INFO: task udevd:2842 blocked for more than 143 seconds. Not tainted 6.14.0-rc1-syzkaller-g257a087c8b52 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D running task stack:23552 pid:2842 tgid:2842 ppid:1 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x113d/0x35d0 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913 rwsem_down_read_slowpath+0x61e/0xb20 kernel/locking/rwsem.c:1084 __down_read_common kernel/locking/rwsem.c:1248 [inline] __down_read kernel/locking/rwsem.c:1261 [inline] down_read+0x124/0x330 kernel/locking/rwsem.c:1526 kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1160 d_revalidate fs/namei.c:928 [inline] d_revalidate fs/namei.c:924 [inline] lookup_fast+0x260/0x5f0 fs/namei.c:1754 walk_component+0x5b/0x5b0 fs/namei.c:2110 link_path_walk.part.0.constprop.0+0x669/0xd40 fs/namei.c:2479 link_path_walk fs/namei.c:2410 [inline] path_lookupat+0x93/0x770 fs/namei.c:2635 filename_lookup+0x221/0x5f0 fs/namei.c:2665 do_readlinkat+0xcf/0x390 fs/stat.c:562 __do_sys_readlink fs/stat.c:599 [inline] __se_sys_readlink fs/stat.c:596 [inline] __x64_sys_readlink+0x78/0xc0 fs/stat.c:596 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb36ba39d47 RSP: 002b:00007fff398ba738 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007fff398ba748 RCX: 00007fb36ba39d47 RDX: 0000000000000400 RSI: 00007fff398ba748 RDI: 00007fff398bac28 RBP: 0000000000000400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff398bac28 R13: 00007fff398bab98 R14: 0000563041ac82c0 R15: 0000000000000000 INFO: task udevd:5143 blocked for more than 171 seconds. Not tainted 6.14.0-rc1-syzkaller-g257a087c8b52 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24096 pid:5143 tgid:5143 ppid:2842 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x113d/0x35d0 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730 device_lock include/linux/device.h:1030 [inline] uevent_show+0x188/0x3b0 drivers/base/core.c:2729 dev_attr_show+0x53/0xe0 drivers/base/core.c:2423 sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59 seq_read_iter+0x4f4/0x12b0 fs/seq_file.c:230 kernfs_fop_read_iter+0x414/0x580 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x886/0xbf0 fs/read_write.c:565 ksys_read+0x12b/0x250 fs/read_write.c:708 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb36ba38b6a RSP: 002b:00007fff398b3758 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000563041b015c0 RCX: 00007fb36ba38b6a RDX: 0000000000001000 RSI: 0000563041b816c0 RDI: 0000000000000008 RBP: 0000563041b015c0 R08: 0000000000000008 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007fff398b3c38 R15: 000000000000000a Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff88ebe480 (rcu_read_lock ){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] ){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] ){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 6 locks held by kworker/1:1/41: 1 lock held by udevd/2842: 2 locks held by getty/2902: #0: ffff8881150b00a0 ( &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+0xfba/0x1480 drivers/tty/n_tty.c:2211 4 locks held by udevd/5143: #0: ffff888113b2e0a0 ( &p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182 #1: ffff88811a4cfc88 ( &of->mutex#2 ){+.+.}-{4:4} , at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff8881194db3c8 ( kn->active #3 ){++++}-{0:0} , at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff88810ab0c190 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:1030 [inline] , at: uevent_show+0x188/0x3b0 drivers/base/core.c:2729 5 locks held by kworker/0:3/5223: #0: ffff8881062fb548 ((wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000200fd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffff88810b7cd190 (&dev->mutex ){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline] ){....}-{4:4}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5851 #3: ffff888117878190 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1030 [inline] #3: ffff888117878190 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x920 drivers/usb/core/hub.c:2296 #4: ffff888100abc148 (&root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_find_and_get_ns+0x71/0xc0 fs/kernfs/dir.c:918 3 locks held by kworker/1:3/5227: #0: ffff888100080d48 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000202fd18 ( (work_completion)(&gadget->work) ){+.+.}-{0:0} , at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffff888100abc148 (&root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_find_and_get_ns+0x71/0xc0 fs/kernfs/dir.c:918 1 lock held by udevd/5324: 6 locks held by kworker/1:6/13099: 3 locks held by kworker/0:1/15610: 1 lock held by syz-executor/16042: 3 locks held by kworker/1:0/18323: 4 locks held by kworker/u8:1/22256: #0: ffff888100abb148 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90001d2fd18 ( net_cleanup_work ){+.