INFO: task udevd:13605 blocked for more than 143 seconds. Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24536 pid:13605 tgid:13605 ppid:2843 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x132a/0x3b00 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 device_lock include/linux/device.h:922 [inline] uevent_show+0x187/0x3b0 drivers/base/core.c:2730 dev_attr_show+0x53/0xe0 drivers/base/core.c:2424 sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65 seq_read_iter+0x506/0x12c0 fs/seq_file.c:230 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x8c8/0xc70 fs/read_write.c:570 ksys_read+0x12a/0x240 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f949a1e3b6a RSP: 002b:00007ffc4db90388 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00005562393ae980 RCX: 00007f949a1e3b6a RDX: 0000000000001000 RSI: 00005562393a9f10 RDI: 0000000000000008 RBP: 00005562393ae980 R08: 0000000000000008 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007ffc4db90868 R15: 000000000000000a Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff890c2840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff890c2840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff890c2840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 2 locks held by getty/2901: #0: ffff8881121870a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock ){+.+.}-{4:4} , at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 5 locks held by kworker/0:2/8837: 1 lock held by syz-executor/10406: 1 lock held by syz-executor/10414: 4 locks held by udevd/13605: #0: ffff888119c6e540 (&p->lock){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 #1: ffff88811eeca088 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff888109350008 (kn->active){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff88810b7c3198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff88810b7c3198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x187/0x3b0 drivers/base/core.c:2730 5 locks held by kworker/0:9/17815: #0: ffff8881066d9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000208fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffff88810bb29198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] ffff88810bb29198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5030 drivers/usb/core/hub.c:5863 #3: ffff888118d45198 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] &dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1005 #4: ffff888109336c68 (hcd->bandwidth_mutex ){+.+.}-{4:4}, at: usb_set_configuration+0x616/0x1e20 drivers/usb/core/message.c:2077 3 locks held by kworker/u8:1/18358: #0: ffff888100ac3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90001aafd18 ( net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff8a39fbd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 6 locks held by kworker/1:2/19465: 3 locks held by kworker/1:3/19849: 3 locks held by kworker/0:13/21536: 1 lock held by syz.7.5260/27403: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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: 21103 Comm: kworker/0:0 Not tainted 6.15.0-rc1-syzkaller-00097-g3baea29dc0a7 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events legacy_dvb_usb_read_remote_control RIP: 0010:dummy_timer+0x261/0x3a20 drivers/usb/gadget/udc/dummy_hcd.c:1831 Code: 8e 69 2b 00 00 4c 89 fa 83 c3 01 bf 19 00 00 00 48 83 c5 10 48 c1 e2 04 89 de 49 83 c4 78 4c 29 fa 41 80 a4 d6 b0 00 00 00 fb ea db 94 fc 83 fb 19 74 2b e8 a0 e0 94 fc 4c 63 fb 49 83 ff 18 RSP: 0018:ffffc90000007be8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 000000000000000e RCX: ffffffff84e78806 RDX: 00000000000000c3 RSI: 000000000000000e RDI: 0000000000000019 RBP: ffffffff87d532c0 R08: 0000000000000005 R09: 0000000000000019 R10: 000000000000000d R11: 0000000000000000 R12: ffff88810af38740 R13: dffffc0000000000 R14: ffff88810af38000 R15: 000000000000000d FS: 0000000000000000(0000) GS:ffff8882691c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fea9e5ac440 CR3: 0000000135842000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x1ff/0xad0 kernel/time/hrtimer.c:1825 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1842 handle_softirqs+0x205/0x8d0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xfa/0x160 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline] RIP: 0010:vprintk_emit+0x567/0x6d0 kernel/printk/printk.c:2449 Code: 00 4d 85 ed 0f 85 19 01 00 00 e8 94 dd 1f 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 f2 d8 1f 00 48 85 ed 0f 85 25 01 00 00 74 dd 1f 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00 RSP: 0018:ffffc9000dd2f9f0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000017 RCX: ffffffff815c8c4c RDX: ffff88813cf4ba80 RSI: ffffffff815c8c56 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92001ba5f40 R13: 0000000000000200 R14: ffff888101edba80 R15: ffffc9000dd2fab8 _printk+0xc7/0x100 kernel/printk/printk.c:2475 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline] m920x_rc_query+0x496/0x770 drivers/media/usb/dvb-usb/m920x.c:193 legacy_dvb_usb_read_remote_control+0x109/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245