Re: utrace regressions (was: -mm merge plans for 2.6.21)

From: Alexey Dobriyan
Date: Thu Feb 15 2007 - 07:02:38 EST


On Tue, Feb 13, 2007 at 04:05:30PM +0300, Alexey Dobriyan wrote:
> On Mon, Feb 12, 2007 at 01:36:34PM -0800, Roland McGrath wrote:
> > > 2. The following proggie renders box unusable in ~10 seconds (but not
> > > mainline kernel where Ctrl+C will kill process).
> >
> > I haven't been able to reproduce this so far on my test machine. I got
> > bored after about 10 minutes ("passed: 119200000"). The machine remains
> > responsive and the test dies immediately on hitting C-c. I'll try it on
> > some other machines. It would help to know what kind of unusable (crashy,
> > leaky, wedgey?).
>
> This is fresh pull 2.6.20-ec2f9d1331f658433411c58077871e1eef4ee1b4 with
> linux-2.6.20-current-utrace.patch slapped on top (without rejects)
> utrace is on and ptrace is on too.
>
> the behaviour is
>
> $ expl_ptratt
> passed: 100000
> passed: 200000
> ...
> passed: [always different number, but in several seconds]
> [pause]
> [OOM killer wakes up steadily killing processes ]
> [messages scroll away ]
>
> I'll turn more debugging options now.
>
> Just in case, .config:

Turning preempt off makes OOM-killings dissapear.

> # CONFIG_PREEMPT_NONE is not set
> CONFIG_PREEMPT_VOLUNTARY=y
> # CONFIG_PREEMPT is not set
> # CONFIG_X86_UP_APIC is not set

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