| From 1951fa33ec259abdf3497bfee7b63e7ddbb1a394 Mon Sep 17 00:00:00 2001 |
| From: Roger Pau Monne <roger.pau@citrix.com> |
| Date: Mon, 27 Jul 2020 11:13:39 +0200 |
| Subject: xen/balloon: fix accounting in alloc_xenballooned_pages error path |
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| |
| From: Roger Pau Monne <roger.pau@citrix.com> |
| |
| 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: 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/xen/balloon.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/drivers/xen/balloon.c |
| +++ b/drivers/xen/balloon.c |
| @@ -631,6 +631,12 @@ int alloc_xenballooned_pages(int nr_page |
| 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); |
