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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Anca Emanuel <anca.emanuel@gmail.com>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@elte.hu>, "Tejun Heo" <tj@kernel.org>,
	roland@redhat.com, oleg@redhat.com, jan.kratochvil@redhat.com,
	linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org,
	"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>
Subject: Re: [PATCHSET] ptrace,signal: group stop / ptrace updates
Date: Fri, 28 Jan 2011 13:36:50 -0500	[thread overview]
Message-ID: <20110128183650.GA26633@Krystal> (raw)
In-Reply-To: <AANLkTinm53a1BzLu6JCBdgOpkHw9MOg2H4gD7xiRyvOh@mail.gmail.com>

* Anca Emanuel (anca.emanuel@gmail.com) wrote:
> On Fri, Jan 28, 2011 at 7:41 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > On Fri, 28 Jan 2011, Ingo Molnar wrote:
> >> See that '^C^C' line? That is where i had to do Ctrl-C twice.
> >>
> >> It only fails here about once every 10 times, so it's very rare. I have a stock F14
> >> system running on that box, with the very latest .38 based kernel.
> >
> > Tripped over the refuse ^C thing today twice. Had to kill a kernel
> > build from another shell. It just happily displayed ^C and never
> > stopped. That happens once in a while and I have no idea either how to
> > debug that.
> 
> cc: Mathieu
> 
> Use lttng ?

Heh :) I'm sure Ingo and Thomas have their own tools for that ;) There is
one extra thing in the LTTng instrumentation that can help solve this problem:
the "input subsystem" instrumentation (enabled with ltt-armall -i). You can then
get a dump of:

- Your keystrokes (you can then grep for your ctrl-c input)
- Read/poll/select system calls (so you know when your terminal receives the
  input).
- Signals sent/delivered

Some of these are already instrumented in the mainline kernel, so you might get
away without the input subsystem instrumentation.

If I had to take a wild guess, my bet would be to take a look in the area of
signal delivery, but you never know, maybe it's a userspace bug in the X
terminal emulator code that is causing this weirdness.

Hope this helps,

Mathieu

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2011-01-28 18:36 UTC|newest]

