From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Ross Lagerwall <ross.lagerwall@citrix.com>,
xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] xen/grant-table: Use put_page instead of free_page
Date: Tue, 16 Jan 2018 13:47:01 -0500 [thread overview]
Message-ID: <6d3faf73-c8aa-db9a-1629-a9de85a1b377@oracle.com> (raw)
In-Reply-To: <20180111093638.28937-2-ross.lagerwall@citrix.com>
On 01/11/2018 04:36 AM, Ross Lagerwall wrote:
> The page given to gnttab_end_foreign_access() to free could be a
> compound page so use put_page() instead of free_page() since it can
> handle both compound and single pages correctly.
>
> This bug was discovered when migrating a Xen VM with several VIFs and
> CONFIG_DEBUG_VM enabled. It hits a BUG usually after fewer than 10
> iterations. All netfront devices disconnect from the backend during a
> suspend/resume and this will call gnttab_end_foreign_access() if a
> netfront queue has an outstanding skb. The mismatch between calling
> get_page() and free_page() on a compound page causes a reference
> counting error which is detected when DEBUG_VM is enabled.
>
> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
next prev parent reply other threads:[~2018-01-16 18:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-11 9:36 [PATCH 0/2] Fix a couple of crashes in netfront Ross Lagerwall
2018-01-11 9:36 ` [PATCH 1/2] xen/grant-table: Use put_page instead of free_page Ross Lagerwall
2018-01-11 15:48 ` Ross Lagerwall
2018-01-16 18:47 ` Boris Ostrovsky [this message]
2018-01-11 9:36 ` [PATCH 2/2] xen-netfront: Fix race between device setup and open Ross Lagerwall
2018-01-11 15:26 ` David Miller
2018-01-11 15:49 ` Ross Lagerwall
2018-01-11 16:08 ` David Miller
2018-01-11 16:27 ` Ross Lagerwall
2018-01-11 16:36 ` David Miller
2018-01-16 18:56 ` Boris Ostrovsky
2018-01-11 15:48 ` [PATCH 0/2] Fix a couple of crashes in netfront Ross Lagerwall
2018-02-06 14:52 ` Juergen Gross
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