc0000000000 R11: ffffed10171065fc R12: ffffffff8f7cdc70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a40 FS: 0000000000000000(0000) GS:ffff88812613d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2ead1c CR3: 0000000076dee000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 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+0x3ae/0x410 init/main.c:1111 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