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Commit 3ac7292a authored by Ross Lagerwall's avatar Ross Lagerwall Committed by Juergen Gross
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xen/grant-table: Use put_page instead of free_page



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: default avatarRoss Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 4f277295
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