syzbot


INFO: task hung in con_flush_chars (3)

Status: auto-closed as invalid on 2021/12/18 10:46
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 440d, last: 440d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in con_flush_chars (2) 2 766d 839d 0/24 auto-closed as invalid on 2021/01/25 20:43
upstream INFO: task hung in con_flush_chars 1 962d 962d 0/24 auto-closed as invalid on 2020/07/13 22:15
linux-4.14 INFO: task hung in con_flush_chars 2 998d 1014d 0/1 auto-closed as invalid on 2020/07/08 07:44

Sample crash report:
INFO: task kworker/u4:5:3231 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5    state:D stack:24488 pid: 3231 ppid:     2 flags:0x00004000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857
 __down_common+0x2e0/0x420 kernel/locking/semaphore.c:224
 down+0x72/0xa0 kernel/locking/semaphore.c:62
 console_lock+0x2a/0x80 kernel/printk/printk.c:2523
 con_flush_chars drivers/tty/vt/vt.c:3365 [inline]
 con_flush_chars+0x35/0x90 drivers/tty/vt/vt.c:3357
 __receive_buf drivers/tty/n_tty.c:1581 [inline]
 n_tty_receive_buf_common+0x16f9/0x4780 drivers/tty/n_tty.c:1674
 tty_ldisc_receive_buf+0xa3/0x190 drivers/tty/tty_buffer.c:471
 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:491 [inline]
 flush_to_ldisc+0x20d/0x380 drivers/tty/tty_buffer.c:543
 process_one_work+0x9bf/0x1620 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3c2/0x4a0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
INFO: task kworker/0:8:13169 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:8     state:D stack:21872 pid:13169 ppid:     2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 schedule_preempt_disabled+0xc/0x20 kernel/sched/core.c:6425
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa08/0x12b0 kernel/locking/mutex.c:729
 exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 synchronize_rcu_expedited+0x2fb/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_disconnect+0x8b/0xb0 drivers/input/evdev.c:1409
 __input_unregister_device+0x206/0x470 drivers/input/input.c:2189
 input_unregister_device+0xb4/0xf0 drivers/input/input.c:2379
 hidinput_disconnect+0x15e/0x3d0 drivers/hid/hid-input.c:2038
 hid_disconnect+0x13f/0x1a0 drivers/hid/hid-core.c:2032
 hid_hw_stop drivers/hid/hid-core.c:2079 [inline]
 hid_device_remove+0x15d/0x200 drivers/hid/hid-core.c:2318
 __device_release_driver+0x3bd/0x700 drivers/base/dd.c:1203
 device_release_driver_internal drivers/base/dd.c:1236 [inline]
 device_release_driver+0x26/0x40 drivers/base/dd.c:1259
 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
 device_del+0x502/0xd60 drivers/base/core.c:3546
 hid_remove_device drivers/hid/hid-core.c:2485 [inline]
 hid_destroy_device+0xe1/0x150 drivers/hid/hid-core.c:2504
 usbhid_disconnect+0x9f/0xe0 drivers/hid/usbhid/hid-core.c:1451
 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
 __device_release_driver+0x5d7/0x700 drivers/base/dd.c:1205
 device_release_driver_internal drivers/base/dd.c:1236 [inline]
 device_release_driver+0x26/0x40 drivers/base/dd.c:1259
 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
 device_del+0x502/0xd60 drivers/base/core.c:3546
 usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
 usb_disconnect.cold+0x27a/0x78e drivers/usb/core/hub.c:2225
 hub_port_connect drivers/usb/core/hub.c:5199 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5488 [inline]
 port_event drivers/usb/core/hub.c:5634 [inline]
 hub_event+0x1c9c/0x4330 drivers/usb/core/hub.c:5716
 process_one_work+0x9bf/0x1620 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3c2/0x4a0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
INFO: task login:20991 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:login           state:D stack:28312 pid:20991 ppid:     1 flags:0x00004002
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 rwsem_down_write_slowpath+0x8e3/0x1190 kernel/locking/rwsem.c:1107
 __down_write_common kernel/locking/rwsem.c:1262 [inline]
 __down_write_common kernel/locking/rwsem.c:1259 [inline]
 __down_write kernel/locking/rwsem.c:1271 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1518
 n_tty_flush_buffer+0x1d/0x230 drivers/tty/n_tty.c:369
 tty_ldisc_hangup+0xc5/0x680 drivers/tty/tty_ldisc.c:719
 __tty_hangup.part.0+0x40a/0x830 drivers/tty/tty_io.c:639
 __tty_hangup drivers/tty/tty_io.c:594 [inline]
 tty_vhangup_session+0x20/0x30 drivers/tty/tty_io.c:747
