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Commit ee4c180d authored by Roger Pau Monne's avatar Roger Pau Monne Committed by Greg Kroah-Hartman
Browse files

xen/balloon: fix accounting in alloc_xenballooned_pages error path 



commit 1951fa33ec259abdf3497bfee7b63e7ddbb1a394 upstream.

target_unpopulated is incremented with nr_pages at the start of the
function, but the call to free_xenballooned_pages will only subtract
pgno number of pages, and thus the rest need to be subtracted before
returning or else accounting will be skewed.

Signed-off-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-2-roger.pau@citrix.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent db1f4c74

drivers/xen/balloon.c

+6 −0
Original line number Diff line number Diff line
@@ -632,6 +632,12 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages) 
 out_undo:

	mutex_unlock(&balloon_mutex);

	free_xenballooned_pages(pgno, pages);

	/*

	 * NB: free_xenballooned_pages will only subtract pgno pages, but since

	 * target_unpopulated is incremented with nr_pages at the start we need

	 * to remove the remaining ones also, or accounting will be screwed.

	 */

	balloon_stats.target_unpopulated -= nr_pages - pgno;

	return ret;

}

EXPORT_SYMBOL(alloc_xenballooned_pages);