syzbot


INFO: task hung in tty_release

Status: auto-closed as invalid on 2020/06/26 02:50
Reported-by: syzbot+07174b5174cb387a8d5a@syzkaller.appspotmail.com
First crash: 861d, last: 861d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in tty_release 2 1452d 1453d 0/22 auto-closed as invalid on 2019/02/22 10:22
android-49 INFO: task hung in tty_release 21 946d 1180d 0/3 auto-closed as invalid on 2020/04/02 02:37

Sample crash report:
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=1549 sclass=netlink_route_socket pig=23881 comm=syz-executor.0
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=1549 sclass=netlink_route_socket pig=23883 comm=syz-executor.0
INFO: task syz-executor.4:8318 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8318   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8347 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8347   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8368 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8368   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8391 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8391   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8411 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8411   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8438 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8438   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8468 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8468   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8486 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8486   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8502 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8502   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c
INFO: task syz-executor.4:8526 blocked for more than 140 seconds.
      Not tainted 4.14.171-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28608  8526   7330 0x80000002
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9f2/0x2b00 kernel/exit.c:858
 do_group_exit+0x100/0x310 kernel/exit.c:955
 get_signal+0x385/0x1ca0 kernel/signal.c:2418
 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007f0faf837cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf28 RCX: 000000000045c449
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf28
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf2c
R13: 00007ffd31b6c27f R14: 00007f0faf8389c0 R15: 000000000076bf2c

Showing all locks held in the system:
1 lock held by khungtaskd/1057:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81465b53>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
2 locks held by getty/7283:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7284:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7285:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7286:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7287:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7288:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339ca44>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/8318:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8347:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8368:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8391:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8411:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8438:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8468:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8486:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8502:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8526:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8561:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8582:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8609:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8632:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8655:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8679:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8710:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8734:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8757:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8783:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/8823:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/22276:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/22300:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22381:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22394:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22403:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.2/22432:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/22434:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.2/22451:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.4/22452:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22498:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22509:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
1 lock held by syz-executor.0/22528:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
2 locks held by syz-executor.4/23826:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&buf->lock){+.+.}, at: [<ffffffff833cc6b7>] paste_selection+0x107/0x3ca drivers/tty/vt/selection.c:349
2 locks held by getty/23864:
 #0:  (&tty->legacy_mutex){+.+.}, at: [<ffffffff833aea2f>] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19
 #1:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a98ad>] __tty_ldisc_lock drivers/tty/tty_ldisc.c:332 [inline]
 #1:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a98ad>] tty_ldisc_lock+0x4d/0x80 drivers/tty/tty_ldisc.c:356
2 locks held by syz-executor.0/23881:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&buf->lock){+.+.}, at: [<ffffffff833cc6b7>] paste_selection+0x107/0x3ca drivers/tty/vt/selection.c:349
2 locks held by syz-executor.2/23882:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&buf->lock){+.+.}, at: [<ffffffff833cc6b7>] paste_selection+0x107/0x3ca drivers/tty/vt/selection.c:349
2 locks held by syz-executor.2/23889:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833a8e02>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&buf->lock){+.+.}, at: [<ffffffff833cc6b7>] paste_selection+0x107/0x3ca drivers/tty/vt/selection.c:349

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

NMI backtrace for cpu 1
CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 4.14.171-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+0x13e/0x194 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x139/0x17e 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+0x5e2/0xb80 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: 23878 Comm: syz-executor.0 Not tainted 4.14.171-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888050cfc640 task.stack: ffff8880585a8000
RIP: 0010:mark_held_locks+0x8e/0xf0 kernel/locking/lockdep.c:2842
RSP: 0018:ffff8880585af8d0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff1100a19f9e1
RDX: 0000000000000002 RSI: ffff888050cfcec0 RDI: ffff888050cfcee2
RBP: 0000000000000007 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000006
R13: ffff888050cfc640 R14: dffffc0000000000 R15: ffff888050cfcec0
FS:  00007fc84547e700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c4436d9000 CR3: 00000000a7c0b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2879 [inline]
 trace_hardirqs_on_caller+0x3f6/0x590 kernel/locking/lockdep.c:2926
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x24/0x80 kernel/locking/spinlock.c:200
 rq_unlock_irq kernel/sched/sched.h:1766 [inline]
 __schedule+0x135d/0x1ca0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 paste_selection+0x27e/0x3ca drivers/tty/vt/selection.c:355
 tioclinux+0x107/0x410 drivers/tty/vt/vt.c:2696
 vt_ioctl+0x169a/0x2010 drivers/tty/vt/vt_ioctl.c:364
 tty_ioctl+0x6c5/0x1220 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c449
RSP: 002b:00007fc84547dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc84547e6d4 RCX: 000000000045c449
RDX: 0000000020000040 RSI: 000000000000541c RDI: 0000000000000008
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000571 R14: 00000000004c7c29 R15: 000000000076bf2c
Code: 00 00 48 63 c3 48 8d 04 80 49 8d 34 c7 48 8d 7e 22 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 42 0f b6 04 30 38 d0 7f 04 84 c0 75 4c <0f> b6 46 22 44 89 e2 a8 03 0f 45 d5 a8 04 74 0c 4c 89 ef e8 aa 

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/02/27 02:49 linux-4.14.y 98db2bf27b9e 251aabb7 .config log report