 disassociate_ctty.part.0+0xaf/0x790 drivers/tty/tty_jobctrl.c:275
 disassociate_ctty+0x7a/0x90 drivers/tty/tty_jobctrl.c:269
 do_exit+0x1907/0x2890 kernel/exit.c:823
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x47f/0x2170 kernel/signal.c:2868
 arch_do_signal_or_restart+0x2a9/0x1c10 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x15d/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4315a38970
RSP: 002b:00007ffcbaa4e358 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: fffffffffffffe00 RBX: 000000000000000a RCX: 00007f4315a38970
RDX: 000000000000000a RSI: 0000564c07580af0 RDI: 0000000000000002
RBP: 0000564c07580af0 R08: 00007f43165534c0 R09: 00007ffcbaa4e4b0
R10: 0000000000000449 R11: 0000000000000246 R12: 000000000000000a
R13: 0000000000000001 R14: 00007f4315cf7520 R15: 000000000000000a
INFO: task syz-executor.3:3086 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:28472 pid: 3086 ppid:  3224 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x5d2/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_detach_client drivers/input/evdev.c:386 [inline]
 evdev_release+0x23f/0x410 drivers/input/evdev.c:449
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbae/0x2890 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x47f/0x2170 kernel/signal.c:2868
 arch_do_signal_or_restart+0x2a9/0x1c10 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x15d/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcba95284f7
RSP: 002b:00007fcba725c0b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 00007fcba725d130 RCX: 00007fcba95284f7
RDX: 00007fcba725d130 RSI: 0000000080085502 RDI: 0000000000000005
RBP: 0000000000000005 R08: 000000000000ffff R09: 000000000000000b
R10: 00007fcba725c180 R11: 0000000000000246 R12: 0000000800000000
R13: 0000000000000000 R14: 0000000020000140 R15: 00007fcba958e0c6
INFO: task syz-executor.1:3054 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:28824 pid: 3054 ppid:  8389 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 synchronize_rcu_expedited+0x499/0x640 kernel/rcu/tree_exp.h:853
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_detach_client drivers/input/evdev.c:386 [inline]
 evdev_release+0x23f/0x410 drivers/input/evdev.c:449
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x215/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f9c825dc54b
RSP: 002b:00007fffed77d830 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f9c825dc54b
RDX: 00007f9c82732710 RSI: 0000000000000080 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007fffed77d920 R11: 0000000000000293 R12: 00000000003298e6
R13: 00000000000003e8 R14: 00007f9c8272df80 R15: 000000000032982a
INFO: task syz-executor.4:3072 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28824 pid: 3072 ppid: 26132 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x5d2/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_detach_client drivers/input/evdev.c:386 [inline]
 evdev_release+0x23f/0x410 drivers/input/evdev.c:449
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x215/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcabf5c154b
RSP: 002b:00007fff7784fcd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007fcabf5c154b
RDX: 0000001b2c73fb7c RSI: ffffffff8202732e RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b2c73d1bc
R10: 000000000000198e R11: 0000000000000293 R12: 00007fcabf713b00
R13: 00007fcabf713b00 R14: 00007fcabf712f80 R15: 00000000003299bc
INFO: task syz-executor.4:3073 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28344 pid: 3073 ppid: 26132 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x5d2/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_detach_client drivers/input/evdev.c:386 [inline]
 evdev_release+0x23f/0x410 drivers/input/evdev.c:449
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x215/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fcabf5c1824
RSP: 002b:00007fcabd385cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffea RBX: 6666666666666667 RCX: 00007fcabf5c1824
RDX: 0000000000026a41 RSI: 00007fcabd385d60 RDI: 00000000ffffff9c
RBP: 00007fcabd385d60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000026a41
R13: 00007fff7784fc6f R14: 00007fcabd386300 R15: 0000000000022000
