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

[Andrei Vagin]

On Fri, Mar 31, 2017 at 03:19:48PM +0200, Greg Kroah-Hartman wrote:
> On Wed, Mar 15, 2017 at 10:57:14PM -0700, Andrei Vagin wrote:
> > 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
> 
> Any chance to narrow this down to a commit with 'git bisect'?

We run CRIU tests once a day and have seen this issue only once. I don't
have a reproducer for this issue.

Thanks,
Andrei

> 
> thanks,
> 
> greg k-h