Commit 1951fa33 authored Jul 27, 2020 by Roger Pau Monne Committed by Juergen Gross Aug 03, 2020

xen/balloon: fix accounting in alloc_xenballooned_pages error path



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: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen 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: Juergen Gross <jgross@suse.com>

parent 4e722d4f

drivers/xen/balloon.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -630,6 +630,12 @@ 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);

Admin message