INFO: task kworker/0:0:9 blocked for more than 143 seconds. Not tainted syzkaller #0 Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0 state:D stack:21960 pid:9 tgid:9 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_freezable mmc_rescan Call Trace: context_switch kernel/sched/core.c:5526 [inline] __schedule+0x1325/0x47e0 kernel/sched/core.c:7276 __schedule_loop kernel/sched/core.c:7353 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7368 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121 mmc_wait_for_req_done+0xcd/0x3d0 drivers/mmc/core/core.c:408 mmc_wait_for_req+0x207/0x2c0 drivers/mmc/core/core.c:619 mmc_wait_for_cmd+0x154/0x200 drivers/mmc/core/core.c:645 __mmc_send_if_cond drivers/mmc/core/sd_ops.c:232 [inline] mmc_send_if_cond_pcie+0x144/0x370 drivers/mmc/core/sd_ops.c:269 mmc_rescan_try_freq drivers/mmc/core/core.c:2126 [inline] mmc_rescan+0xbf3/0x11c0 drivers/mmc/core/core.c:2316 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task kworker/0:2:121 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:2 state:D stack:20640 pid:121 tgid:121 ppid:2 task_flags:0x4288060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5526 [inline] __schedule+0x1325/0x47e0 kernel/sched/core.c:7276 __schedule_loop kernel/sched/core.c:7353 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7368 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121 __flush_work+0x7c7/0xcb0 kernel/workqueue.c:4448 __cancel_work_sync kernel/workqueue.c:4568 [inline] cancel_delayed_work_sync+0xd1/0xf0 kernel/workqueue.c:4642 __mmc_stop_host drivers/mmc/core/core.c:2368 [inline] __mmc_stop_host drivers/mmc/core/core.c:2357 [inline] mmc_stop_host+0xe9/0x400 drivers/mmc/core/core.c:2373 mmc_remove_host+0x15/0x60 drivers/mmc/core/host.c:681 vub300_disconnect+0x12d/0x170 drivers/mmc/host/vub300.c:2387 usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:618 [inline] device_remove+0x12a/0x180 drivers/base/dd.c:610 __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664 device_del+0x376/0x9b0 drivers/base/core.c:3965 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2350 hub_port_connect drivers/usb/core/hub.c:5420 [inline] hub_port_connect_change drivers/usb/core/hub.c:5720 [inline] port_event drivers/usb/core/hub.c:5884 [inline] hub_event+0x1d46/0x4510 drivers/usb/core/hub.c:5966 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: locks held by kworker/0:0/9: 2, on CPU#0: #0: ffff88810006a140 ((wq_completion)events_freezable){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371 #1: ffffc9000009fd18 ((work_completion)(&(&host->detect)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372 locks held by pr/ttyS0/15: 2, last CPU#0: #0: ffffffff898d0ef8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline] #0: ffffffff898d0ef8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline] #0: ffffffff898d0ef8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x49/0x60 kernel/printk/printk.c:291 #1: ffffffff9448c7f8 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline] #1: ffffffff9448c7f8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x64/0xc0 drivers/tty/serial/8250/8250_core.c:413 locks held by khungtaskd/30: 1, last CPU#1: #0: ffffffff898e4c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff898e4c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff898e4c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871 locks held by kworker/0:2/121: 5, on CPU#0: #0: ffff888102ac7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371 #1: ffffc90001527d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372 #2: ffff88810ab151d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88810ab151d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4510 drivers/usb/core/hub.c:5912 #3: ffff888121c741d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #3: ffff888121c741d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2341 #4: ffff888121c721a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #4: ffff888121c721a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline] #4: ffff888121c721a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369 locks held by getty/2924: 2, on CPU#0: #0: ffff888113dd30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000452e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 locks held by kworker/1:6/5284: 5, on CPU#1: #0: ffff888102ac7d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371 #1: ffffc9000275fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372 #2: ffff88810a3cd1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88810a3cd1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4510 drivers/usb/core/hub.c:5912 #3: ffff88810a37a560 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3265 [inline] #3: ffff88810a37a560 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5477 [inline] #3: ffff88810a37a560 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline] #3: ffff88810a37a560 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline] #3: ffff88810a37a560 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2c08/0x4510 drivers/usb/core/hub.c:5966 #4: ffff88810a31bc60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5478 [inline] #4: ffff88810a31bc60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline] #4: ffff88810a31bc60 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline] #4: ffff88810a31bc60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2c31/0x4510 drivers/usb/core/hub.c:5966 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 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: 15 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:preempt_count_sub+0x4b/0x150 kernel/sched/core.c:6035 Code: 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 d6 00 00 00 8b 0d 95 67 ad 12 85 c9 75 14 65 48 8b 05 31 6b a0 0b 39 d8 72 1b <81> fb fe 00 00 00 76 6f f7 db 48 63 db 65 48 01 1d 18 6b a0 0b 5b RSP: 0018:ffffc900000ff978 EFLAGS: 00000002 RAX: 8000000000000003 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000004 RDI: 0000000000000001 RBP: 0000000000000006 R08: 0000000000000000 R09: fffffbfff287c35a R10: ffffffff943e1ad3 R11: 0000000000000000 R12: 0000000000000005 R13: ffff8881f563ab20 R14: ffffffff87ad6460 R15: 1ffff9200001ff38 FS: 0000000000000000(0000) GS:ffff8882683e2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2edfaff8 CR3: 000000012dd36000 CR4: 00000000003506f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline] _raw_spin_unlock_irqrestore+0x3b/0x80 kernel/locking/spinlock.c:221 debug_object_assert_init+0x1c4/0x310 lib/debugobjects.c:1072 debug_hrtimer_assert_init kernel/time/hrtimer.c:496 [inline] hrtimer_start_range_ns+0x4e/0x460 kernel/time/hrtimer.c:1526 hrtimer_start include/linux/hrtimer.h:222 [inline] hrtick_cond_restart kernel/sched/core.c:949 [inline] hrtick_schedule_exit kernel/sched/core.c:1011 [inline] finish_lock_switch kernel/sched/core.c:5256 [inline] finish_task_switch.isra.0+0x69e/0xad0 kernel/sched/core.c:5375 context_switch kernel/sched/core.c:5529 [inline] __schedule+0x132d/0x47e0 kernel/sched/core.c:7276 preempt_schedule_common+0x3c/0xb0 kernel/sched/core.c:7455 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:221 nbcon_emit_one+0x15c/0x2b0 kernel/printk/nbcon.c:1165 nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245