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From: Dave Jones <davej@redhat.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Motohiro Kosaki <Motohiro.Kosaki@us.fujitsu.com>,
	Sasha Levin <sasha.levin@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Bob Liu <lliubbo@gmail.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"walken@google.com" <walken@google.com>,
	Motohiro Kosaki JP <kosaki.motohiro@jp.fujitsu.com>,
	"riel@redhat.com" <riel@redhat.com>,
	"stable@kernel.org" <stable@kernel.org>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Bob Liu <bob.liu@oracle.com>
Subject: Re: [PATCH] mm: remove BUG_ON() from mlock_vma_page()
Date: Tue, 11 Mar 2014 14:43:53 -0400	[thread overview]
Message-ID: <20140311184353.GA10764@redhat.com> (raw)
In-Reply-To: <5314A9E9.6090802@suse.cz>

On Mon, Mar 03, 2014 at 05:12:25PM +0100, Vlastimil Babka wrote:

 > >> On 01/31/2014 03:33 PM, Andrew Morton wrote:
 > >>> On Wed, 18 Dec 2013 08:42:49 +0800 Bob Liu<lliubbo@gmail.com>  wrote:
 > >>>
 > >>>>> This BUG_ON() was triggered when called from try_to_unmap_cluster()
 > >>>>> which didn't lock the page.
 > >>>>> And it's safe to mlock_vma_page() without PageLocked, so this patch
 > >>>>> fix this issue by removing that BUG_ON() simply.
 > >>>>>
 > >>> This patch doesn't appear to be going anywhere, so I will drop it.
 > >>> Please let's check to see whether the bug still exists and if so,
 > >>> start another round of bugfixing.
 > >>
 > >> This bug still happens on the latest -next kernel.
 > >
 > > Yeah, I recognized it. I'm preparing new patch. Thanks.
 > 
 > What will be your approach? After we had the discussion some month ago 
 > about m(un)lock vs migration I've concluded that there is no race that 
 > page lock helps, and removing the BUG_ON() would be indeed correct. Just 
 > needs to be correctly explained and documentation updated as well.

This is not just a -next problem btw, I just hit this in 3.14-rc6

	Dave

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  reply	other threads:[~2014-03-11 19:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-18  0:42 [PATCH] mm: remove BUG_ON() from mlock_vma_page() Bob Liu
2013-12-18  9:36 ` Vlastimil Babka
2013-12-18 10:26   ` Bob Liu
2013-12-18 19:31 ` Motohiro Kosaki
2013-12-18 22:30 ` Andrew Morton
2014-01-31 20:33 ` Andrew Morton
2014-02-23 19:32   ` Sasha Levin
2014-02-24 17:57     ` Motohiro Kosaki
2014-03-03 16:12       ` Vlastimil Babka
2014-03-11 18:43         ` Dave Jones [this message]
2014-03-20  9:18           ` Bob Liu
2014-03-20 10:36             ` Vlastimil Babka

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