Messages in this thread | | | Date | Fri, 28 Jan 2011 13:36:50 -0500 | From | Mathieu Desnoyers <> | Subject | Re: [PATCHSET] ptrace,signal: group stop / ptrace updates |
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* 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
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