INFO: task udevd:4176 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24752 pid: 4176 ppid: 3560 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503 wait_on_page_bit_common+0x83b/0xe50 mm/filemap.c:1356 wait_on_page_bit mm/filemap.c:1417 [inline] wait_on_page_locked include/linux/pagemap.h:688 [inline] wait_on_page_read mm/filemap.c:3437 [inline] do_read_cache_page+0xb05/0x1030 mm/filemap.c:3480 read_mapping_page include/linux/pagemap.h:515 [inline] read_part_sector+0xd4/0x4f0 block/partitions/core.c:726 adfspart_check_ICS+0xc3/0xe40 block/partitions/acorn.c:360 check_partition block/partitions/core.c:148 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x933/0x16c0 block/partitions/core.c:697 blkdev_get_whole+0x2f9/0x390 block/bdev.c:682 blkdev_get_by_dev+0x2d0/0xa60 block/bdev.c:827 blkdev_open+0x12d/0x2c0 block/fops.c:466 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3616 [inline] path_openat+0x26f5/0x2fa0 fs/namei.c:3750 do_filp_open+0x1e2/0x410 fs/namei.c:3777 do_sys_openat2+0x150/0x4b0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f470d9c3407 RSP: 002b:00007fffb01d01a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f470d8d5880 RCX: 00007f470d9c3407 RDX: 00000000000a0800 RSI: 000055d7671fc780 RDI: ffffffffffffff9c RBP: 000055d7671e4910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055d7671f8ba0 R13: 000055d7671fc410 R14: 0000000000000000 R15: 000055d7671f8ba0 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by getty/3948: #0: ffff88802bfc7098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900021ce2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158 1 lock held by udevd/4176: #0: ffff888020754518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820 4 locks held by udevd/4177: #0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:483 #1: ffff8880b9135df8 (lock){-.-.}-{2:2}, at: local_lock_acquire+0x5/0x120 include/linux/local_lock_internal.h:28 #2: ffff88807d30fd58 (&ep->lock){....}-{2:2}, at: ep_poll_callback+0x7b/0x9f0 fs/eventpoll.c:1176 #3: ffff88807d30fca8 (&ep->wq){....}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline] #3: ffff88807d30fca8 (&ep->wq){....}-{2:2}, at: __wake_up_sync_key kernel/sched/wait.c:205 [inline] #3: ffff88807d30fca8 (&ep->wq){....}-{2:2}, at: __wake_up_sync+0xf8/0x190 kernel/sched/wait.c:237 4 locks held by udevd/4178: #0: ffff888052af1540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182 #1: ffff88805f825888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3c0 fs/kernfs/file.c:112 #2: ffff88801ed84830 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x71/0x3c0 fs/kernfs/file.c:113 #3: ffff88807a88e1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #3: ffff88807a88e1a8 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17a/0x330 drivers/base/core.c:2408 3 locks held by kworker/u5:6/4199: #0: ffff88802114e938 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc900022f7d00 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff88805ae18ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xa4/0x1270 net/bluetooth/hci_core.c:1446 5 locks held by kworker/1:11/8536: #0: ffff8881423e9138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90003dbfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff888023f69220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #2: ffff888023f69220 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x55e0 drivers/usb/core/hub.c:5827 #3: ffff888023f6c5c0 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3168 [inline] #3: ffff888023f6c5c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5393 [inline] #3: ffff888023f6c5c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5637 [inline] #3: ffff888023f6c5c0 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5799 [inline] #3: ffff888023f6c5c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x2260/0x55e0 drivers/usb/core/hub.c:5881 #4: ffff888148204e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5394 [inline] #4: ffff888148204e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5637 [inline] #4: ffff888148204e68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5799 [inline] #4: ffff888148204e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x2299/0x55e0 drivers/usb/core/hub.c:5881 5 locks held by kworker/0:15/8941: #0: ffff8881423e9138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90003e5fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff888148259220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #2: ffff888148259220 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x55e0 drivers/usb/core/hub.c:5827 #3: ffff88807823f220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #3: ffff88807823f220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954 #4: ffff88807a88e1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #4: ffff88807a88e1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954 2 locks held by syz.3.1254/9099: #0: ffff88807a88c098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:300 [inline] #0: ffff88807a88c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:356 [inline] #0: ffff88807a88c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:377 [inline] #0: ffff88807a88c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_release+0xb3/0x200 drivers/tty/tty_ldisc.c:802 #1: ffff88807a88d098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: __tty_ldisc_lock_nested drivers/tty/tty_ldisc.c:306 [inline] #1: ffff88807a88d098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:358 [inline] #1: ffff88807a88d098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:377 [inline] #1: ffff88807a88d098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_release+0xd7/0x200 drivers/tty/tty_ldisc.c:802 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729