+.}-{0:0} , at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffffffff8a189790 (pernet_ops_rwsem){++++}-{4:4} , at: cleanup_net+0xca/0xbf0 net/core/net_namespace.c:606 #3: ffffffff88ec98f8 (rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:334 1 lock held by syz-executor/22426: 1 lock held by syz-executor/23254: 1 lock held by syz.8.4572/24207: #0: ffff888100abc148 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_remove_by_name_ns+0x87/0x130 fs/kernfs/dir.c:1690 1 lock held by syz.6.4577/24220: #0: ffff888100abc148 (&root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_remove_by_name_ns+0x87/0x130 fs/kernfs/dir.c:1690 1 lock held by syz-executor/24223: #0: ffff888100abc148 (&root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1160 1 lock held by syz-executor/24224: #0: ffff888100abc148 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1160 1 lock held by syz-executor/24225: #0: ffff888100abc148 ( &root->kernfs_rwsem ){++++}-{4:4} , at: kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1160 1 lock held by syz-executor/24226: #0: ffff888100abc148 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1160 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc1-syzkaller-g257a087c8b52 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 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:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0xf62/0x12b0 kernel/hung_task.c:399 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: yealink 2-1:36.0: urb_ctl_callback - urb status -71 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5263 Comm: kworker/1:5 Not tainted 6.14.0-rc1-syzkaller-g257a087c8b52 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: events dvb_usb_read_remote_control RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:416 Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 81 71 0c ff eb a0 e8 0a 72 0c RSP: 0000:ffffc900001b8500 EFLAGS: 00000002 RAX: 0000000000000038 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff82c8ccd5 RDI: ffffffff9366a2a0 RBP: ffffffff9366a260 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000006 R12: 0000000000000000 R13: 0000000000000038 R14: ffffffff9366a260 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f5900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e55ffff CR3: 0000000119e80000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_port_out include/linux/serial_core.h:796 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3306 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline] serial8250_console_write+0xfb1/0x1870 drivers/tty/serial/8250/8250_port.c:3456 console_emit_next_record kernel/printk/printk.c:3122 [inline] console_flush_all+0x800/0xc60 kernel/printk/printk.c:3210 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline] console_unlock+0xd9/0x210 kernel/printk/printk.c:3309 vprintk_emit+0x424/0x6f0 kernel/printk/printk.c:2432 dev_vprintk_emit drivers/base/core.c:4890 [inline] dev_printk_emit+0xfb/0x140 drivers/base/core.c:4901 __dev_printk+0xf5/0x270 drivers/base/core.c:4913 _dev_err+0xe5/0x120 drivers/base/core.c:4956 urb_ctl_callback+0x1eb/0x2f0 drivers/input/misc/yealink.c:456 __usb_hcd_giveback_urb+0x389/0x6e0 drivers/usb/core/hcd.c:1650 usb_hcd_giveback_urb+0x396/0x450 drivers/usb/core/hcd.c:1734 dummy_timer+0x17f7/0x3960 drivers/usb/gadget/udc/dummy_hcd.c:1994 __run_hrtimer kernel/time/hrtimer.c:1738 [inline] __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1802 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1819 handle_softirqs+0x206/0x8d0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xfa/0x160 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 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_flush_all+0x9a4/0xc60 kernel/printk/printk.c:3211 Code: 00 e8 70 9d 27 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 6e ed 1f 00 48 85 db 0f 85 55 01 00 00 e8 30 f2 1f 00 fb 4c 89 e0 <48> c1 e8 03 42 80 3c 38 00 0f 84 11 ff ff ff 4c 89 e7 e8 c5 02 7a RSP: 0000:ffffc900021478c0 EFLAGS: 00000293 RAX: ffffffff893ac398 RBX: 0000000000000000 RCX: ffffffff815b3c32 RDX: ffff88811fdfba80 RSI: ffffffff815b3c40 RDI: 0000000000000007 RBP: 0000000000000001 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000005 R12: ffffffff893ac398 R13: ffffffff893ac340 R14: ffffc90002147950 R15: dffffc0000000000 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline] console_unlock+0xd9/0x210 kernel/printk/printk.c:3309 vprintk_emit+0x424/0x6f0 kernel/printk/printk.c:2432 _printk+0xc8/0x100 kernel/printk/printk.c:2457 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline] m920x_rc_core_query+0x2d7/0x500 drivers/media/usb/dvb-usb/m920x.c:229 dvb_usb_read_remote_control+0xda/0x1c0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:261 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244