Thread overview: 160+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-28 15:08 [PATCHSET] ptrace,signal: group stop / ptrace updates Tejun Heo
2011-01-28 15:08 ` [PATCH 01/10] signal: fix SIGCONT notification code Tejun Heo
2011-01-28 15:08 ` [PATCH 02/10] ptrace: remove the extra wake_up_process() from ptrace_detach() Tejun Heo
2011-01-28 18:46   ` Roland McGrath
2011-01-31 10:38     ` Tejun Heo
2011-02-01 10:26       ` [PATCH] ptrace: use safer wake up on ptrace_detach() Tejun Heo
2011-02-01 13:40         ` Oleg Nesterov
2011-02-01 15:07           ` Tejun Heo
2011-02-01 19:17             ` Oleg Nesterov
2011-02-02  5:31             ` Roland McGrath
2011-02-02 10:35               ` Tejun Heo
2011-02-02  0:27         ` Andrew Morton
2011-02-02  5:33           ` Roland McGrath
2011-02-02  5:38             ` Andrew Morton
2011-02-02 10:34               ` Tejun Heo
2011-02-02 19:33                 ` Andrew Morton
2011-02-02 20:01                   ` Tejun Heo
2011-02-02 21:40             ` Oleg Nesterov
2011-02-02  5:29         ` Roland McGrath
2011-02-02  5:28       ` [PATCH 02/10] ptrace: remove the extra wake_up_process() from ptrace_detach() Roland McGrath
2011-01-28 15:08 ` [PATCH 03/10] signal: remove superflous try_to_freeze() loop in do_signal_stop() Tejun Heo
2011-01-28 18:46   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 04/10] ptrace: kill tracehook_notify_jctl() Tejun Heo
2011-01-28 21:09   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 05/10] ptrace: add @why to ptrace_stop() Tejun Heo
2011-01-28 18:48   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 06/10] signal: fix premature completion of group stop when interfered by ptrace Tejun Heo
2011-01-28 21:22   ` Roland McGrath
2011-01-31 11:00     ` Tejun Heo
2011-02-02  5:44       ` Roland McGrath
2011-02-02 10:56         ` Tejun Heo
2011-01-28 15:08 ` [PATCH 07/10] signal: use GROUP_STOP_PENDING to stop once for a single group stop Tejun Heo
2011-01-28 15:08 ` [PATCH 08/10] ptrace: participate in group stop from ptrace_stop() iff the task is trapping for " Tejun Heo
2011-01-28 21:30   ` Roland McGrath
2011-01-31 11:26     ` Tejun Heo
2011-02-02  5:57       ` Roland McGrath
2011-02-02 10:53         ` Tejun Heo
2011-02-03 10:02           ` Tejun Heo
2011-02-01 19:36     ` Oleg Nesterov
2011-01-28 15:08 ` [PATCH 09/10] ptrace: make do_signal_stop() use ptrace_stop() if the task is being ptraced Tejun Heo
2011-01-28 15:08 ` [PATCH 10/10] ptrace: clean transitions between TASK_STOPPED and TRACED Tejun Heo
2011-02-03 20:41   ` [PATCH 0/1] (Was: ptrace: clean transitions between TASK_STOPPED and TRACED) Oleg Nesterov
2011-02-03 20:41     ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Oleg Nesterov
2011-02-03 21:36       ` Roland McGrath
2011-02-03 21:44         ` Oleg Nesterov
2011-02-04 10:53           ` Tejun Heo
2011-02-04 13:04             ` Oleg Nesterov
2011-02-04 14:48               ` Tejun Heo
2011-02-04 17:06                 ` Oleg Nesterov
2011-02-05 13:39                   ` Tejun Heo
2011-02-07 13:42                     ` Oleg Nesterov
2011-02-07 14:11                       ` Tejun Heo
2011-02-07 15:37                         ` Oleg Nesterov
2011-02-07 16:31                           ` Tejun Heo
2011-02-07 17:48                             ` Oleg Nesterov
2011-02-09 14:18                               ` Tejun Heo
2011-02-09 14:21                                 ` Tejun Heo
2011-02-09 21:25                                 ` Oleg Nesterov
2011-02-13 23:01                                   ` Denys Vlasenko
2011-02-14  9:03                                     ` Jan Kratochvil
2011-02-14 11:39                                       ` Denys Vlasenko
2011-02-14 17:32                                         ` Oleg Nesterov
2011-02-14 16:01                                       ` Oleg Nesterov
2011-02-26  3:59                                       ` Pavel Machek
2011-02-14 15:51                                     ` Oleg Nesterov
2011-02-14 14:50                                   ` Tejun Heo
2011-02-14 18:53                                     ` Oleg Nesterov
2011-02-13 22:25                                 ` Denys Vlasenko
2011-02-14 15:13                                   ` Tejun Heo
2011-02-14 16:15                                     ` Oleg Nesterov
2011-02-14 16:33                                       ` Tejun Heo
2011-02-14 17:23                                         ` Oleg Nesterov
2011-02-14 17:20                                     ` Denys Vlasenko
2011-02-14 17:30                                       ` Tejun Heo
2011-02-14 17:45                                         ` Oleg Nesterov
2011-02-14 17:54                                         ` Denys Vlasenko
2011-02-21 15:16                                           ` Tejun Heo
2011-02-21 15:28                                             ` Oleg Nesterov
2011-02-21 16:11                                               ` [pseudo patch] ptrace should respect the group stop Oleg Nesterov
2011-02-22 16:24                                               ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Tejun Heo
2011-02-24 21:08                                                 ` Oleg Nesterov
2011-02-25 15:45                                                   ` Tejun Heo
2011-02-25 17:42                                                     ` Roland McGrath
2011-02-28 15:23                                                     ` Oleg Nesterov
2011-02-14 17:51                                       ` Oleg Nesterov
2011-02-14 18:55                                         ` Denys Vlasenko
2011-02-14 19:01                                           ` Oleg Nesterov
2011-02-14 19:42                                             ` Denys Vlasenko
