linux-next: tty: BUG: spinlock bad magic on CPU#0, init/1

[Andrei Vagin]

Hello,

We run CRIU tests for linux-next and here is a new bug in the kernel log

[    2.431229] Freeing unused kernel memory: 1356K
[    2.436371] Freeing unused kernel memory: 168K
[    2.522236] BUG: spinlock bad magic on CPU#0, init/1
[    2.527487]  lock: 0xffff94915477fd88, .magic: 00000000, .owner:
<none>/-1, .owner_cpu: -1
[    2.537257] CPU: 0 PID: 1 Comm: init Not tainted 4.11.0-rc1-next-20170310 #1
[    2.541136] Hardware name: Google Google Compute Engine/Google
Compute Engine, BIOS Google 01/01/2011
[    2.541136] Call Trace:
[    2.541136]  dump_stack+0x85/0xc9
[    2.541136]  spin_bug+0xa6/0xad
[    2.541136]  do_raw_spin_lock+0x66/0xa0
[    2.541136]  _raw_spin_lock+0x40/0x50
[    2.541136]  ? check_tty_count+0x27/0xe0
[    2.541136]  check_tty_count+0x27/0xe0
[    2.541136]  tty_release+0x64/0x620
[    2.541136]  __fput+0xfa/0x230
[    2.541136]  ____fput+0xe/0x10
[    2.541136]  task_work_run+0x83/0xc0
[    2.541136]  exit_to_usermode_loop+0x64/0x9a
[    2.541136]  syscall_return_slowpath+0xa9/0xe0
[    2.541136]  entry_SYSCALL_64_fastpath+0xc0/0xc2
[    2.541136] RIP: 0033:0x7fb953f58e10
[    2.541136] RSP: 002b:00007fff3d276ba8 EFLAGS: 00000246 ORIG_RAX:
0000000000000003
[    2.541136] RAX: 0000000000000000 RBX: 00005610f1867710 RCX: 00007fb953f58e10
[    2.541136] RDX: fffffffffffffe80 RSI: 0000000000000001 RDI: 0000000000000002
[    2.541136] RBP: 0000000000000000 R08: 00005610f165786e R09: 00005610f21bef90
[    2.541136] R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000001
[    2.541136] R13: 00005610f1867674 R14: 00005610f1867678 R15: 0000000000000001
[    2.748104] tsc: Refined TSC clocksource calibration: 2299.999 MHz

All logs are here:
https://s3.amazonaws.com/archive.travis-ci.org/jobs/211615735/log.txt

Thanks,
Andrei