INFO: task syz.4.2262:12722 blocked for more than 143 seconds. Not tainted 6.6.98-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2262 state:D stack:26824 pid:12722 ppid:10132 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747 sync_bdevs+0x1af/0x330 block/bdev.c:1059 ksys_sync+0xba/0x150 fs/sync.c:105 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f47f598e929 RSP: 002b:00007f47f6784038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f47f5bb5fa0 RCX: 00007f47f598e929 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f47f5bb5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f47f5bb5fa0 R15: 00007fff7145efd8 Showing all locks held in the system: 5 locks held by kworker/1:1/28: #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc90000a4fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90000a4fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff888142fae190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #2: ffff888142fae190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5829 #3: ffff88802db52190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #3: ffff88802db52190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 #4: ffff8880286ff160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #4: ffff8880286ff160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 1 lock held by khungtaskd/29: #0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:6/1129: #0: ffff88801eea0938 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff88801eea0938 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc9000501fd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000501fd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 5 locks held by kworker/u4:7/1767: 2 locks held by getty/5547: #0: ffff88814df000a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015a72f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217 1 lock held by udevd/5775: #0: ffff8880222cb4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788 1 lock held by udevd/5793: #0: ffff8881417264c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788 6 locks held by kworker/0:6/5833: #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc90004a9fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90004a9fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff888142b54190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #2: ffff888142b54190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5829 #3: ffff888064111190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #3: ffff888064111190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 #4: ffff888031bc4160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #4: ffff888031bc4160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 #5: ffffffff8cbda350 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xf0/0x2b0 kernel/umh.c:215 5 locks held by kworker/0:8/5869: #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff8880192de938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc90004b8fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90004b8fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff8880252a3190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #2: ffff8880252a3190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5829 #3: ffff888056673190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #3: ffff888056673190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 #4: ffff888064ed4160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:992 [inline] #4: ffff888064ed4160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x400 drivers/base/dd.c:1005 1 lock held by syz.4.2262/12722: #0: ffff8880222cb4c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1059 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.6.98-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf41/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 16235 Comm: syz.6.3140 Not tainted 6.6.98-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4773 [inline] RIP: 0010:__lock_acquire+0x568/0x7c80 kernel/locking/lockdep.c:5087 Code: 81 e3 ff 1f 00 00 41 c1 ef 03 41 81 e7 f8 03 00 00 49 8d bf 20 65 da 90 be 08 00 00 00 e8 b0 43 77 00 48 0f a3 1d b8 51 73 0f <73> 1f 48 69 c3 d0 00 00 00 48 8d 98 e0 e3 70 90 48 ba 00 00 00 00 RSP: 0018:ffffc900046f7700 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 000000000000098d RCX: ffffffff81671360 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90da6650 RBP: ffffc900046f7948 R08: ffffffff90da6657 R09: 1ffffffff21b4cca R10: dffffc0000000000 R11: fffffbfff21b4ccb R12: ffff8880785d0ac4 R13: ffff8880785d0000 R14: 0000000000000000 R15: 0000000000000130 FS: 0000555590b45500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e21dff8 CR3: 000000004c527000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xa3/0xe0 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline] snd_pcm_stream_lock_irq sound/core/pcm_native.c:136 [inline] snd_pcm_drain+0x7cb/0xd40 sound/core/pcm_native.c:2180 snd_pcm_oss_sync+0xf5/0xc20 sound/core/oss/pcm_oss.c:1730 snd_pcm_oss_release+0x102/0x240 sound/core/oss/pcm_oss.c:2589 __fput+0x234/0x970 fs/file_table.c:384 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6edfd8e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff91ab4868 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f6edffb7ba0 RCX: 00007f6edfd8e929 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f6edffb7ba0 R08: 000000000000245c R09: 0000000991ab4b5f R10: 00000000003fd980 R11: 0000000000000246 R12: 000000000007295d R13: 00007f6edffb6160 R14: ffffffffffffffff R15: 00007fff91ab4980