Re: 2.6.21-rc2-mm2 hang

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 07 Mar 2007 15:07:21 -0800
Dave Hansen <hansendc@us.ibm.com> wrote:

> On Wed, 2007-03-07 at 14:16 -0800, Siddha, Suresh B wrote:
> > On Wed, Mar 07, 2007 at 02:12:16PM -0800, Dave Hansen wrote:
> > > I'm seeing weird hangs running ltp on 2.6.21-rc2-mm2.  It manifests
> > > itself by the waitpid06 test in LTP hanging.  This is very, very
> > > reproducible in about 5 seconds by adding '-s wait' to the ltp command
> > > line.
> > > 
> > > I see 4 waitpid06 processes on my 4-way machine spinning in userspace.
> > > But, the weird part is that I can't ssh in once this happens, but I can
> > > log in to the console.  I've bisected it down to:
> > >         
> > >         sched-fix-idle-load-balancing-in-softirqd-context
> > 
> > This sounds like an issue in merge we recently had and 2.6.21-rc2-mm2 already
> > has a fix for this.
> > 
> > sched-fix-idle-load-balancing-in-softirqd-context-fix.patch  
> > 
> > Can you please apply both
> > sched-fix-idle-load-balancing-in-softirqd-context
> > sched-fix-idle-load-balancing-in-softirqd-context-fix.patch
> > and see if you still see this problem?
> 
> I was confused that I couldn't find this fix in my patches directory,
> but I double-checked, and realized that I was still on 2.6.21-rc2-mm1.
> I must have grabbed the wrong broken-out tarball when I started the
> bisect.  Darn.
> 
> Anyway, 2.6.21-rc2-mm2 appears to be OK.  Sorry for the false alarm.
> 

Ah, OK.  I'll undrop those three patches.

Michal, did rc2-mm2 make that weird hang go away for you?