INFO: task syz.3.608:7724 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.608 state:D stack:28520 pid:7724 tgid:7722 ppid:5808 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760 bdev_open+0xa2/0xe40 block/bdev.c:945 bdev_file_open_by_dev block/bdev.c:1059 [inline] bdev_file_open_by_dev+0x182/0x210 block/bdev.c:1034 setup_bdev_super+0x39b/0x730 fs/super.c:1609 get_tree_bdev_flags+0x363/0x620 fs/super.c:1689 vfs_get_tree+0x8e/0x340 fs/super.c:1751 fc_mount fs/namespace.c:1208 [inline] do_new_mount_fc fs/namespace.c:3651 [inline] do_new_mount fs/namespace.c:3727 [inline] path_mount+0x7b9/0x23a0 fs/namespace.c:4037 do_mount fs/namespace.c:4050 [inline] __do_sys_mount fs/namespace.c:4238 [inline] __se_sys_mount fs/namespace.c:4215 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4215 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fce1638eec9 RSP: 002b:00007fce17267038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fce165e6090 RCX: 00007fce1638eec9 RDX: 0000200000000080 RSI: 0000200000000040 RDI: 00002000000000c0 RBP: 00007fce16411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fce165e6128 R14: 00007fce165e6090 R15: 00007ffff54d7088 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 5 locks held by kworker/0:2/848: #0: ffff8880216ce948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc900033d7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff888029763198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff888029763198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fe0 drivers/usb/core/hub.c:5898 #3: ffff888074c1d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #3: ffff888074c1d198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff8880473b7160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff8880473b7160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 3 locks held by kworker/u9:1/5131: #0: ffff888054cc2948 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000fb9fd00 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff88805744cdc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_open+0x22/0x90 net/bluetooth/hci_core.c:428 2 locks held by syslogd/5162: #0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline] #0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631 #1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline] #1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6923 3 locks held by acpid/5165: #0: ffff8880473b2160 (&mousedev->mutex#2){+.+.}-{4:4}, at: mousedev_close_device+0x21/0xd0 drivers/input/mousedev.c:441 #1: ffff888074c192c0 (&dev->mutex#2){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:228 [inline] #1: ffff888074c192c0 (&dev->mutex#2){+.+.}-{4:4}, at: input_close_device+0x46/0x2a0 drivers/input/input.c:646 #2: ffffffff8e3cfa38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 1 lock held by klogd/5169: 2 locks held by getty/5561: #0: ffff8880321c40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 no locks held by syz-executor/5807. 5 locks held by kworker/0:3/5885: #0: ffff8880216ce948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc9000448fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff888144ff3198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff888144ff3198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fe0 drivers/usb/core/hub.c:5898 #3: ffff888031b57198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #3: ffff888031b57198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 #4: ffff88802a574160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff88802a574160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006 6 locks held by kworker/0:6/5926: #0: ffff8880216ce948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc90004e6fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff888144f20198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff888144f20198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fe0 drivers/usb/core/hub.c:5898 #3: ffff88807a298198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #3: ffff88807a298198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2335 #4: ffff888074c1b160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff888074c1b160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline] #4: ffff888074c1b160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294 #5: ffff888074c192c0 (&dev->mutex#2){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:228 [inline] #5: ffff888074c192c0 (&dev->mutex#2){+.+.}-{4:4}, at: input_disconnect_device drivers/input/input.c:703 [inline] #5: ffff888074c192c0 (&dev->mutex#2){+.+.}-{4:4}, at: __input_unregister_device+0x24/0x4d0 drivers/input/input.c:2185 1 lock held by udevd/6046: #0: ffff8880269af358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945 2 locks held by syz.3.608/7724: #0: ffff888074a4c0e0 (&type->s_umount_key#74/1){+.+.}-{4:4}, at: alloc_super+0x1e3/0xb60 fs/super.c:344 #1: ffff8880269af358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xa2/0xe40 block/bdev.c:945 2 locks held by syz.8.1159/9381: #0: ffff888030bf9470 (&fc->uapi_mutex){+.+.}-{4:4}, at: __do_sys_fsconfig+0x745/0xbe0 fs/fsopen.c:471 #1: ffffffff8e3cfa38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz.8.1159/9384: #0: ffff888030bf9870 (&fc->uapi_mutex){+.+.}-{4:4}, at: __do_sys_fsconfig+0x745/0xbe0 fs/fsopen.c:471 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf3f/0x1170 kernel/hung_task.c:495 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x672/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5793 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319 Code: 00 00 00 eb b6 e8 30 fa ff ff eb b6 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 8b 05 46 f9 1d 05 85 c0 74 20 8b 05 d0 28 1e 05 85 c0 RSP: 0018:ffffc90002f47970 EFLAGS: 00000282 RAX: fffff520005e8f31 RBX: 1ffff920005e8f31 RCX: ffffffff93b2c860 RDX: 0000000000000000 RSI: 0000000000000e8a RDI: ffffffff8cbf2f80 RBP: 0000000000000000 R08: dc34619114e306ce R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8cbf2f80 R13: 0000000000000e8a R14: ffffc90002f47a78 R15: 0000000000000000 FS: 000055558433d500(0000) GS:ffff888124add000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f072f28ff98 CR3: 0000000076c9f000 CR4: 00000000003526f0 Call Trace: __might_resched+0x5d/0x5e0 kernel/sched/core.c:8887 lock_sock_nested+0x52/0xf0 net/core/sock.c:3722 lock_sock include/net/sock.h:1679 [inline] tcp_recvmsg+0x115/0x680 net/ipv4/tcp.c:2927 inet_recvmsg+0x129/0x6a0 net/ipv4/af_inet.c:885 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x1b2/0x250 net/socket.c:1100 sock_read_iter+0x2b9/0x3b0 net/socket.c:1170 new_sync_read fs/read_write.c:491 [inline] vfs_read+0xa98/0xcf0 fs/read_write.c:572 ksys_read+0x1f8/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc6a0f8d89d Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d c1 ac 22 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec RSP: 002b:00007fff9bb55fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc6a0f8d89d RDX: 0000000000000004 RSI: 00007fff9bb55fdc RDI: 0000000000000003 RBP: 0000000000000000 R08: 00000000000116ee R09: 00007fc6a1ddf000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff9bb563f0 R13: 0000000000000004 R14: 00007fff9bb55fdc R15: 00007fff9bb56070