INFO: task kworker/1:1:23 blocked for more than 140 seconds. Not tainted 4.14.232-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:1 D26568 23 2 0x80000000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 usb_kill_urb.part.0+0x125/0x190 drivers/usb/core/urb.c:691 usb_kill_urb+0x7c/0x90 drivers/usb/core/urb.c:686 usb_start_wait_urb+0x209/0x440 drivers/usb/core/message.c:62 usb_internal_control_msg drivers/usb/core/message.c:100 [inline] usb_control_msg+0x302/0x450 drivers/usb/core/message.c:151 hub_port_init+0xfdc/0x2970 drivers/usb/core/hub.c:4555 hub_port_connect drivers/usb/core/hub.c:4905 [inline] hub_port_connect_change drivers/usb/core/hub.c:5088 [inline] port_event drivers/usb/core/hub.c:5194 [inline] hub_event+0x18fd/0x3d70 drivers/usb/core/hub.c:5274 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Showing all locks held in the system: 5 locks held by kworker/1:1/23: #0: ("usb_hub_wq"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: ((&hub->events)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 #2: (&dev->mutex){....}, at: [] device_lock include/linux/device.h:1081 [inline] #2: (&dev->mutex){....}, at: [] hub_event+0x108/0x3d70 drivers/usb/core/hub.c:5220 #3: (&port_dev->status_lock){+.+.}, at: [] usb_lock_port drivers/usb/core/hub.c:2934 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_port_connect drivers/usb/core/hub.c:4904 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_port_connect_change drivers/usb/core/hub.c:5088 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] port_event drivers/usb/core/hub.c:5194 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_event+0x18e8/0x3d70 drivers/usb/core/hub.c:5274 #4: (hcd->address0_mutex){+.+.}, at: [] hub_port_init+0x15b/0x2970 drivers/usb/core/hub.c:4429 1 lock held by khungtaskd/1533: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by syz-executor.0/1895: #0: (&mm->mmap_sem){++++}, at: [] vm_mmap_pgoff+0x11e/0x1a0 mm/util.c:331 1 lock held by syz-executor.2/1899: #0: (&mm->mmap_sem){++++}, at: [] vm_mmap_pgoff+0x11e/0x1a0 mm/util.c:331 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1533 Comm: khungtaskd Not tainted 4.14.232-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4621 Comm: systemd-journal Not tainted 4.14.232-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a14ea080 task.stack: ffff8880a14f0000 RIP: 0010:validate_chain kernel/locking/lockdep.c:2471 [inline] RIP: 0010:__lock_acquire+0x82c/0x3f20 kernel/locking/lockdep.c:3491 RSP: 0018:ffff8880a14f7710 EFLAGS: 00000046 RAX: 1ffffffff167189b RBX: ffffffff8b38c4c0 RCX: 000000000000407c RDX: 1ffffffff1735fd4 RSI: 000000003d973653 RDI: ffffffff8b38c4d8 RBP: dffffc0000000000 R08: ffffffff8b9afea0 R09: 00000000000e00bc R10: ffff8880a14ea930 R11: ffff8880a14ea080 R12: ffff8880a14ea948 R13: 0000000000000000 R14: 586d2778e7295362 R15: ffffffff8bebbd40 FS: 00007f2b6f6bf8c0(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2b6cadd000 CR3: 00000000a2807000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 seqcount_lockdep_reader_access include/linux/seqlock.h:81 [inline] read_seqcount_begin include/linux/seqlock.h:164 [inline] __follow_mount_rcu+0x249/0x640 fs/namei.c:1354 lookup_fast+0x2ea/0xe30 fs/namei.c:1632 walk_component+0xc0/0xbc0 fs/namei.c:1821 link_path_walk+0x823/0x10a0 fs/namei.c:2154 path_lookupat+0xcb/0x780 fs/namei.c:2342 filename_lookup+0x18a/0x510 fs/namei.c:2377 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:403 [inline] SyS_faccessat+0x21b/0x680 fs/open.c:353 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f2b6e97a9c7 RSP: 002b:00007ffc0efae1e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc0efb1210 RCX: 00007f2b6e97a9c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000056257d0429a3 RBP: 00007ffc0efae330 R08: 000056257d0383e5 R09: 0000000000000018 R10: 00007f2b6ec38b58 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000056257df708a0 R15: 00007ffc0efae820 Code: 54 24 30 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 4b 27 00 00 41 8b 42 20 25 00 80 04 00 3d 00 00 04 00 0f 84 f9 01 00 00 <48> c7 c2 e0 16 3d 89 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03