INFO: task syz-executor.2:3082 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:28824 pid: 3082 ppid:  3099 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x5d2/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 evdev_detach_client drivers/input/evdev.c:386 [inline]
 evdev_release+0x23f/0x410 drivers/input/evdev.c:449
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x215/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f0fdc73754b
RSP: 002b:00007ffd16693b00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f0fdc73754b
RDX: 00007f0fdc88d898 RSI: ffffffff85c2ec88 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b336277f8
R10: 0000000000001f4e R11: 0000000000000293 R12: 0000000000329ecd
R13: 00000000000003e8 R14: 00007f0fdc888f80 R15: 0000000000329ae5
INFO: task syz-executor.5:3108 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:26272 pid: 3108 ppid:  3692 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x5d2/0x640 kernel/rcu/tree_exp.h:837
 synchronize_rcu+0x154/0x1b0 kernel/rcu/tree.c:3746
 rcu_sync_enter+0x147/0x2e0 kernel/rcu/sync.c:149
 percpu_down_write+0x57/0x3e0 kernel/locking/percpu-rwsem.c:220
 ext4_ind_migrate+0x237/0x840 fs/ext4/migrate.c:623
 ext4_ioctl_setflags fs/ext4/ioctl.c:456 [inline]
 ext4_fileattr_set+0x1455/0x18b0 fs/ext4/ioctl.c:762
 vfs_fileattr_set+0x76e/0xb70 fs/ioctl.c:700
 ioctl_fssetxattr fs/ioctl.c:762 [inline]
 do_vfs_ioctl+0xe71/0x15d0 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x108/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f76a5c47739
RSP: 002b:00007f76a39bf188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f76a5d4bf80 RCX: 00007f76a5c47739
RDX: 0000000020000080 RSI: 0000000040086602 RDI: 0000000000000007
RBP: 00007f76a5ca1cc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f76a5d4bf80
R13: 00007ffd30f2d32f R14: 00007f76a39bf300 R15: 0000000000022000
INFO: task syz-executor.5:3109 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:28600 pid: 3109 ppid:  3692 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0x947/0x22b0 kernel/sched/core.c:6287
 schedule+0xcf/0x270 kernel/sched/core.c:6366
 rwsem_down_write_slowpath+0x8e3/0x1190 kernel/locking/rwsem.c:1107
 __down_write_common kernel/locking/rwsem.c:1262 [inline]
 __down_write_common kernel/locking/rwsem.c:1259 [inline]
 __down_write kernel/locking/rwsem.c:1271 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1518
 inode_lock include/linux/fs.h:786 [inline]
 process_measurement+0x17c0/0x1920 security/integrity/ima/ima_main.c:241
 ima_file_check+0xb1/0x100 security/integrity/ima/ima_main.c:516
 do_open fs/namei.c:3430 [inline]
 path_openat+0x1643/0x2740 fs/namei.c:3561
 do_filp_open+0x1aa/0x400 fs/namei.c:3588
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200
 do_sys_open fs/open.c:1216 [inline]
 __do_sys_openat fs/open.c:1232 [inline]
 __se_sys_openat fs/open.c:1227 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f76a5bfa824
RSP: 002b:00007f76a399dcc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007f76a5bfa824
RDX: 0000000000000000 RSI: 00007f76a399dd60 RDI: 00000000ffffff9c
RBP: 00007f76a399dd60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffd30f2d32f R14: 00007f76a399e300 R15: 0000000000022000

Showing all locks held in the system:
6 locks held by kworker/1:0/17:
1 lock held by khungtaskd/23:
 #0: ffffffff87681ea0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6446
3 locks held by rs:main Q:Reg/2814:
5 locks held by kworker/u4:5/3231:
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888100069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x8a3/0x1620 kernel/workqueue.c:2268
 #1: ffffc9000137fdb0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x1620 kernel/workqueue.c:2272
 #2: ffff888115fa80b8 (&buf->lock){+.+.}-{3:3}, at: flush_to_ldisc+0x3e/0x380 drivers/tty/tty_buffer.c:515
 #3: ffff88814eef9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273
 #4: ffff88814eef92e8 (&tty->termios_rwsem){++++}-{3:3}, at: isig+0x37d/0x430 drivers/tty/n_tty.c:1149
6 locks held by kworker/0:4/5465:
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x8a3/0x1620 kernel/workqueue.c:2268
 #1: ffffc900022f7db0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x1620 kernel/workqueue.c:2272
 #2: ffff88810ce9b220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #2: ffff88810ce9b220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4330 drivers/usb/core/hub.c:5662
