All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: commit cfafcd117 "futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()" causes glibc nptl/tst-robustpi8 failure
Date: Thu, 18 May 2017 14:30:54 +0200	[thread overview]
Message-ID: <20170518123054.cp7fqnclvjjgbtyd@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20170518114323.um3znbcoaxo7woo3@hirez.programming.kicks-ass.net>

On Thu, May 18, 2017 at 01:43:23PM +0200, Peter Zijlstra wrote:
> On Thu, May 18, 2017 at 10:34:34AM +0200, Florian Weimer wrote:
> > On 05/18/2017 10:31 AM, Peter Zijlstra wrote:
> 
> > > But it does that after building the tst-robustpi8 thing, so I seem to
> > > have all I need here.
> > 
> > Great, have fun figuring out what's going on. :-/
> 
> 
> 
>  ld-linux-x86-64-2165  [018] ....   290.235869: sched_process_fork: comm=ld-linux-x86-64 pid=2165 child_comm=ld-linux-x86-64 child_pid=2166
>  ld-linux-x86-64-2166  [019] ....   290.436398: handle_futex_death: 00007f066634e870: 876 -> 40000000
>  ld-linux-x86-64-2166  [019] ....   290.436399: handle_futex_death: 00007f066634e0c8: 876 -> 40000000
>  ld-linux-x86-64-2166  [019] ....   290.436400: handle_futex_death: 00007f066634ee38: 80000876 -> c0000000
>  ld-linux-x86-64-2166  [019] ....   290.436401: sched_process_exit: comm=ld-linux-x86-64 pid=2166 prio=120
>  ld-linux-x86-64-2164  [019] ...1   290.436546: attach_to_pi_owner: 2: 00007f066634e078 = 80000876
> 
> 
> 
> 
>  ld-linux-x86-64-2183  [026] ....   827.987914: sched_process_fork: comm=ld-linux-x86-64 pid=2183 child_comm=ld-linux-x86-64 child_pid=2187
>  ld-linux-x86-64-2187  [029] ....   828.188218: handle_futex_death: 00007f76dd361690: 88b -> 40000000
>  ld-linux-x86-64-2187  [029] ....   828.188219: handle_futex_death: 00007f76dd361898: 8000088b -> c0000000
>  ld-linux-x86-64-2187  [029] ....   828.188220: handle_futex_death: 00007f76dd3615c8: 8000088b -> c0000000
>  ld-linux-x86-64-2187  [029] ....   828.188220: handle_futex_death: 00007f76dd3612d0: 8000088b -> c0000000
>  ld-linux-x86-64-2187  [029] ....   828.188220: handle_futex_death: 00007f76dd361af0: 8000088b -> c0000000
>  ld-linux-x86-64-2187  [029] ....   828.188221: handle_futex_death: 00007f76dd361168: 8000088b -> c0000000
>  ld-linux-x86-64-2187  [029] ....   828.188222: sched_process_exit: comm=ld-linux-x86-64 pid=2187 prio=120
>  ld-linux-x86-64-2182  [019] ...1   828.188373: attach_to_pi_owner: 2: 00007f76dd361000 = 8000088b
> 
> 
> 
> In both cases we fail in FUTEX_LOCK_PI trying to acquire a futex owned
> by a dead task, resulting in the -ESRCH.
> 
> Now, pthread_mutex_lock() isn't expecting -ESRCH for robust futexes,
> because for robust we'd expect handle_futex_death() to clear out the
> futex value and set OWNER_DIED, as can be seen above.
> 
> The problem is however that the futex address we fail on, doesn't appear
> to have been fixed up, so its either not on the robust list, or the
> robust list got broken.

The robust list walk finishes without issue. So no premature
terminations. The address really isn't on it.

  reply	other threads:[~2017-05-18 12:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-17 17:36 Markus Trippelsdorf
2017-05-17 17:50 ` Florian Weimer
2017-05-18  6:46   ` Peter Zijlstra
2017-05-18  6:57     ` Peter Zijlstra
2017-05-18  7:40 ` Peter Zijlstra
2017-05-18  8:04   ` Markus Trippelsdorf
2017-05-18  8:14     ` Peter Zijlstra
2017-05-18  8:12   ` Florian Weimer
2017-05-18  8:31     ` Peter Zijlstra
2017-05-18  8:34       ` Florian Weimer
2017-05-18  8:41         ` Peter Zijlstra
2017-05-18  8:42           ` Florian Weimer
2017-05-18 11:43         ` Peter Zijlstra
2017-05-18 12:30           ` Peter Zijlstra [this message]
2017-05-19 15:48         ` Peter Zijlstra
2017-05-19 16:07           ` Peter Zijlstra
2017-05-19 17:35           ` Markus Trippelsdorf
2017-05-22 20:04           ` [tip:locking/urgent] futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock() tip-bot for Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170518123054.cp7fqnclvjjgbtyd@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=fweimer@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=markus@trippelsdorf.de \
    --cc=tglx@linutronix.de \
    --subject='Re: commit cfafcd117 "futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()" causes glibc nptl/tst-robustpi8 failure' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.