2011-02-14 20:01                                               ` Oleg Nesterov
2011-02-15 15:24                                                 ` Tejun Heo
2011-02-15 15:58                                                   ` Oleg Nesterov
2011-02-15 17:31                                                   ` Roland McGrath
2011-02-15 20:27                                                     ` Oleg Nesterov
2011-02-18 17:02                                                       ` Tejun Heo
2011-02-18 19:37                                                         ` Oleg Nesterov
2011-02-21 16:22                                                           ` Tejun Heo
2011-02-21 16:49                                                             ` Oleg Nesterov
2011-02-21 16:59                                                               ` Tejun Heo
2011-02-23 19:31                                                                 ` Oleg Nesterov
2011-02-25 15:10                                                                   ` Tejun Heo
2011-02-24 20:29                                                             ` Oleg Nesterov
2011-02-25 15:51                                                               ` Tejun Heo
2011-02-26  2:48                                                                 ` Denys Vlasenko
2011-02-28 12:56                                                                   ` Tejun Heo
2011-02-28 13:16                                                                     ` Denys Vlasenko
2011-02-28 13:29                                                                       ` Tejun Heo
2011-02-28 13:41                                                                         ` Denys Vlasenko
2011-02-28 13:53                                                                           ` Tejun Heo
2011-02-28 14:25                                                                             ` Denys Vlasenko
2011-02-28 14:39                                                                               ` Tejun Heo
2011-02-28 16:48                                                                                 ` Oleg Nesterov
2011-02-28 14:36                                                                   ` Oleg Nesterov
2011-02-16 21:51                                       ` Jan Kratochvil
2011-02-17  3:37                                         ` Denys Vlasenko
2011-02-17 19:19                                           ` Oleg Nesterov
2011-02-18 21:11                                             ` Jan Kratochvil
2011-02-19 20:16                                               ` Oleg Nesterov
2011-02-17 16:49                                         ` Oleg Nesterov
2011-02-17 18:58                                           ` Roland McGrath
2011-02-17 19:33                                             ` Oleg Nesterov
2011-02-18 21:34                                           ` Jan Kratochvil
2011-02-19 20:06                                             ` Oleg Nesterov
2011-02-20  9:40                                               ` Jan Kratochvil
2011-02-20 17:06                                                 ` Denys Vlasenko
2011-02-20 17:48                                                   ` Oleg Nesterov
2011-02-20 19:10                                                   ` Jan Kratochvil
2011-02-20 19:16                                                     ` Oleg Nesterov
2011-02-20 17:16                                                 ` Oleg Nesterov
2011-02-20 18:52                                                   ` Jan Kratochvil
2011-02-20 20:38                                                     ` Oleg Nesterov
2011-02-20 21:06                                                       ` `(T) stopped' preservation after _exit() [Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH] Jan Kratochvil
2011-02-20 21:19                                                         ` Oleg Nesterov
2011-02-20 21:20                                                       ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Jan Kratochvil
2011-02-21 14:23                                                         ` Oleg Nesterov
2011-02-23 16:44                                                           ` Jan Kratochvil
2011-02-14 15:31                                   ` Oleg Nesterov
2011-02-14 17:24                                     ` Denys Vlasenko
2011-02-14 17:39                                       ` Oleg Nesterov
2011-02-14 17:57                                         ` Denys Vlasenko
2011-02-14 18:00                                           ` Oleg Nesterov
2011-02-14 18:06                                             ` Oleg Nesterov
2011-02-14 18:59                                         ` Denys Vlasenko
2011-02-13 21:24                 ` Denys Vlasenko
2011-02-14 15:06                   ` Oleg Nesterov
2011-02-14 15:19                     ` Tejun Heo
2011-02-14 16:20                       ` Oleg Nesterov
2011-02-14 17:05                     ` Denys Vlasenko
2011-02-14 17:18                       ` Oleg Nesterov
2011-01-28 16:54 ` [PATCHSET] ptrace,signal: group stop / ptrace updates Ingo Molnar
2011-01-28 17:41   ` Thomas Gleixner
2011-01-28 18:04     ` Anca Emanuel
2011-01-28 18:36       ` Mathieu Desnoyers [this message]
2011-01-28 17:55   ` Oleg Nesterov
2011-01-28 18:29     ` Bash not reacting to Ctrl-C Ingo Molnar
2011-02-05 20:34       ` Oleg Nesterov
2011-02-07 13:08         ` Oleg Nesterov
2011-02-09  6:17           ` Michael Witten
2011-02-09 14:53             ` Ingo Molnar
2011-02-09 19:37               ` Michael Witten
2011-02-11 14:41           ` Pavel Machek

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