 #3: ffff88811152c220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #3: ffff88811152c220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
 #4: ffff88810dc171a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #4: ffff88810dc171a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7a/0x4a0 drivers/base/dd.c:944
 #5: ffffffff88138048 (input_mutex){+.+.}-{3:3}, at: input_register_device.cold+0x34/0x304 drivers/input/input.c:2328
6 locks held by kworker/1:7/6616:
8 locks held by kworker/0:8/13169:
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline]
 #0: ffff888103386938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x8a3/0x1620 kernel/workqueue.c:2268
 #1: ffffc900012afdb0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x1620 kernel/workqueue.c:2272
 #2: ffff88810ce33220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #2: ffff88810ce33220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c1/0x4330 drivers/usb/core/hub.c:5662
 #3: ffff88810bcd9220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #3: ffff88810bcd9220 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x78e drivers/usb/core/hub.c:2216
 #4: ffff88810bcdf1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #4: ffff88810bcdf1a8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
 #4: ffff88810bcdf1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
 #4: ffff88810bcdf1a8 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
 #5: ffff8881550a9ab0 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #5: ffff8881550a9ab0 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1032 [inline]
 #5: ffff8881550a9ab0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal drivers/base/dd.c:1233 [inline]
 #5: ffff8881550a9ab0 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 drivers/base/dd.c:1259
 #6: ffffffff88138048 (input_mutex){+.+.}-{3:3}, at: __input_unregister_device+0x16d/0x470 drivers/input/input.c:2186
 #7: ffffffff876889e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #7: ffffffff876889e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2fb/0x640 kernel/rcu/tree_exp.h:837
2 locks held by agetty/10276:
 #0: ffff888102dc9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000ffcb2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
3 locks held by kworker/1:6/1634:
3 locks held by login/20991:
 #0: ffff88814eef91c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:20
 #1: ffff88814eef9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:273 [inline]
 #1: ffff88814eef9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_hangup+0x2c/0x680 drivers/tty/tty_ldisc.c:716
 #2: ffff88814eef92e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_flush_buffer+0x1d/0x230 drivers/tty/n_tty.c:369
1 lock held by syz-executor.1/3054:
 #0: ffffffff876889e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #0: ffffffff876889e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2fb/0x640 kernel/rcu/tree_exp.h:837
3 locks held by systemd-udevd/3075:
 #0: ffff8881111cdc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:203 [inline]
 #0: ffff8881111cdc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x185/0x5f0 fs/kernfs/file.c:242
 #1: ffff88810dbed830 (kn->active#99){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:204 [inline]
 #1: ffff88810dbed830 (kn->active#99){++++}-{0:0}, at: kernfs_fop_read_iter+0x1a8/0x5f0 fs/kernfs/file.c:242
 #2: ffff88811152c220 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:765 [inline]
 #2: ffff88811152c220 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
3 locks held by syz-executor.5/3108:
 #0: ffff88810ea8c438 (sb_writers#4){.+.+}-{0:0}, at: ioctl_setflags fs/ioctl.c:729 [inline]
 #0: ffff88810ea8c438 (sb_writers#4){.+.+}-{0:0}, at: do_vfs_ioctl+0xe36/0x15d0 fs/ioctl.c:843
 #1: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
 #1: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x148/0xb70 fs/ioctl.c:685
 #2: ffff88810ea8ebd0 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ind_migrate+0x237/0x840 fs/ext4/migrate.c:623
1 lock held by syz-executor.5/3109:
 #0: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
 #0: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: process_measurement+0x17c0/0x1920 security/integrity/ima/ima_main.c:241
3 locks held by syz-executor.5/3110:
