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 <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
