Re: [Bug #10815] 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0

From: Alexey Dobriyan
Date: Sat Jun 14 2008 - 15:48:22 EST


On Sat, Jun 14, 2008 at 11:12:12AM -0700, Paul E. McKenney wrote:
> On Sat, Jun 14, 2008 at 06:58:39PM +0400, Oleg Nesterov wrote:
> > On 06/14, Paul E. McKenney wrote:
> > >
> > > On Fri, Jun 13, 2008 at 04:52:55PM +0300, Adrian Bunk wrote:
> > > > On Sat, Jun 07, 2008 at 10:42:57PM +0200, Rafael J. Wysocki wrote:
> > > > > This message has been generated automatically as a part of a report
> > > > > of recent regressions.
> > > > >
> > > > > The following bug entry is on the current list of known regressions
> > > > > from 2.6.25. Please verify if it still should be listed.
> > > > >
> > > > >
> > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=10815
> > > > > Subject : 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0
> > > > > Submitter : Alexey Dobriyan <adobriyan@xxxxxxxxx>
> > > > > Date : 2008-05-27 09:23 (12 days old)
> > > > > References : http://lkml.org/lkml/2008/5/27/9
> > > > > Handled-By : Oleg Nesterov <oleg@xxxxxxxxxx>
> > > > > Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > > > > Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > > > > Patch : http://lkml.org/lkml/2008/5/28/16
> > > >
> > > > What happened with this issue?
> > >
> > > The patch listed above works for me, passes rcutorture, &c. However,
> > > I never have been able to reproduce the original problem, so cannot say
> > > whether it qualifies as a fix.
> >
> > I doubt very much RCU was the reason of this problem.
>
> Although I very much appreciate your confidence in my code, it is new
> code, so therefore under suspicion.
>
> > Alexey, how did you trigger this problem?
>
> One of them involved running LTP while doing 170 kernel builds in
> parallel.

My gut feeling is that find_pid_ns oops, __d_lookup oops and
__call_for_each_cic oops are the same bug.

And rcutorture failures I've mentioned to Paul privately.

Oleg, debugging you've posted never triggered.

kerneloops suggests that I'm alone. :-(

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