 #0: ffff88810ea440f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
 #1: ffff88810ea8c438 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0x12d/0x250 fs/read_write.c:647
 #2: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
 #2: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_buffered_write_iter+0xb6/0x500 fs/ext4/file.c:263
1 lock held by syz-executor.5/3111:
 #0: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
 #0: ffff888147b02160 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: process_measurement+0x71a/0x1920 security/integrity/ima/ima_main.c:241

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x49/0x148 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1d5/0x1f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc0f/0xf20 kernel/hung_task.c:295
 kthread+0x3c2/0x4a0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2814 Comm: rs:main Q:Reg Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x7/0x60 kernel/kcov.c:197
Code: ff b9 ff ff ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 44 00 00 65 8b 05 89 36 c0 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 80 ef 01 00 a9
RSP: 0018:ffffc900036e7500 EFLAGS: 00000093
RAX: 0000000080000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888106bcb680 RSI: ffffffff8147cb31 RDI: 0000000000000003
RBP: ffffffff8184e1f1 R08: 0000000000000000 R09: ffff88810ad1288b
R10: ffffffff8147cb28 R11: 0000000000000000 R12: 0000000000000383
R13: ffff88810ad12828 R14: 0000000000000383 R15: ffff88810ad12828
FS:  00007f491ce2e700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4914091108 CR3: 000000010e12a000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 trace_hardirqs_on+0x51/0x1a0 kernel/trace/trace_preemptirq.c:49
 lookup_bh_lru fs/buffer.c:1292 [inline]
 __find_get_block+0x1f1/0xbe0 fs/buffer.c:1304
 __getblk_gfp+0x28/0x80 fs/buffer.c:1330
 sb_getblk include/linux/buffer_head.h:327 [inline]
 __ext4_get_inode_loc+0x36f/0x1120 fs/ext4/inode.c:4336
 ext4_get_inode_loc+0xf3/0x1b0 fs/ext4/inode.c:4454
 ext4_reserve_inode_write+0xca/0x270 fs/ext4/inode.c:5760
 __ext4_mark_inode_dirty+0x17d/0x870 fs/ext4/inode.c:5929
 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5966
 __mark_inode_dirty+0x3fd/0xf70 fs/fs-writeback.c:2398
 mark_inode_dirty include/linux/fs.h:2452 [inline]
 generic_write_end+0x238/0x3f0 fs/buffer.c:2198
 ext4_da_write_end+0x20f/0xb10 fs/ext4/inode.c:3116
 generic_perform_write+0x2c3/0x510 mm/filemap.c:3781
 ext4_buffered_write_iter+0x244/0x500 fs/ext4/file.c:269
 ext4_file_write_iter+0x3bd/0x19b0 fs/ext4/file.c:680
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write+0x40b/0x640 fs/read_write.c:507
 vfs_write+0x77c/0xa90 fs/read_write.c:594
 ksys_write+0x12d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f491f8721cd
Code: c2 20 00 00 75 10 b8 01 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ae fc ff ff 48 89 04 24 b8 01 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 f7 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f491ce2d580 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4914025ee0 RCX: 00007f491f8721cd
RDX: 0000000000001000 RSI: 00007f4914025ee0 RDI: 0000000000000008
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f4914025c60
R13: 00007f491ce2d5a0 R14: 0000000000000007 R15: 0000000000001000
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	b9 ff ff ff ff       	mov    $0xffffffff,%ecx
   5:	ba 08 00 00 00       	mov    $0x8,%edx
   a:	4d 8b 03             	mov    (%r11),%r8
   d:	48 0f bd ca          	bsr    %rdx,%rcx
  11:	49 8b 45 00          	mov    0x0(%r13),%rax
  15:	48 63 c9             	movslq %ecx,%rcx
  18:	e9 64 ff ff ff       	jmpq   0xffffff81
  1d:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  22:	65 8b 05 89 36 c0 7e 	mov    %gs:0x7ec03689(%rip),%eax        # 0x7ec036b2
* 29:	89 c1                	mov    %eax,%ecx <-- trapping instruction
  2b:	48 8b 34 24          	mov    (%rsp),%rsi
  2f:	81 e1 00 01 00 00    	and    $0x100,%ecx
  35:	65 48 8b 14 25 80 ef 	mov    %gs:0x1ef80,%rdx
  3c:	01 00
  3e:	a9                   	.byte 0xa9

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-usb 2021/09/19 10:38 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing ae8709b296d8 70b76c1d .config log report info INFO: task hung in con_flush_chars
* Struck through repros no longer work on HEAD.