From: Mel Gorman <mgorman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-mm@kvack.org, linux-s390@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com
Subject: Re: [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390
Date: Mon, 8 Oct 2012 15:28:23 +0100 [thread overview]
Message-ID: <20121008142823.GL29125@suse.de> (raw)
In-Reply-To: <1349108796-32161-1-git-send-email-jack@suse.cz>
On Mon, Oct 01, 2012 at 06:26:36PM +0200, Jan Kara wrote:
> On s390 any write to a page (even from kernel itself) sets architecture
> specific page dirty bit. Thus when a page is written to via standard write, HW
> dirty bit gets set and when we later map and unmap the page, page_remove_rmap()
> finds the dirty bit and calls set_page_dirty().
>
> Dirtying of a page which shouldn't be dirty can cause all sorts of problems to
> filesystems. The bug we observed in practice is that buffers from the page get
> freed, so when the page gets later marked as dirty and writeback writes it, XFS
> crashes due to an assertion BUG_ON(!PagePrivate(page)) in page_buffers() called
> from xfs_count_page_state().
>
> Similar problem can also happen when zero_user_segment() call from
> xfs_vm_writepage() (or block_write_full_page() for that matter) set the
> hardware dirty bit during writeback, later buffers get freed, and then page
> unmapped.
>
> Fix the issue by ignoring s390 HW dirty bit for page cache pages in
> page_mkclean() and page_remove_rmap(). This is safe because when a page gets
> marked as writeable in PTE it is also marked dirty in do_wp_page() or
> do_page_fault(). When the dirty bit is cleared by clear_page_dirty_for_io(),
> the page gets writeprotected in page_mkclean(). So pagecache page is writeable
> if and only if it is dirty.
>
> CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
> CC: Mel Gorman <mgorman@suse.de>
> CC: linux-s390@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com, Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-s390@vger.kernel.org
Subject: Re: [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390
Date: Mon, 8 Oct 2012 15:28:23 +0100 [thread overview]
Message-ID: <20121008142823.GL29125@suse.de> (raw)
In-Reply-To: <1349108796-32161-1-git-send-email-jack@suse.cz>
On Mon, Oct 01, 2012 at 06:26:36PM +0200, Jan Kara wrote:
> On s390 any write to a page (even from kernel itself) sets architecture
> specific page dirty bit. Thus when a page is written to via standard write, HW
> dirty bit gets set and when we later map and unmap the page, page_remove_rmap()
> finds the dirty bit and calls set_page_dirty().
>
> Dirtying of a page which shouldn't be dirty can cause all sorts of problems to
> filesystems. The bug we observed in practice is that buffers from the page get
> freed, so when the page gets later marked as dirty and writeback writes it, XFS
> crashes due to an assertion BUG_ON(!PagePrivate(page)) in page_buffers() called
> from xfs_count_page_state().
>
> Similar problem can also happen when zero_user_segment() call from
> xfs_vm_writepage() (or block_write_full_page() for that matter) set the
> hardware dirty bit during writeback, later buffers get freed, and then page
> unmapped.
>
> Fix the issue by ignoring s390 HW dirty bit for page cache pages in
> page_mkclean() and page_remove_rmap(). This is safe because when a page gets
> marked as writeable in PTE it is also marked dirty in do_wp_page() or
> do_page_fault(). When the dirty bit is cleared by clear_page_dirty_for_io(),
> the page gets writeprotected in page_mkclean(). So pagecache page is writeable
> if and only if it is dirty.
>
> CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
> CC: Mel Gorman <mgorman@suse.de>
> CC: linux-s390@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com, Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-s390@vger.kernel.org
Subject: Re: [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390
Date: Mon, 8 Oct 2012 15:28:23 +0100 [thread overview]
Message-ID: <20121008142823.GL29125@suse.de> (raw)
In-Reply-To: <1349108796-32161-1-git-send-email-jack@suse.cz>
On Mon, Oct 01, 2012 at 06:26:36PM +0200, Jan Kara wrote:
> On s390 any write to a page (even from kernel itself) sets architecture
> specific page dirty bit. Thus when a page is written to via standard write, HW
> dirty bit gets set and when we later map and unmap the page, page_remove_rmap()
> finds the dirty bit and calls set_page_dirty().
