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Message-ID: <20200724124241.48208-2-roger.pau@citrix.com>
Date: Fri, 24 Jul 2020 14:42:38 +0200
From: Roger Pau Monne <roger.pau@...rix.com>
To: <linux-kernel@...r.kernel.org>
CC: Roger Pau Monne <roger.pau@...rix.com>, <stable@...r.kernel.org>,
"Boris Ostrovsky" <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>,
Stefano Stabellini <sstabellini@...nel.org>,
<xen-devel@...ts.xenproject.org>
Subject: [PATCH v2 1/4] 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@...rix.com>
Cc: stable@...r.kernel.org
---
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Stefano Stabellini <sstabellini@...nel.org>
Cc: xen-devel@...ts.xenproject.org
---
drivers/xen/balloon.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 77c57568e5d7..3cb10ed32557 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -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);
--
2.27.0
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