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From: Andrew Morton <akpm@linux-foundation.org>
To: Sami Liedes <sami.liedes@iki.fi>
Cc: linux-mm@kvack.org, bugzilla-daemon@bugzilla.kernel.org
Subject: Re: [Bug 43227] New: BUG: Bad page state in process wcg_gfam_6.11_i
Date: Fri, 11 May 2012 13:32:34 -0700	[thread overview]
Message-ID: <20120511133234.6130b69a.akpm@linux-foundation.org> (raw)
In-Reply-To: <20120511200213.GB7387@sli.dy.fi>

On Fri, 11 May 2012 23:02:13 +0300
Sami Liedes <sami.liedes@iki.fi> wrote:

> On Fri, May 11, 2012 at 12:59:21PM -0700, Andrew Morton wrote:
> > > [67031.755786] BUG: Bad page state in process wcg_gfam_6.11_i  pfn:02519
> > > [67031.755790] page:ffffea0000094640 count:0 mapcount:0 mapping:         
> > > (null) index:0x7f1eb293b
> > > [67031.755792] page flags: 0x4000000000000014(referenced|dirty)
> > 
> > AFAICT we got this warning because the page allocator found a free page
> > with PG_referenced and PG_dirty set.
> > 
> > It would be a heck of a lot more useful if we'd been told about this
> > when the page was freed, not when it was reused!  Can anyone think of a
> > reason why PAGE_FLAGS_CHECK_AT_FREE doesn't include these flags (at
> > least)?
> 
> Would it be useful if I tried to reproduce this with some debugging
> options turned on, for example CONFIG_DEBUG_VM?
> 

Sure, thanks, that might turn something up. 
Documentation/SubmitChecklist recommends 

: 12: Has been tested with CONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT,
:     CONFIG_DEBUG_SLAB, CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES,
:     CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_ATOMIC_SLEEP, CONFIG_PROVE_RCU
:     and CONFIG_DEBUG_OBJECTS_RCU_HEAD all simultaneously enabled.

although that list might be a bit out of date; it certainly should
include CONFIG_DEBUG_VM!

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  reply	other threads:[~2012-05-11 20:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-43227-27@https.bugzilla.kernel.org/>
2012-05-11 19:59 ` [Bug 43227] New: BUG: Bad page state in process wcg_gfam_6.11_i Andrew Morton
2012-05-11 20:02   ` Sami Liedes
2012-05-11 20:32     ` Andrew Morton [this message]
2012-05-11 20:59       ` Dave Jones
2012-05-11 22:23       ` Sami Liedes
2012-05-14  0:25         ` Dave Jones
2012-05-11 20:06   ` Dave Jones
2012-05-11 20:10     ` Andrew Morton
2012-05-11 22:14       ` Sami Liedes
2012-05-11 21:30   ` Hugh Dickins
2012-05-11 22:56     ` Sami Liedes
2012-05-14  0:30     ` Dave Jones

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