>
> Dirtying of a page which shouldn't be dirty can cause all sorts of problems to
> filesystems. The bug we observed in practice is that buffers from the page get
> freed, so when the page gets later marked as dirty and writeback writes it, XFS
> crashes due to an assertion BUG_ON(!PagePrivate(page)) in page_buffers() called
> from xfs_count_page_state().
>
> Similar problem can also happen when zero_user_segment() call from
> xfs_vm_writepage() (or block_write_full_page() for that matter) set the
> hardware dirty bit during writeback, later buffers get freed, and then page
> unmapped.
>
> Fix the issue by ignoring s390 HW dirty bit for page cache pages in
> page_mkclean() and page_remove_rmap(). This is safe because when a page gets
> marked as writeable in PTE it is also marked dirty in do_wp_page() or
> do_page_fault(). When the dirty bit is cleared by clear_page_dirty_for_io(),
> the page gets writeprotected in page_mkclean(). So pagecache page is writeable
> if and only if it is dirty.
>
> CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
> CC: Mel Gorman <mgorman@suse.de>
> CC: linux-s390@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-10-08 14:26 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-01 16:26 [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390 Jan Kara
2012-10-01 16:26 ` Jan Kara
2012-10-01 16:26 ` Jan Kara
2012-10-08 14:28 ` Mel Gorman [this message]
2012-10-08 14:28 ` Mel Gorman
2012-10-08 14:28 ` Mel Gorman
2012-10-09 4:24 ` Hugh Dickins
2012-10-09 4:24 ` Hugh Dickins
2012-10-09 4:24 ` Hugh Dickins
2012-10-09 8:18 ` Martin Schwidefsky
2012-10-09 8:18 ` Martin Schwidefsky
2012-10-09 8:18 ` Martin Schwidefsky
2012-10-09 23:21 ` Hugh Dickins
2012-10-09 23:21 ` Hugh Dickins
2012-10-09 23:21 ` Hugh Dickins
2012-10-10 21:57 ` Hugh Dickins
2012-10-10 21:57 ` Hugh Dickins
2012-10-10 21:57 ` Hugh Dickins
2012-10-19 14:38 ` Martin Schwidefsky
2012-10-19 14:38 ` Martin Schwidefsky
2012-10-19 14:38 ` Martin Schwidefsky
2012-10-09 9:32 ` Mel Gorman
2012-10-09 9:32 ` Mel Gorman
2012-10-09 9:32 ` Mel Gorman
2012-10-09 23:00 ` Hugh Dickins
2012-10-09 23:00 ` Hugh Dickins
2012-10-09 23:00 ` Hugh Dickins
2012-10-09 16:21 ` Jan Kara
2012-10-09 16:21 ` Jan Kara
2012-10-09 16:21 ` Jan Kara
2012-10-10 2:19 ` Hugh Dickins
2012-10-10 2:19 ` Hugh Dickins
2012-10-10 2:19 ` Hugh Dickins
2012-10-10 8:55 ` Jan Kara
2012-10-10 8:55 ` Jan Kara
2012-10-10 8:55 ` Jan Kara
2012-10-10 21:28 ` Hugh Dickins
2012-10-10 21:28 ` Hugh Dickins
2012-10-10 21:28 ` Hugh Dickins
2012-10-11 7:42 ` Martin Schwidefsky
2012-10-11 7:42 ` Martin Schwidefsky
2012-10-11 7:42 ` Martin Schwidefsky
2012-10-10 21:56 ` Dave Chinner
2012-10-10 21:56 ` Dave Chinner
2012-10-10 21:56 ` Dave Chinner
2012-10-11 7:44 ` Martin Schwidefsky
2012-10-11 7:44 ` Martin Schwidefsky
2012-10-11 7:44 ` Martin Schwidefsky
2012-10-17 0:43 ` Jan Kara
2012-10-17 0:43 ` Jan Kara
2012-10-17 0:43 ` Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2012-10-22 15:06 Jan Kara
2012-10-22 19:38 ` Andrew Morton
2012-10-23 4:40 ` Hugh Dickins
2012-10-23 10:21 ` Jan Kara
2012-10-23 21:56 ` Andrew Morton
2012-10-24 8:30 ` Martin Schwidefsky
2012-10-25 20:01 ` Jan Kara
2012-12-14 8:45 ` Martin Schwidefsky
2012-12-17 23:31 ` Hugh Dickins
2012-12-18 7:30 ` Martin Schwidefsky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121008142823.GL29125@suse.de \
--to=mgorman@suse.de \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=schwidefsky@de.ibm.com \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.