Re: bad rss-counter message in 3.14rc5

[Sasha Levin <sasha.levin@oracle.com>]

On 03/11/2014 01:30 AM, Dave Jones wrote:
> On Mon, Mar 10, 2014 at 10:01:58PM -0700, Andrew Morton wrote:
>   > On Tue, 11 Mar 2014 00:51:09 -0400 Dave Jones <davej@redhat.com> wrote:
>   >
>   > > On Mon, Mar 10, 2014 at 09:46:12PM -0700, Andrew Morton wrote:
>   > >  > On Mon, 10 Mar 2014 20:13:40 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
>   > >  >
>   > >  > > > Anyone ? I'm hitting this trace on an almost daily basis, which is a pain
>   > >  > > > while trying to reproduce a different bug..
>   > >  > >
>   > >  > > Damn, I thought we'd fixed that but it seems not.  Cc's added.
>   > >  > >
>   > >  > > Guys, what stops the migration target page from coming unlocked in
>   > >  > > parallel with zap_pte_range()'s call to migration_entry_to_page()?
>   > >  >
>   > >  > page_table_lock, sort-of.  At least, transitions of is_migration_entry()
>   > >  > and page_locked() happen under ptl.
>   > >  >
>   > >  > I don't see any holes in regular migration.  Do you know if this is
>   > >  > reproducible with CONFIG_NUMA_BALANCING=n or CONFIG_NUMA=n?
>   > >
>   > > CONFIG_NUMA_BALANCING was n already btw, so I'll do a NUMA=n run.
>   >
>   > There probably isn't much point unless trinity is using
>   > sys_move_pages().  Is it?  If so it would be interesting to disable
>   > trinity's move_pages calls and see if it still fails.
>
> Ok, with move_pages excluded it still oopses.

FWIW, yes - I still see both of these issues happening. It's easy to ignore the
bad rss-counter, and I've commented out the BUG at swapops.h so that I could keep
on testing.

There are quite a few issues within mm/ right now, I think there are more than 5
different BUG()s hittable using trinity at this point without a fix.


Thanks,
Sasha

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