From: Dave Hansen <dave.hansen@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Hugh Dickins <hughd@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Tony Luck <tony.luck@intel.com>
Subject: Re: Dirty/Access bits vs. page content
Date: Tue, 22 Apr 2014 14:46:39 -0700 [thread overview]
Message-ID: <5356E33F.3000908@intel.com> (raw)
In-Reply-To: <CA+55aFzM+NpE-EzJdDeYX=cqWRzkGv9o-vybDR=oFtDLMRK-mA@mail.gmail.com>
On 04/22/2014 02:36 PM, Linus Torvalds wrote:
> That said, Dave Hansen did report a BUG_ON() in
> mpage_prepare_extent_to_map(). His line number was odd, but I assume
> it's this one:
>
> BUG_ON(PageWriteback(page));
>
> which may be indicative of some oddity here wrt the dirty bit.
I just triggered it a second time. It only happens with my debugging
config[1] *and* those two fix patches. It doesn't happen on the vanilla
kernel with lost dirty bit.
The line numbers point to the
head = page_buffers(page);
which is:
#define page_buffers(page) \
({ \
BUG_ON(!PagePrivate(page)); \
((struct buffer_head *)page_private(page)); \
})
1.
http://sr71.net/~dave/intel/20140422-lostdirtybit/config-ext4-bugon.20140422
Config that doesn't trigger it:
http://sr71.net/~dave/intel/20140422-lostdirtybit/config-ext4-nobug.20140422
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next prev parent reply other threads:[~2014-04-22 21:46 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1398032742.19682.11.camel@pasglop>
[not found] ` <CA+55aFz1sK+PF96LYYZY7OB7PBpxZu-uNLWLvPiRz-tJsBqX3w@mail.gmail.com>
[not found] ` <1398054064.19682.32.camel@pasglop>
[not found] ` <1398057630.19682.38.camel@pasglop>
[not found] ` <CA+55aFwWHBtihC3w9E4+j4pz+6w7iTnYhTf4N3ie15BM9thxLQ@mail.gmail.com>
[not found] ` <53558507.9050703@zytor.com>
[not found] ` <CA+55aFxGm6J6N=4L7exLUFMr1_siNGHpK=wApd9GPCH1=63PPA@mail.gmail.com>
[not found] ` <53559F48.8040808@intel.com>
2014-04-22 0:31 ` Dirty/Access bits vs. page content Linus Torvalds
2014-04-22 0:44 ` Linus Torvalds
2014-04-22 5:15 ` Tony Luck
2014-04-22 14:55 ` Linus Torvalds
2014-04-22 7:34 ` Peter Zijlstra
2014-04-22 7:54 ` Peter Zijlstra
2014-04-22 21:36 ` Linus Torvalds
2014-04-22 21:46 ` Dave Hansen [this message]
2014-04-22 22:08 ` Linus Torvalds
2014-04-22 22:41 ` Dave Hansen
2014-04-23 2:44 ` Linus Torvalds
2014-04-23 3:08 ` Hugh Dickins
2014-04-23 4:23 ` Linus Torvalds
2014-04-23 6:14 ` Benjamin Herrenschmidt
2014-04-23 18:41 ` Jan Kara
2014-04-23 19:33 ` Linus Torvalds
2014-04-24 6:51 ` Peter Zijlstra
2014-04-24 18:40 ` Hugh Dickins
2014-04-24 19:45 ` Linus Torvalds
2014-04-24 20:02 ` Hugh Dickins
2014-04-24 23:46 ` Linus Torvalds
2014-04-25 1:37 ` Benjamin Herrenschmidt
2014-04-25 2:41 ` Benjamin Herrenschmidt
2014-04-25 2:46 ` Linus Torvalds
2014-04-25 2:50 ` H. Peter Anvin
2014-04-25 3:03 ` Linus Torvalds
2014-04-25 12:01 ` Hugh Dickins
2014-04-25 13:51 ` Peter Zijlstra
2014-04-25 19:41 ` Hugh Dickins
2014-04-26 18:07 ` Peter Zijlstra
2014-04-27 7:20 ` Peter Zijlstra
2014-04-27 12:20 ` Hugh Dickins
2014-04-27 19:33 ` Peter Zijlstra
2014-04-27 19:47 ` Linus Torvalds
2014-04-27 20:09 ` Hugh Dickins
2014-04-28 9:25 ` Peter Zijlstra
2014-04-28 10:14 ` Peter Zijlstra
2014-04-27 16:21 ` Linus Torvalds
2014-04-27 23:13 ` Benjamin Herrenschmidt
2014-04-25 16:54 ` Dave Hansen
2014-04-25 18:41 ` Hugh Dickins
2014-04-25 22:00 ` Dave Hansen
2014-04-26 3:11 ` Hugh Dickins
2014-04-26 3:48 ` Linus Torvalds
2014-04-25 17:56 ` Linus Torvalds
2014-04-25 19:13 ` Hugh Dickins
2014-04-25 16:30 ` Dave Hansen
2014-04-23 20:11 ` Hugh Dickins
2014-04-24 8:49 ` Jan Kara
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