JVM stuck/looping in futex call

[Sundara Mohan M]

HI David,
    Did you mean to get stack trace of that process? I could attach to gdb
but not sure where to keep breakpoint.
More info on how to get this will be helpful.


Thanks
Sundar

On Fri, Nov 1, 2019 at 4:03 PM David Holmes <david.holmes at oracle.com> wrote:

> Hi Sundar,
>
> On 2/11/2019 5:39 am, Sundara Mohan M wrote:
> > Hi,
> >      I am running openjdk12/Linux on our systems and see jvm not
> responding
> > to jstack or any diagnostic command (jcmd VM.info/Thread.print). Though
> > application is running fine.
>
> That would sound like the attach thread (which would respond to the
> jstack or other diagnostic command) is in some kind of bad state.
>
> > I see following stack track
> >
> > Process 115586 attached
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL) = ? ERESTARTSYS (To be
> > restarted if SA_RESTART is set)
> > --- SIGQUIT {si_signo=SIGQUIT, si_code=SI_USER, si_pid=115587,
> si_uid=1000}
> > ---
> > futex(0x7feee8008bf8, FUTEX_WAKE_PRIVATE, 1) = 1
> > rt_sigreturn()                          = 202
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL) = ? ERESTARTSYS (To be
> > restarted if SA_RESTART is set)
> > --- SIGQUIT {si_signo=SIGQUIT, si_code=SI_USER, si_pid=115587,
> si_uid=1000}
> > ---
> > futex(0x7feee8008bf8, FUTEX_WAKE_PRIVATE, 1) = 1
> > rt_sigreturn()                          = 202
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL) = ? ERESTARTSYS (To be
> > restarted if SA_RESTART is set)
> > --- SIGQUIT {si_signo=SIGQUIT, si_code=SI_USER, si_pid=115587,
> si_uid=1000}
> > ---
> > futex(0x7feee8008bf8, FUTEX_WAKE_PRIVATE, 1) = 1
> > rt_sigreturn()                          = 202
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL) = ? ERESTARTSYS (To be
> > restarted if SA_RESTART is set)
> > --- SIGQUIT {si_signo=SIGQUIT, si_code=SI_USER, si_pid=115587,
> si_uid=1000}
> > ---
> > rt_sigreturn()                          = 202
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL) = ? ERESTARTSYS (To be
> > restarted if SA_RESTART is set)
> > --- SIGQUIT {si_signo=SIGQUIT, si_code=SI_USER, si_pid=115587,
> si_uid=1000}
> > ---
> > rt_sigreturn()                          = 202
> > futex(0x7feeeffa19d0, FUTEX_WAIT, 116198, NULL^CProcess 115586 detached
> >   <detached ...>
> >
> > Can someone help me understand what is happening here?
>
> It appears that in responding to the SIGQUIT that is used to trigger the
> starting of the attach listener thread, that something is going wrong.
> We appear to be continually restarting an operation that still sees the
> signal pending - which doesn't really make sense to me. Can you get a
> complete stack trace using gdb?
>
> > Please redirect me to proper ilist if this is not correct list for these
> > type of questions.
>
> This list is fine. It may end up being an issue for serviceability-dev
> but we can deal with that later. :)
>
> Thanks,
> David
> -----
>
> >
> > TIA
> > Sundar
> >
>