From: Andrew Morton <akpm@osdl.org>
To: Badari Pulavarty <pbadari@us.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.6.9-rc2-mm4 ps hang ?
Date: Fri, 1 Oct 2004 17:44:00 -0700 [thread overview]
Message-ID: <20041001174400.2482186a.akpm@osdl.org> (raw)
In-Reply-To: <1096676374.12861.91.camel@dyn318077bld.beaverton.ibm.com>
Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
>
> On Fri, 2004-10-01 at 16:49, Andrew Morton wrote:
> > Badari Pulavarty <pbadari@us.ibm.com> wrote:
> > >
> > > Here is the full sysrq-t output.
> >
> > What's this guy up to?
> ...
> >
> > Something is seriously screwed up if it's stuck in try_to_wake_up(). Tried
> > generating a few extra traces?
> >
> > Then again, maybe we're missing an up_read() somewhere. hrm, I'll check.
> >
>
> It reproduced again. I think this is the one causing all the troubles..
>
> db2fmcd D ffffffff80132e2a 0 10854 7636
> (NOTLB)
> 00000101bae85ef8 0000000000000002 0000020800000018 00000101d9ddd550
> 0000000100000084 000001016d490e20 000001016d491158
> 00000101d9ddd550
> 0000000000000206 ffffffff801353cb
> Call Trace:<ffffffff801353cb>{try_to_wake_up+971}
> <ffffffff804455f0>{__down_write+128}
> <ffffffff80125e6f>{sys32_mmap+143}
> <ffffffff80124af1>{ia32_sysret+0}
>
> when I tried looking at /proc/10854 - it hung.
OK, so maybe that CPU is spinning in try_to_wake_up(). Can you tell if one
CPU is busy when this happens?
Or you could try Peter's suggestion:
--- 25/kernel/sched.c~a 2004-10-01 17:43:32.500700488 -0700
+++ 25-akpm/kernel/sched.c 2004-10-01 17:43:34.754357880 -0700
@@ -1606,7 +1606,7 @@ out_set_cpu:
task_rq_unlock(rql, &flags);
/* might preempt at this point */
rql = task_rq_lock(p, &flags);
- adjust_sched_timestamp(p, old_rq);
+// adjust_sched_timestamp(p, old_rq);
old_state = p->state;
if (!(old_state & state))
goto out;
_
next prev parent reply other threads:[~2004-10-02 0:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-01 16:08 2.6.9-rc2-mm4 ps hang ? Badari Pulavarty
2004-10-01 19:09 ` Andrew Morton
2004-10-01 20:06 ` Hugh Dickins
2004-10-01 20:59 ` Andrew Morton
2004-10-01 21:29 ` Badari Pulavarty
2004-10-01 21:55 ` Andrew Morton
2004-10-01 23:06 ` Badari Pulavarty
2004-10-01 23:49 ` Andrew Morton
2004-10-02 0:13 ` Peter Williams
2004-10-02 0:19 ` Badari Pulavarty
2004-10-02 0:44 ` Andrew Morton [this message]
2004-10-04 15:43 ` Badari Pulavarty
2004-10-02 0:29 ` Badari Pulavarty
2004-10-02 0:42 ` Andrew Morton
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